One liter of a buffer composed of 1.2 m hno2 and 0.8 m nano2 is mixed with 400 ml of 0.5 m naoh. what is the new ph? assume the pka of hno2 is 3.4.

Answers

Answer 1
Answer is: 3,4
Chemical reaction: HNO₂ + NaOH → NaNO₂ + H₂O.
c₀(HNO₂) = 1,2 M = 1,2 mol/dm³.
c₀(NaNO₂) = 0,8 M = 0,8 mol/dm³.
V₀(HNO₂) = V₀(NaNO₂)  = 1 dm³ = 1 L.
c₀(NaOH) = 0,5 M = 0,5 mol/dm³.
n₀(HNO₂)= 1,2 mol/dm³ · 1 dm³ = 1,2 mol.
n₀(NaNO₂) = 0,8 mol/dm³ · 1 dm³ = 0,8 mol.
V(NaOH) = 400 mL · 0,001 dm³/mL = 0,4 dm³.
n₀(NaOH) = c₀(NaOH) · V₀(NaOH).
n₀(NaOH) = 0,5 mol/dm³ · 0,4 dm³ = 0,2 mol.
n(HNO₂) = 1,2 mol - 0,2 mol = 1 mol.
n(NaNO₂) = 0,8 mol + 0,2 mol = 1 mol.
c(HNO₂) = 1 mol ÷ 1,4 dm³ = 0,714 mol/dm³.
c(NaNO₂) = 1 mol ÷ 1,4 dm³ = 0,714 mol/dm³.
pH = pKa + log (c(HNO₂) / c(NaNO₂)).
pH = 3,4 + log (0,714 mol/dm³ / 0,714 mol/dm³) = 3,4.
Answer 2

The new pH of given solutionis [tex]\boxed{3.53}[/tex].

Further Explanation:

The aqueous solution of a weak acid and its conjugate base or a weak base and its conjugate acid is termed as buffer solution. These solutions offer strong resistance to any change in their pH on addition of small quantity of strong acid or base.

Henderson-Hasselbalch equation:

This equation helps in determining the pH of buffer solution. Its mathematical form is given as follows:

[tex]{\text{pH}} = {\text{p}}{K_{\text{a}}} + {\text{log}}\dfrac{{\left[ {{{\text{A}}^ - }} \right]}}{{\left[ {{\text{HA}}} \right]}}[/tex]                                            …… (1)

Here,

[tex]\left[ {{{\text{A}}^ - }} \right][/tex] is concentration of conjugate base.

[HA] is concentration of acid.

Given mixture is a buffer solution of [tex]{\text{HN}}{{\text{O}}_{\text{2}}}[/tex] and [tex]{\text{NaN}}{{\text{O}}_{\text{2}}}[/tex]. Therefore Henderson-Hasselbalch equation becomes as follows:

[tex]{\text{pH}} = {\text{p}}{K_{\text{a}}} + {\text{log}}\dfrac{{\left[ {{\text{NaN}}{{\text{O}}_{\text{2}}}} \right]}}{{\left[ {{\text{HN}}{{\text{O}}_{\text{2}}}} \right]}}[/tex]                                                  …… (2)

Initial moles of [tex]{\text{HN}}{{\text{O}}_{\text{2}}}[/tex] can be calculated as follows:

[tex]\begin{aligned}{\text{Moles of HN}}{{\text{O}}_2} &= \left( {1.2{\text{ M}}} \right)\left( {{\text{1 L}}} \right)\\&= 1.2{\text{ mol}} \\\end{aligned}[/tex]  

Initial moles of [tex]{\text{NaN}}{{\text{O}}_{\text{2}}}[/tex]  can be calculated as follows:

[tex]\begin{aligned}{\text{Moles of NaN}}{{\text{O}}_{\text{2}}} &= \left( {0.8{\text{ M}}} \right)\left( {{\text{1 L}}} \right)\\&= 0.8{\text{ mol}} \\\end{aligned}[/tex]  

Moles of NaOH can be calculated as follows:

[tex]\begin{aligned}{\text{Moles of NaOH}} &= \left( {0.5{\text{ M}}} \right)\left( {{\text{400 mL}}} \right)\left( {\frac{{{{10}^{ - 3}}{\text{ L}}}}{{1{\text{ mL}}}}} \right) \\&= 0.2{\text{ mol}} \\\end{aligned}[/tex]  

When addition of 0.2 moles of NaOH is done to the buffer solution, 0.2 moles of [tex]{\text{HN}}{{\text{O}}_{\text{2}}}[/tex] is neutralized while the same amount of [tex]{\text{NaN}}{{\text{O}}_{\text{2}}}[/tex] is formed. Since volumes are additive, total volume can be calculated as follows:

[tex]\begin{aligned}{\text{Total volume of solution}} &= \left( {1 + \left( {400{\text{ mL}}} \right)\left( {\frac{{{{10}^{ - 3}}{\text{ L}}}}{{1{\text{ mL}}}}} \right)} \right){\text{ L}} \\ &= {\text{1}}{\text{.4 L}} \\\end{aligned}[/tex]

Therefore concentration of [tex]{\text{HN}}{{\text{O}}_{\text{2}}}[/tex] can be calculated as follows:

 [tex]\begin{aligned}\left[ {{\text{HN}}{{\text{O}}_{\text{2}}}} \right] &= \frac{{\left( {1.2 - 0.2} \right){\text{ mol}}}}{{1.4{\text{ L}}}}\\&= 0.714{\text{ M}} \\\end{aligned}[/tex]

Therefore concentration of [tex]{\text{NaN}}{{\text{O}}_{\text{2}}}[/tex] can be calculated as follows:

[tex]\begin{aligned}\left[ {{\text{NaN}}{{\text{O}}_{\text{2}}}} \right] &= \frac{{\left( {1.2 + 0.2} \right){\text{ mol}}}}{{1.4{\text{ L}}}} \\ &= 1{\text{ M}} \\\end{aligned}[/tex]  

Substitute 0.714 M for [tex]\left[ {{\text{HN}}{{\text{O}}_{\text{2}}}} \right][/tex], 1 M for [tex]\left[ {{\text{NaN}}{{\text{O}}_{\text{2}}}} \right][/tex] and 3.4 for [tex]{\text{p}}{K_{\text{a}}}[/tex] in equation (2).

[tex]\begin{aligned} {\text{pH}} &= 3.4 + {\text{log}}\left( {\frac{{{\text{1 M}}}}{{0.714{\text{ M}}}}} \right) \\&= 3.54 \\\end{aligned}[/tex]  

Learn more:

The reason for the acidity of water https://brainly.com/question/1550328 Reason for the acidic and basic nature of amino acid. https://brainly.com/question/5050077

Answer details:

Grade: High School

Subject: Chemistry

Chapter: Acid, base and salts

Keywords: pH, buffer, pKa, NaNO2, HNO2, 3.4, 1 M, 0.714 M, concentration, total volume of solution, 1.2 mol, 0.8 mol, 0.2 mol, 3.54.


Related Questions

The wittig reaction involves coupling between a phosphonium ylide and a carbonyl-containing molecule. if a chemist wants to use the wittig reaction to synthesize 2-methyl-2-pentene, which reactants should be used?

Answers

Final answer:

In the Wittig reaction to synthesize 2-methyl-2-pentene, a phosphonium ylide and a carbonyl-containing molecule, such as an aldehyde or a ketone, are needed as reactants.

Explanation:

The reactants needed for the Wittig reaction to synthesize 2-methyl-2-pentene are a phosphonium ylide and a carbonyl-containing molecule. In this case, the carbonyl-containing molecule should be an aldehyde or a ketone. The phosphonium ylide is usually generated from a phosphine and an alkyl halide. For example, one possible combination of reactants could be triphenylphosphine and methyl iodide to form the phosphonium ylide, which can then react with an aldehyde or ketone to produce 2-methyl-2-pentene.

Which law states that at constant temperature the pressure of a given amount of gas is inversely proportional to the volume of the gas?

Answers

He observed that volume of a given mass of a gas is inversely proportional to itspressure provided the temperature remains constant. Boyle's law, published in 1662,states that, at constant temperature, the product of the pressure and volume of agiven mass of an ideal gas in a closed system is always constant.

If the ph of a 1.00-in. rainfall over 1600 miles2 is 3.60, how many kilograms of sulfuric acid, h2so4, are present, assuming that it is the only acid contributing to the ph? for sulfuric acid, ka1 is very large and ka2 is 0.012.

Answers

The solution for this problem would be:
H + ions from pH = 4.0 x 10^-4 moles.
But H2SO4 gives off 2 moles of H+ ions / mole.
Moles of H2SO4 = 2.0 x 10^-4
Mass = 2 x 10^-4 moles x 98 = 1.96 x 10^-3 grams
1.96 x 10^-3 grams / 10^3 = 1.96 x 10^-6 Kg.

Suppose your thermometer is off by 1.5 oc i.e. it reads values that are 1.5 oc higher. how would this affect the results in this experiment? (3 pts)

Answers

I assume that the experiment is about calculating the enthalpy of a reaction. 
If you consistently use the thermometer for all procedure in the experiment, the effect will be negligible because all temperature will be increased by 1.5 °C.

In enthalpy calculation, the energy is determined by the temperature differences. If the final and initial temperature increased by 1.5 °C, then the difference will not be changed.

\Final answer:

A thermometer reading off by 1.5 °C would significantly impact the accuracy of experimental results by overestimating temperature values, potentially leading to incorrect conclusions in experiments that require precise temperature measurements.

Explanation:

If your thermometer is off by 1.5 °C, meaning it reads values that are 1.5 °C higher, this discrepancy would significantly affect the accuracy of your experimental results. This error would lead to consistently overestimated temperature readings, causing potential misinterpretations of the outcomes. For example, in experiments where precise temperature control and measurement are crucial, such as in testing product formulations or determining chemical reaction rates, an inaccurate thermometer could lead to incorrect assessments of these processes.

In laboratory settings, accurate temperature measurement is pivotal for ensuring the validity of experimental results. An error of 1.5 °C could not only impact the interpretation of a single experiment but also compound in experiments relying on precise temperature measurements to gauge reactions or behaviors, thereby misleading conclusions and potentially invalidating the experiment's purpose. Moreover, in cases like accelerated shelf life testing, a small temperature discrepancy could result in significant errors in the estimated product shelf life, underscoring the importance of using accurately calibrated equipment. Examples include estimating expiry dates based on the stability of products at increased temperatures where a minor measurement error could drastically skew the results. Hence, ensuring that laboratory equipment, especially thermometers, are correctly calibrated is essential for experimental integrity and accuracy.

How many grams of CaCl2 must be used to provide 0.252 moles of chloride ions?

Answers

Calcium chloride dissociates as follows:

CaCl₂(s) ⇄ Ca²⁺(aq) + 2Cl⁻(aq)

According to the dissociation equation, it can be seen that CaCl₂ and Cl⁻ ions have stoichiometric ratio:

n(CaCl₂) : n(Cl⁻) = 1 : 2

n(CaCl₂) = n(Cl⁻)/2

So, it is necessary 2 times more moles of calcium chloride for producing 1 mole of Cl⁻.

n(CaCl₂) = 0.252/2 = 0.126 mole

Finally, we can calculate the necessary mass of calcium chloride:

m(CaCl₂)  = n x M = 0.126 x 110.98 = 13.98 g of CaCl₂





To provide 0.252 moles of chloride ions, one would need 13.98428 grams of [tex]CaCl_2[/tex], using its molar mass of 110.98 g/mol and factoring in that each mole of [tex]CaCl_2[/tex] contains two moles of chloride ions.

To find out how many grams of calcium chloride ([tex]CaCl_2[/tex]) must be used to provide 0.252 moles of chloride ions, consider that each mole of [tex]CaCl_2[/tex] contains two moles of chloride ions. The molar mass of [tex]CaCl_2[/tex] is 110.98 g/mol.

To get the total number of moles of [tex]CaCl_2[/tex] needed, halve the number of chloride ions, which is [tex]\frac{0.252 moles}{2} = 0.126 moles[/tex] [tex]CaCl_2[/tex]. Then, use the molar mass to convert moles to grams:

0.126 moles [tex]CaCl_2[/tex] x 110.98 g/mol = 13.98428 grams of [tex]CaCl_2[/tex]

Therefore, you would need 13.98428 grams of [tex]CaCl_2[/tex] to provide 0.252 moles of chloride ions.

Write a net ionic equation for the overall reaction that occurs when aqueous solutions of phosphoric acid (h3po4) and potassium hydroxide are combined.assume excess base. use the pull-down boxes to specify states such as (aq) or (s).

Answers

Firstly, we have to show molecular equation (all compounds are showed as neutral molecules) for the reaction:

H₃PO₄(aq) + 3KOH(aq)  ⇒ K₃PO₄(aq) + 3H₂O(l) 

Then, the reaction has to be written as an ionic equation:

3H⁺(aq) + PO₄³⁻(aq) + 3K⁺(aq)+ 3OH⁻(aq) +   ⇒  3K⁺(aq) + PO₄³⁻(aq)  + 3H₂O(l) 

The molecule of water does not dissociate and it is shown as a molecule. Soluble ionic compounds H₃PO₄ and KOH are shown as dissociated ions.
Since there are not spectator ions (ions that do not participate in the reaction) the equation is at the same time and net ionic equation (ions and molecules involved in the reaction).

What is the molar mass of a substance?

a. the mass in grams of one mole of a substance
b. the number of particles in one gram of a substance
c. the number of moles in one gram of a substance
d. the mass in grams of one particle of a substance

Answers

Molar mass also called Atomic mass is the atomic weight. You can find this on the periodic table.
-
-
-
The answer would be
A. the mass in grams of one mole of a substance

Answer: Option (a) is the correct answer.

Explanation:

Molar mass is defined as the mass in grams of one mole of a substance.

Mathematically,       Molar mass = [tex]\frac{mass in grams}{moles of substance}[/tex]

For example, molar mass of 1 mole of [tex]CH_{4}[/tex] molecule will be calculated as follows.

             Molar mass of [tex]CH_{4}[/tex] = [tex]mass of carbon atom + 4 \times mass of hydrogen atom[/tex]

                                 = [tex]12 + 4 \times 1[/tex]

                                 = 16 g

Therefore, 1 mole of [tex]CH_{4}[/tex] molecules has a molar mass of 16 g.


What is the mass of platinum that has 4.34x10^21 of atoms?

Answers

Answer is: the mass of platinum is 1.405 grams.
N(Pt) = 4,34·10²¹.
n(Pt) = N(Pt) ÷ Na.
n(Pt) = 4,34·10²¹ ÷ 6,022·10²³ 1/mol.
n(Pt) = 0,0072 mol.
m(Pt) = n(Pt) · M(Pt).
m(Pt) = 0,0072 mol · 195 g/mol.
m(Pt) = 1,405 g.
n - amount of substance.
Na - Avogadro number.

The concentrations of the products at equilibrium are [pcl3] = 0.180 m and [cl2] = 0.250 m. what is the concentration of the reactant, pcl5, at equilibrium?

Answers

we have Kc = 4.2 x 10^-2 (given but missing in the question)
and When the balanced equation for this reaction is:
PCl5(g) ↔ PCl3(g) + Cl2(g)
so, according to the Kc formula:
Kc = the concentration of products / the concentration of the reactants
so, to get the concentration of the reactants in equilibrium, the concentration of the products / the concentration of the reactants should equal the Kc value which is given in the question (missing in your question).
So by substitution in Kc formula: 
Kc   = [PCl3]*[Cl2] / [PCl5]
4.2 x 10^-2 =  0.18 * 0.25 /[PCl5]
∴[PCl5] = 0.18*0.25 / 4.2x10^-2 = 1.07
So the concentration of the reactants in equilibrim = 1.07

Final answer:

The concentration of the reactant PCl5 at equilibrium can be found using the given equilibrium concentrations of the products and the equilibrium constant by rearranging the equilibrium expression and substituting the known values.

Explanation:

To determine the concentration of the reactant PCl5 at equilibrium, we use the equilibrium constant Ke for the reaction, which is given as 0.0211. Let's set up the equilibrium expression for this decomposition reaction:

PCl5 → PCl3 + Cl2

The equilibrium constant expression is:

Ke = [PCl3][Cl2] / [PCl5]

We can rearrange this equation to solve for [PCl5]:

[PCl5] = [PCl3][Cl2] / Ke

We substitute the given concentrations [PCl3] = 0.180 M and [Cl2] = 0.250 M into the equation:

[PCl5] = (0.180 M)(0.250 M) / 0.0211

By calculating the above equation, we find the concentration of PCl5 at equilibrium.

Match the element or group to the rule assigning its oxidation state.
(1.5 points) A. Oxygen B. Hydrogen C. Lone elements and atoms in gases D. Elements with multiple oxidation states E. Elements in groups 1, 2, and 17 and polyatomic ions
_____ 0
_____ Ionic charge
_____ +1, – 1 if bonded to a diatomic metal
_____ Almost always –2
_____ Determined by other elements in the compound

Answers

C. Lone elements and atoms in gases : 0

Elements in the free elemental have an oxidation number of zero

E. Elements in groups 1, 2, and 17 and polyatomic ions : Ionic charge

Group 1, 2, and 17 ions are formed by the alkali metals, alkaline metals and halogens respectively. Alkali metals, alkaline metals and halogens form +1, +2 and -1  ions respectively. Polyatiomic ions have -1, -2, -3 charges such as OH-, CO32-, PO43- respectively.

B. Hydrogen : +1, – 1 if bonded to a diatomic metal

H has an oxidation number of +1. H in metal hydrides such as NaH (sodium hydride) has an oxidation number of -1

A. Oxygen : Almost always –2  

O has an oxidation number of -2.

D. Elements with multiple oxidation states : Determined by other elements in the compound

V (vanadium) has different oxidation which depends on the compound in which V is found.

look at the thing attached

why is the solubility of khp in water greater than many fatty acids with six or more carbons?

Answers

Final answer:

KHP has greater water solubility than fatty acids with long hydrocarbon chains due to its polar carboxylate anion that allows for strong hydrogen bonding with water, whereas fatty acids have a hydrophilic region that becomes less significant relative to the hydrophobic chain as the chain length increases, leading to decreased solubility.

Explanation:

The solubility of potassium hydrogen phthalate (KHP) in water is greater than that of fatty acids with six or more carbons mainly due to the difference in the chemical structure and polarity of the molecules. KHP possesses a highly polar functional group (carboxylate anion) that can form strong hydrogen bonds with water molecules, whereas fatty acids have long hydrocarbon chains that exhibit a hydrophobic character and tend to be less soluble in polar solvents like water. As fatty acids increase in chain length, their solubility in water decreases because the proportion of the nonpolar, hydrophobic hydrocarbon chain relative to the polar carboxyl group becomes larger, resulting in weaker interactions with water molecules.

Fatty acids with long chains, such as those with more than eight carbons, are termed amphiphilic or amphipathic. These substances have both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions, which makes them behave differently in water. For instance, fatty acids with ten or more carbon atoms are nearly insoluble in water but can form a monolayer on the water surface, displaying properties characteristic of surfactants.

The higher solubility of KHP in water compared to fatty acids with six or more carbons is due to its ionic nature and the larger proportion of hydrophobic regions in long-chain fatty acids which decrease their solubility.

The higher solubility of potassium hydrogen phthalate (KHP) in water compared to many fatty acids with six or more carbons is attributed to both its ionic nature and structural differences.

KHP is an ionic compound, meaning it dissociates into ions (potassium and hydrogen phthalate ions) in water.

These ions interact strongly with water molecules through ion-dipole interactions, facilitating its dissolution. In contrast, fatty acids remain as neutral molecules in water, lacking the strong electrostatic interactions that promote solubility.

Additionally, KHP contains hydrophilic groups like the carboxylate group, which further enhance its solubility by forming hydrogen bonds with water molecules.

In contrast, the hydrophobic nature of fatty acids increases with longer carbon chains, leading to decreased solubility in water. The predominance of non-polar hydrocarbon chains in fatty acids reduces their ability to interact favorably with the polar solvent, further lowering their solubility.

Therefore, the combination of KHP's ionic nature and its structural features that promote interactions with water molecules explains why it exhibits higher solubility in water compared to many fatty acids with longer carbon chains

After you preform your experiment, you determine that the kf value for naphthalene is 6.91 °c/m . you are using 10g of naphthalene and added 1.0 g of your unknown. the the freezing point of the solvent decreased by 4.47 °c when the unknown was added. knowing this information, determine the molar mass of the unknown. g/mol

Answers

Answer is: molar mass of compound is 154,58 g/mol.
m(naphthalene) = 10 g = 0,01 kg.
m(unknown compound) = 1,00 g.
ΔT (solution) = 4,47 °C.
Kf(naphthalene) = 6,91°C/m; cryoscopic constant.
M(unknown compound) = Kf(naphthalene)· m(unknown compound) ÷ m(naphthalene) · ΔT(solution).
M(xylene) = 6,91°C/m · 1 g ÷ 0,01 kg · 4,47°C.
M(xylene) = 154,58 g/mol.

Based on the Kf value and mass of the solvent naphthalene, the molar mass of the unknown compound is 154.58 g/mol.

What is the molar mass of a substance?

The molar mass of a substance is the mass of one mole of that substance.

The molar mass of a substance can be calculated from the Kf value and mass of the solvent naphthalene as follows:

mass of naphthalene = 10 g or 0.01 kg.

mass of unknown compound = 1.00 g

ΔT of the solution = 4,47 °C.

Kf value of naphthalene = 6.91°C/m;

Molar mass of unknown compound = Kf(naphthalene) × mass of unknown compound/ mass of naphthalene × ΔT

Molar mass of the unknown compound = 6.91°C/m · 1 g ÷ 0.01 kg × 4,47°C.

Molar mass of the unknown compound = 154.58 g/mol.

Therefore, the molar mass of the unknown compound is 154.58 g/mol.

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Write a chemical equation depicting what happens to the salt in water.

Answers

NaCl(s) + H2O(l) = Na+(aq) + Cl-(aq)
Answer:

[tex]NaCl(s) + H_2O-->Na^{+}(aq)+Cl^{-}(aq)+H_2O[/tex]

Explanation:

1) NaCl is a solid ionic compound.

2) The ions in a crystal of Na Cl are Na(+) and Cl(-).

3) One fundamental property of the ionic compounds is that they dissociate completely in water, which means that the ions separate and are surrounded by molecules of water.

4) That property is what make these compounds electrolytes which means that the solutions conduct electricity (the ions carry the charge and form the flow of current).


What is the empirical formula of a molecule containing 65.5% carbon 5.5% hydrogen and 29% oxygen?

Answers

I assume C₃H₃O.

Hope I helped! Tell me if I'm wrong!

Answer: The empirical formula is [tex]C_{3}H_{3}O_1[/tex]  

Explanation:

If percentage are given then we are taking total mass is 100 grams.

So, the mass of each element is equal to the percentage given.

Mass of C = 65.5 g

Mass of H = 5.5 g

Mass of O = 29.0 g

Step 1 : convert given masses into moles.

Moles of C =[tex]\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{65.5g}{12g/mole}=5.5moles[/tex]

Moles of H =[tex]\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{5.5g}{1g/mole}=5.5moles[/tex]

Moles of O =[tex]\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{29g}{16g/mole}=1.8moles\approx 1moles[/tex]

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C = [tex]\frac{5.5}{1.8}=3[/tex]

For H = [tex]\frac{5.5}{1.8}=3[/tex]

For O =[tex]\frac{1.8}{1.8}=1[/tex]

The ratio of C : H  : O= 3: 3: 1

Hence the empirical formula is [tex]C_{3}H_{3}O_1[/tex]  

What mass of salt (nacl) should you add to 1.48 l of water in an ice cream maker to make a solution that freezes at -13.4 ∘c ? assume complete dissociation of the nacl and density of 1.00 g/ml for water?

Answers

Answer is: mass of salt is 311,15 g.
V(H₂O) = 1,48 l · 1000 ml/l = 1480 ml.
m(H₂O) = 1480 g = 1,48 kg.
d(solution) = 1,00 g/ml.
ΔT(solution) = 13,4°C = 13,4 K.
Kf = 1,86 K·kg/mol; cryoscopic constant of water
i(NaCl) = 2; Van 't Hoff factor.
ΔT(solution) = Kf · b · i.
b(NaCl) = 13,4 K ÷ (1,86 K·kg/mol · 2).
b(NaCl) = 3,6 mol/kg.
n(NaCl) = 3,6 mol · 1,48 kg= 5,328 mol.
m(NaCl) = 5,328 mol · 58,4 g/mol = 311,15 g.

Answer:

311.6g NaCl you should add

Explanation:

When you add a solute (NaCl) to solvent (Water), the freezing point of the solution decreases with regard to pure solvent following the equation:

ΔT = Kf × m × i

Where ΔT is change in temperature(From 0°C to -13.4°C), Kf is freezing point depression constant (1.86°C/m for water), m is molality of solution (Moles solute / 1.48 kg solvent -Because 1.48L≡1.48kg; density 1.00g/mL-) and i is Van't Hoff factor (2 for NaCl because in water, NaCl dissociates as Na⁺ and Cl⁻ ions, 2 ions).

Replacing:

13.4°C = 1.86°C/m × moles NaCl / 1.48kg × 2

5.33 = moles NaCl

As molar mass of NaCl is 58.44g/mol, mass in 5.33moles are:

5.33mol NaCl × (58.44g /mol) = 311.6g NaCl you should add

The mole fraction of iodine, i2, dissolved in dichloromethane, ch2cl2, is 0.115. what is the molal concentration, m, of iodine in this solution?

Answers

The molality of a solute is equal to the moles of solute per kg of solvent. We are given the mole fraction of I₂ in CH₂Cl₂ is X = 0.115. If we can an arbitrary sample of 1 mole of solution, we will have:

0.115 mol I₂

1 - 0.115 = 0.885 mol CH₂Cl₂

We need moles of solute, which we have, and must convert our moles of solvent to kg:

0.885 mol x 84.93 g/mol = 75.2 g CH₂Cl₂ x 1 kg/1000g = 0.0752 kg CH₂Cl₂

We can now calculate the molality:

m = 0.115 mol I₂/0.0752 kg CH₂Cl₂
m = 1.53 mol I₂/kg CH₂Cl₂

The molality of the iodine solution is 1.53.

What is the total number of valence electrons in the lewis structure of sef2o?

Answers

Final answer:

The total number of valence electrons in the Lewis structure of SEF2O is calculated by adding the valence electrons of each atom, giving us a total of 26 electrons.

Explanation:

The total number of valence electrons in the lewis structure of SEF2O can be calculated by adding up the valence electrons in each atom. Selenium (Se) has 6 valence electrons, each Fluorine (F) has 7 (so that's 14 for 2 Fluorines), and Oxygen (O) also has 6. So, the total number of valence electrons in SEF2O is 24+2 = 26.

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Final answer:

The total number of valence electrons in the Lewis structure of SeF2O is 26.

Explanation:

The Lewis structure of SeF2O consists of a central Se atom bonded to two F atoms and one O atom. To determine the total number of valence electrons, we need to add up the valence electrons of each particle. She has six valence electrons, each F atom has seven valence electrons, and O has six valence electrons. Therefore, the total number of valence electrons in the Lewis structure of SeF2O is 6 (Se) + 2(7) (F) + 6 (O) = 26.

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write complete ionic and net ionic equations for, SrCO3(s)+H2SO4(aq) -> SrSO4(s) +CO2(g)+H2O(l)

Answers

Chemical reaction: SrCO₃(s)+H₂SO₄(aq) → SrSO₄(s) +CO₂(g)+H₂O(l).
Ionic reaction: SrCO₃ + 2H⁺ + SO₄²⁻ → SrSO₄ + CO₂ + H₂O.
Strontium carbonate and strontium sulfate are salts insoluble in water. Sulfuric acid is strong acid. Carbone dioxide is gas, not dissolve in water. Water is a molecular liquid.

Which of the following would likely be part of an ionic bond? Choose all that apply.

A. K+1

B. Cl2

C. F–1

D. Ne

Answers

Hello!

K⁺ and F⁻ are the more likely to form an ionic bond.

Ionic bonds are the result of the electrostatic attraction between positive and negative ions (charged atoms). Of the listed substances, the ones that are charged are K⁺ and F⁻, so they are the ones that will form ionic bonds. Some ionic substances made from K⁺ include KCl (used in fertilizers) and some ionic substances made from F⁻ include NaF (used in dental therapy). 

Have a nice day!

the answer is A and C

Convert the pressure 0.840 atm to mm Hg

Answers

The pressure unit is Pascal (sign Pa) or Newton per square meter (N / m2). In addition to Pascal, a pressure measurement unit can be used bar (1 bar = 105 Pa). The old pressure units are: technical atmosphere, the symbol at (1 at = 98 066.5 Pa); standard, normal or physical atmosphere, atm (1 atm = 101 325 Pa); millimetres of mercury, the symbol mmHg, or torr (1 mmHg = 1 torr = 133,322 Pa); millimeter of water, symbol mmH2O (1 mmH2O = 9.806 65 Pa).

1 atm = 101 325 Pa
1 mmHg = 133,322 Pa

1 atm = 101 325/133.322 = 760 mmHg

0.84 atm = 760 x 0.84 = 638.4 mmHg
Final answer:

The pressure of 0.840 atmospheres (atm) can be converted to millimeters of mercury (mm Hg) by using the conversion factor, 1 atm = 760 mm Hg. The result of this conversion is 638.4 mm Hg.

Explanation:

To convert the pressure from atmospheres (atm) to millimeters of mercury (mm Hg), we use the conversion factor of 1 atm = 760 mm Hg. This is a known standard in chemistry and physics. In this case, the conversion will be as follows:

0.840 atm x 760 mm Hg/1 atm = 638.4 mm Hg

Therefore, 0.840 atm is equivalent to 638.4 mm Hg.

Learn more about Pressure Conversion here:

https://brainly.com/question/36152804

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Which of these is not a precaution taken at nuclear power plants to ensure safety? Safety systems are built into them. All parts are kept in good repair. Enriched uranium is the fuel source. Processes are carefully monitored.

Answers

Answer: Enriched uranium is the fuel source.

The nuclear power plants utilizes the radiation energy from the fission of the heavy molecular weight atomic particles. These radiations can cause damage when exposed to the external air, they are capable of causing explosion, mutation in the living beings. Therefore, safety measures should be taken to prevent the damages.

Enriched uranium is the fuel source is not the precaution taken at the nuclear power plant to ensure safety because it is just explaining the fact that the uranium is the source of radiation. All other factors such as safety systems are built into them, all parts are kept in good repair and processes are carefully monitored are relevant precautions.

Use the equation. How much SiCl4 is needed to produce 2.7 moles HCl?
SiCl4 + 4 H2O --> H4SiO4 + 4 HCl

Answers

4 moles of HCl are produced by 1 mole of SiCl4

2.7 moles of HCl will be produced if we have

2.7/4=0.675moles of SiCl4

molecular weight of SiCl4 =169.9g

amount of SiCl4 needed = 169.9 X 0.675=114.682g

114.682 g is the answer

Scientists found a fern fossil in some rock layers of the Grand Canyon. They estimated that a sample of one of the fossils originally contained 1000 carbon-14 atoms when it became 'fossilized', and at the time it was tested, it only contained 250 carbon-14 atoms. Look at the chart below. How old is the fossil?

Answers

This question is dealing with the half-life of carbon-14 which can be used to determine the age of a substance according to the following equation:

t = [ln(N/No)/(-ln2)] · t1/2

N = # of carbon-14 atoms presently = 250 atoms
No = # of carbon-14 atoms initially = 1000 atoms
t1/2 = half-life = 5730 years for carbon-14

We can now input all of the information into the formula to find the age of the fossil:

t = [ln (250/1000)/-ln2] x 5730 years

t = 11460 years

The fossil should be found to be roughly 11,460 years old.

The ka of benzoic acid is 6.4 x 10–5. what is the approximate ph of a 1.5 m solution of benzoic acid?

Answers

I don't know if you need the answer explain to you but here's the answer 2.00

Answer: 2.01

Explanation:

[tex]C_6H_5COOH\rightleftharpoons C_6H_5COO^-+H^+[/tex]

initial : c         0             0

eqm: [tex]c(1-\alpha)[/tex]     [tex]c\alpha[/tex]      [tex]c\alpha[/tex]  

[tex]K_a=\frac{c\alpha\times c\alpha}{c(1-\alpha)}[/tex]

when [tex]\alpha[/tex] is very very small the, the expression will be,

[tex]k_a=\frac{c^2\alpha^2}{c}=c\alpha^2\\\\\alpha=\sqrt{\frac{k_a}{c}}[/tex]

And,

[tex][H^+]=c\alpha[/tex]

Thus the expression will be,

[tex][H^+]=\sqrt{k_a\times c}[/tex]

Now put all the given values in this expression, we get

[tex][H^+]=\sqrt{(6.4\times 10^{-5})\times 1.5}[/tex]

[tex][H^+]=9.7\times 10^{-3}M[/tex]

[tex]pH=-log[H^+][/tex]

[tex]pH=-log[9.7\times 10^{-3}]=2.01[/tex]

What mass of phosphoric acid (h3po4, 98.0 g/mol) is produced from the reaction of 10.0 g of p4o10 (284 g/mol) with excess water?

Answers

when the balanced reaction equation is:
P4O10 + 6H2O→ 4 H3PO4
when we have the mass of P4O10 = 10 g  and the molar mass of P4O10=284 g/mol & we have the molar mass of H3PO4 =98 g/mol so we can get the mass of H3PO4 by substitution by:
mass of H3PO4 = (mass of P4O10)/(molar mass of P4O10) * 4(mol of H3PO4)*molar mass of H3PO4
∴mass of H3PO4 = (10 / 284) * 4 * 98 = 13.8 g

Answer : The mass of phosphoric acid produced is 6.89 grams.

Solution : Given,

Mass of [tex]P_4O_{10}[/tex] = 10.0 g

Molar mass of [tex]P_4O_{10}[/tex] = 284 g/mole

Molar mass of [tex]H_3PO_4[/tex] = 98.0 g/mole

First we have to calculate the moles of [tex]P_4O_{10}[/tex].

[tex]\text{ Moles of }P_4O_{10}=\frac{\text{ Mass of }P_4O_{10}}{\text{ Molar mass of }P_4O_{10}}=\frac{10.0g}{284g/mole}=0.0352moles[/tex]

Now we have to calculate the moles of [tex]MgO[/tex]

The balanced chemical reaction is,

[tex]P_4O_{10}+6H_2O\rightarrow 4H_3PO_4[/tex]

From the reaction, we conclude that

As, 1 mole of [tex]P_4O_{10}[/tex] react to give 2 mole of [tex]H_3PO_4[/tex]

So, 0.0352 moles of [tex]P_4O_{10}[/tex] react to give [tex]0.0352\times 2=0.0704[/tex] moles of [tex]H_3PO_4[/tex]

Now we have to calculate the mass of [tex]H_3PO_4[/tex]

[tex]\text{ Mass of }H_3PO_4=\text{ Moles of }H_3PO_4\times \text{ Molar mass of }H_3PO_4[/tex]

[tex]\text{ Mass of }H_3PO_4=(0.0704moles)\times (98.0g/mole)=6.89g[/tex]

Therefore, the mass of phosphoric acid produced is 6.89 grams.

Write the balanced chemical equation for the reverse reaction. include physical states for all species.

Answers

This is a missing part of your question:
The equilibrium system between sulfur dioxide gas, oxygen gas, and sulfur trioxide gas is given.
So you need the equilibrium balanced equation of SO2, O2, SO3 reaction:
First, we will start with the original equation which is not balanced yet (to understand how we get it):
SO2 + O2 ↔ SO3 
Here the number of O atom is not equal at the to sides
So we will start to balance our equation by make the number of O atom equal each other on both sides:
So we will start to put 2SO3 instead of SO3 
and put 2SO2 instead of SO2 to balance also the S atom on both sides
So we will get this:
2SO2(g) + O2(g)  2SO3(g) (This is our equilibrium balanced equation)
know we have a number of O atom equals on each side = 6
and the sulfur equals on each side = 2

The balanced equation for the reverse reaction would be

[tex]2SO_3 (g) < ----- > 2SO_2 (g) + O_2 (g)[/tex]

Reversible reactions

They are reactions that proceed in opposing directions - that is, reactants to products and vice versa.

The equilibrium system between sulfur dioxide gas, oxygen gas, and sulfur trioxide gas can be represented as:

[tex]2SO_2 (g) + O_2 (g) < --- > 2SO_3 (g)[/tex]

Thus, the reverse reaction would be:

[tex]2SO_3 (g) < ----- > 2SO_2 (g) + O_2 (g)[/tex]

More on equilibrium reactions can be found here: https://brainly.com/question/11114490

The equilibrium system between sulfur dioxide gas, oxygen gas, and sulfur trioxide gas is given. Write the balanced chemical equation for the reverse reaction. Include physical states for all species.

Which statement is correct regarding the rate of the reaction below? 3A + B yields 4X + 2Y

Answers

I added a image with the complete question as well as its choices.

Answer:
The rate of formation of X is 4 times the rate of disappearance of B

Explanation:
The given is:
3A + B .............> 4X + 2Y
From this, we can see that the ratio between the reactant B and the product X is 1 :4.
This means that for every reacting mole B, 4 moles of product X are formed, which means that the ratio between the disappearance of B and the formation of X is 1:4

Hope this helps :)

A tank of water contains many billions of water molecules. These molecules move at random speeds and in random directions, often colliding with each other. What form of energy does the water have due to the random motion of its particles?


thermal


radiant


chemical


potential

Answers

I think the answer is A. thermal.Hope this helps!:)

The energy due to the random motion of water molecules in a tank is thermal energy, which is related to the temperature of the water and can be transferred as heat.

The form of energy that water has due to the random motion of its molecules is called thermal energy. This energy arises from the kinetic energy that is present in the random microscopic motions of the water molecules. When these molecules move, collide, and bounce off each other, the average kinetic energy of these motions correlates with the temperature of the water. Furthermore, thermal energy can be transferred between objects or systems through processes like conduction, convection, and radiation, at which point it is commonly referred to as heat energy.

Hno3(aq)+k2so3(aq)→ express your answer as a chemical equation. identify all of the phases in your answer.

Answers

Answer : The balanced chemical reaction will be,

[tex]2HNO_3(aq)+K_2SO_3(aq)\rightarrow K_2SO_4(aq)+H_2O(l)+2NO_2(g)[/tex]

Explanation :

Balanced chemical equation : It is defined as the number of atoms of individual elements present on reactant side must be equal to the product side.

When the nitric acid react with potassium sulfite to give potassium sulfate, water and nitrogen dioxide.

Thus, the balanced chemical reaction will be,

[tex]2HNO_3(aq)+K_2SO_3(aq)\rightarrow K_2SO_4(aq)+H_2O(l)+2NO_2(g)[/tex]

The balanced chemical equation is as follows:

[tex]\boxed{{\text{2HN}}{{\text{O}}_{\text{3}}}\left( {aq} \right) + {{\text{K}}_2}{\text{S}}{{\text{O}}_3}\left( {aq} \right) \to {{\text{K}}_2}{\text{S}}{{\text{O}}_4}\left( {aq} \right) + 2{\text{N}}{{\text{O}}_{\text{2}}}\left( g \right) + {{\text{H}}_{\text{2}}}{\text{O}}\left( l \right)}[/tex]

The phase of [tex]{{\mathbf{K}}_{\mathbf{2}}}{\mathbf{S}}{{\mathbf{O}}_{\mathbf{4}}}[/tex] is [tex]\boxed{{\mathbf{aqueous}}}[/tex], [tex]{\mathbf{N}}{{\mathbf{O}}_{\mathbf{2}}}[/tex] is [tex]\boxed{{\mathbf{gas}}}[/tex] and [tex]{{\mathbf{H}}_{\mathbf{2}}}{\mathbf{O}}[/tex] is [tex]\boxed{{\mathbf{liquid}}}[/tex].

Further Explanation:

The chemical reaction that contains equal number of atoms of the different elements in the reactant as well as in the product side is known as balanced chemical reaction. The chemical equation is required to be balanced to follow the Law of the conservation of mass.

The steps to balance a chemical reaction are as follows:  

Step 1: Complete the reaction and write the unbalanced symbol equation.

In the given reaction, [tex]{\text{HN}}{{\text{O}}_{\text{3}}}[/tex] reacts with [tex]{{\text{K}}_2}{\text{S}}{{\text{O}}_3}[/tex] to form [tex]{{\text{K}}_2}{\text{S}}{{\text{O}}_4}[/tex], [tex]{\text{N}}{{\text{O}}_{\text{2}}}[/tex] and [tex]{{\text{H}}_{\text{2}}}{\text{O}}[/tex]. The physical state of [tex]{{\text{K}}_2}{\text{S}}{{\text{O}}_4}[/tex] is aqueous, [tex]{\text{N}}{{\text{O}}_{\text{2}}}[/tex] is gas and [tex]{{\text{H}}_{\text{2}}}{\text{O}}[/tex] is liquid. The unbalanced chemical equation is as follows:

[tex]{\text{HN}}{{\text{O}}_{\text{3}}}\left( {aq} \right) + {{\text{K}}_2}{\text{S}}{{\text{O}}_3}\left( {aq} \right) \to {{\text{K}}_2}{\text{S}}{{\text{O}}_4}\left( {aq} \right) + {\text{N}}{{\text{O}}_{\text{2}}}\left( g \right) + {{\text{H}}_{\text{2}}}{\text{O}}\left( l \right)[/tex]

Step 2: Then we write the number of atoms of all the different elements that are present in a chemical reaction in the reactant side and product side separately.(Refer table in the attached image)

On the reactant side,  

Number of hydrogen atoms is 1.

Number of nitrogen atoms is 1.

Number of oxygen atoms is 6.

Number of potassium atoms is 2.

Number of sulfur atoms is 1.

On the product side,  

Number of hydrogen atoms is 1.

Number of nitrogen atoms is 1.

Number of oxygen atoms is 6.

Number of potassium atoms is 2.

Number of sulfur atoms is 1.

Step 3: Initially, we try to balance the number of other atoms of elements except for carbon, oxygen, and hydrogen by multiplying with some number on any side. The other elements except oxygen and hydrogen are balanced.

Step 4: After this we balance the number of atoms of oxygen followed by hydrogen atoms. To balance the number of atoms of oxygen and hydrogen, we have to multiply [tex]{\text{HN}}{{\text{O}}_{\text{3}}}[/tex] by 2, [tex]{\text{N}}{{\text{O}}_{\text{2}}}[/tex] by 2. The chemical equation is as follows:

[tex]{\text{2HN}}{{\text{O}}_{\text{3}}}\left( {aq} \right) + {{\text{K}}_2}{\text{S}}{{\text{O}}_3}\left( {aq} \right) \to {{\text{K}}_2}{\text{S}}{{\text{O}}_4}\left( {aq} \right) + 2{\text{N}}{{\text{O}}_{\text{2}}}\left( g \right) + {{\text{H}}_{\text{2}}}{\text{O}}\left( l \right)[/tex]

Step 5: Finally, we check the number of atoms of each element on both the sides. If the number is same then the chemical equation is balanced. The balanced chemical equation is as follows:

[tex]{\text{HN}}{{\text{O}}_{\text{3}}}\left( {aq} \right) + {{\text{K}}_2}{\text{S}}{{\text{O}}_3}\left( {aq} \right) \to {{\text{K}}_2}{\text{S}}{{\text{O}}_4}\left( {aq} \right) + {\text{N}}{{\text{O}}_{\text{2}}}\left( g \right) + {{\text{H}}_{\text{2}}}{\text{O}}\left( l \right)[/tex]

Learn more:

1.  Balanced chemical equation https://brainly.com/question/1405182

2. How to calculate moles of the base in given volume https://brainly.com/question/4283309

Answer details:

Grade: High School

Subject: Chemistry

Chapter: Chemical reaction and equation

Keywords: Balancing, HNO3, K2SO4, K2SO3, NO2, H2O, phases, physical state, solid, liquid, gas, aqueous, law of conservation of mass.

what is 30-9x2*2-21-4+4

Answers

Answer:
9 (1-2x²)

Explanation:
The given expression is:
30 - 9x²*2 - 21 - 4 + 4
The first step is to compute the multiplication. This will give:
30 - 18x² - 21 - 4 + 4
Then, we will add like terms as follows:
(30-21-4+4) - 18x²
= 9 - 18x²
Finally, we can take the 9 as a common factor from both terms, this will give:
9 (1-2x²)

Hope this helps :)

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