At what temperature would a 1.50 m nacl solution freeze, given that the van't hoff factor for nacl is 1.9? kf for water is 1.86 ∘c/m .

Answers

Answer 1

Final answer:

To determine the freezing point of a 1.50 m NaCl solution, we need to calculate the freezing point depression using the formula: ΔT = Kf × m × i, where ΔT is the freezing point depression, Kf is the freezing point depression constant for water, m is the molality of the solution, and i is the van 't Hoff factor. In this case, the van 't Hoff factor for NaCl is given as 1.9. The freezing point of the solution can be found by subtracting the calculated freezing point depression from the freezing point of pure water.

Explanation:

To determine the freezing point of a 1.50 m NaCl solution, we need to calculate the freezing point depression using the formula:

ΔT = Kf × m × i,

where ΔT is the freezing point depression, Kf is the freezing point depression constant for water, m is the molality of the solution, and i is the van 't Hoff factor. In this case, the van 't Hoff factor for NaCl is given as 1.9.

Let's substitute the given values into the formula:

ΔT = 1.86 °C/m × 1.50 m × 1.9,

ΔT = 5.31 °C.

To find the freezing point of the solution, we subtract the calculated freezing point depression from the freezing point of pure water, which is 0 °C:

Freezing point = 0 °C - 5.31 °C = -5.31 °C.

Therefore, the 1.50 m NaCl solution would freeze at a temperature of -5.31 °C.


Related Questions

How many molecules of sulfur trioxide are present in 1.87 moles of this compound?

Answers

the  number  of  molecules  of  sulfur  trioxide  are  present   in  1.87  moles  of  this  compound    is  calculate  using  Avorgadro  law  constant  that  is

1  mole =  6.02  x10^23 moecules
what   about  1.87  moles
  1,87  x  6.02  x10^23 =  1.257  x10^24  molecules

Discuss how forests act as carbon sinks.

Answers

It absorbes more carbon from the atmosphere than it releases. It is then absorbed from the atmosphere through photosynthesis and then it becomes deposited in the forest biomass.

Answer:

They undergo photosynthesis which makes the carbon dioxide to be used rather than produced.

Explanation:

Hello,

Forests are widely known as the "Earth's lungs" due to the photosynthesis that vegetable life constantly perform as the carbon dioxide that is in the environment is used by them to produce energy, glucose and oxygen considering such metabolic pathway. Now, forest act as carbon sinks as the proportion between carbon dioxide consumers to producers is by far greater than 1 as long as there are more plants that use higher amounts of carbon dioxide than those that are released during the respiration of animals or any other natural process producing carbon dioxide.

Best regards.

When heat is removed from a substance, describe how the molecules are affected, what are causing these changes, describe what's happening in whole, and does the temp. increase or decrease?

Answers

Hello!

When heat is removed from a substance, the kinetic energy of the molecules decreases (the molecules start to move more slowly).

The changes are caused by the tendency of the system to reach equilibrium
and when the surroundings of the substance have lower kinetic energy, heat is transferred to reach thermodynamic equilibrium.

What's happening in whole is that there is a temperature gradient (difference) between the substance and its surroundings, and for eliminating this gradient, heat flows from the hotter substance to the colder surroundings, for them to have the same temperature.

The temperature of the substance decreases because its molecules have lower kinetic energy.

Have a nice day!
the molecules move slower and become compact 

Given the reaction: HSO4– + HPO42– ↔ SO42– + H2PO4-Which pair represents an acid and its conjugate base?

A) HSO4- and HPO42-
B) SO42- and H2PO4-
C) HSO4- and SO42-
D) SO42- and HPO42-

Answers

Hello!

The pair which represents an acid and its conjugate base is HSO₄⁻ and SO₄⁻².

To know if a pair of substances represents an acid and its conjugate base, one should look at the chemical structure of each substance. The conjugate base of an acid has usually the same chemical formula than the acid, but with one less proton (H⁺). Of the pairs of substances on the list, only HSO₄⁻ and SO₄⁻² have similar structures, with the only difference being the number of protons. The chemical reaction of dissociation of HSO₄⁻ is the following:

HSO₄⁻ + H₂O ⇄ SO₄⁻² + H₃O⁺

Have a nice day!



Money management becomes more important when you are responsible for paying all your own expenses.

Answers

Hi there!

You're answer is going to be -

True. Money management does become more important as you learn to pay you're own expenses.

Hope this helps! Have a great day!

~Alexa

Answer:

True

Explanation:

When you are responsible for paying your own expenses, you start to take more responsibility for how your money will be spent. At this point you begin to understand the importance and begin to value money management. Money management is the activity, where you decide how much of the money you have will be spent and what will be spent. When you pay your own expenses, you must manage your money well and ensure that all your needs, such as home, food, taxes, gasoline and other things are paid. If you do not manage your money you will end up spending on needless things and you may have some unpaid necessary expenses, which will cause problems for your life.

A solution of water (kf=1.86 ∘c/m) and glucose freezes at − 2.75 ∘c. what is the molal concentration of glucose in this solution? assume that the freezing point of pure water is 0.00 ∘c.

Answers

Answer is: the molal concentration of glucose in this solution is 1,478 m.
Tf(glucose) = -2,75°C.
Tf(water) = 0°C.
ΔT(solution) = 2,75°C.
Kf(water) = 1,86°C/m.
ΔT = Kf(water) · b(solution).
b(solution) = ΔT ÷ Kf(water).
b(solution) = 2,75°C ÷ 1,86°C/m.
b(solution) = 1,478 m = 1,478 mol/kg.

Explanation:

Relation between freezing temperature and molal concentration is as follows.

          [tex]\Delta T_{f} = k_{f} \times m[/tex]

The given data is as follows.

    [tex]\Delta T_{f}[/tex] = difference in temperature = [tex][0 - (-2.75)]^{o}C[/tex] = [tex]2.75^{o}C[/tex]

      [tex]k_{f} = 1.86^{o}C/mol[/tex]

            molality, (m) = ?  

Now, putting the given values into the above formula as follows.

                m = [tex]\frac{\Delta T_{f}}{k_{f}}[/tex]

                    = [tex]\frac{2.75^{o}C}{1.86^{o}C/mol}[/tex]

                    = 1.48 m

Therefore, we can conclude that molal concentration of glucose in the given solution is 1.48 m.

A detailed description of what Alexander Fleming was famous for?

Answers

Hello there!

Alexander Fleming was actually known for discoveries and of what he has invented. He made many things such as medicine, and also, certain substances such as enzyme lysozyme. He made many awards, noble prize, and other highly certificates that made him a very interesting person. This was the kind of person Alexander Fleming was.

I hope this helps you!

Complete and balance the molecular equation, including phases, for the reaction of aqueous copper(II) chloride, CuCl2, and aqueous potassium phosphate, K3PO4.

Answers

copper  (ii)  chloride  react  with  potassium  phosphate  to   form    copper (ii)  phosphate  and   potassium  chloride  according  to  the  following  equation

3CuCl2 (aq) +2 K3PO4 (aq) ----->  Cu(PO4)2 (aq)  +  6 Kcl (s)

Answer: The molecular equation is written below.

Explanation:

Every balanced chemical equation follows law of conservation of mass.

Law of conservation of mass states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form.

This also means that total mass on the reactant side must be equal to the total mass on the product side.

A molecular equation is the balanced chemical equation where the ionic compounds are expressed as molecules rather than constituent ions.

The chemical equation for the reaction of copper (II) chloride and potassium phosphate follows:

[tex]3CuCl_2(aq.)+2K_3PO_4(aq.)\rightarrow Cu_3(PO_4)_2(s)+6KCl[/tex]

By Stoichiometry of the reaction:

3 moles of copper (II) chloride reacts with 2 moles of potassium phosphate to produce 1 mole of copper (II) phosphate and 6 moles of potassium chloride.

Hence, the molecular equation is written above.

Which electron configuration represents the element carbon (atomic number 6)? A)1s2 2s2 2p6 B)1s2 2s2 2p4 C)1s2 2s2 2p2 D)1s2 2s2

Answers

Answer:
C) 1s2 2s2 2p2

Explanation:
We are given that carbon has atomic number 6. This means that carbon has 6 electrons.
1- The first level is composed of only one sublevel (s sublevel) and can hold only two electrons. Therefore, the first two carbon electrons will occupy 1s2
2- The second level is composed of two sublevels (s sublevel and p sublevel). The s sublevel can hold only two electrons while the p sublevel can hold up to six electrons. Since only four carbon electrons are to occupy the second level; two of them will be in the s sublevel (2s2) while the other two will occupy the p sublevel (2p2)

Combining the above, we will find that the configuration of carbon is:
1s2 2s2 2p2

Hope this helps :)

Final answer:

The electron configuration that represents carbon (atomic number 6) is 1s²2s²2p², reflecting two unpaired electrons in the 2p orbitals according to Hund's rule. So the correct option is C.

Explanation:

The correct electron configuration that represents the element carbon (atomic number 6) is C) 1s²2s²2p². Carbon has six electrons, and the way these electrons are distributed in the atom's orbitals determines the electron configuration. The first two electrons fill the 1s orbital, the next two fill the 2s orbital, and the remaining two occupy the 2p orbitals. According to Hund's rule, these two 2p electrons are unpaired in two different, but degenerate, p orbitals, maximizing the number of unpaired electrons and adhering to the Pauli exclusion principle. Thus, the electron configuration for carbon with its valence shell is represented as ns²np², where n represents the principal quantum number relevant to the orbital.

How many total atoms are in 0.330 g of P2O5?

Answers

A) covert 0.330g to moles by dividing by molar mass of P2O5 .. Let's call this Y moles
B) 1 mole of anything contains the Avogradro Number of molecules
So here it is 6.02 x 10^23 x Y molecules
C) work out how many atoms in each molecule 2P + 5O total 7
So multiply answer to B by 7 to get final answer

How many grams of AgNO3 are needed to prepare a 0.25 m solution in 500 grams of water?

Question options:

125 g


0.125g


21.25 g


170g

Answers

The answer would be 21.25g

What mass of natural gas (ch4) must you burn to emit 269 kj of heat? ch4(g)+2o2(g)âco2(g)+2h2o(g)δhârxn=â802.3kj express the mass in grams to three significant figures?

Answers

The mass of natural gas (CH₄) you need to burn to emit 269 kJ of heat is 5.38 g, expressed to three significant figures.

The combustion of methane is an exothermic reaction, meaning that it releases heat. The heat of combustion of methane is -802.3 kJ/mol, which means that 802.3 kJ of heat are released when 1 mole of methane is burned.

We can use this information to calculate the mass of methane needed to release 269 kJ of heat.

Mass of CH₄ = Heat / Heat of combustion

= 269 kJ / (-802.3 kJ/mol)

= 0.334 mol

= 5.38 g

Therefore, you need to burn 5.38 grams of methane to emit 269 kJ of heat.

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Final answer:

The mass of natural gas (CH4) that must be burned to emit 269 kJ of heat is 5.42 grams.

Explanation:

To calculate the mass of natural gas (CH4) that must be burned to emit 269 kJ of heat, we can use the enthalpy of combustion per mole of methane. According to the given balanced chemical equation, the enthalpy change of the combustion reaction is -802.3 kJ.

From a previous similar question, we know that when 2.50 g of methane burns, 125 kJ of heat is produced. So, we can set up a proportion to find the mass of CH4 that corresponds to 269 kJ of heat:

(2.50 g methane)/(125 kJ heat) = (x)/(269 kJ heat)

Solving for x, we find that x = 5.42 g. Therefore, the mass of natural gas that must be burned to emit 269 kJ of heat is 5.42 grams (to three significant figures).

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You carefully weigh out 10.00 g of caco3 powder and add it to 40.50 g of hcl solution. you notice bubbles as a reaction takes place. you then weigh the resulting solution and find that it has a mass of 46.40 g . the relevant equation is caco3(s)+2hcl(aq)→h2o(l)+co2(g)+cacl2(aq) assuming no other reactions take place, what mass of co2 was produced in this reaction?

Answers

Answer: 4.1g

The law of conservation of mass saying that the mass can't be created or destroyed. That means the total weight of reactant should be equal to the total weight of the product. But, if the reaction creates a gas product, the gas produced could fly away and makes the product lighter. The mass of the CO2 that goes away in this reaction would be:

reactant=product 
caco3 + HCL solution = CO2 + resulting solution
10g + 40.5g= CO2+ 46.4
CO2= 50.5g- 46.4g= 4.1g

The mass of CO₂ produced in the reaction is 4.10 grams.

To find the mass of CO₂ produced, we can use the law of conservation of mass, which states that mass is neither created nor destroyed in a chemical reaction.

The total mass of the reactants must equal the total mass of the products.

We start with the given masses of the reactants:

Mass of CaCO₃ = 10.00 g Mass of HCl solution = 40.50 g

The total mass of the reactants is the sum of the masses of CaCO₃ and the HCl solution:

Total mass of reactants = mass of CaCO₃ + mass of HCl solution Total mass of reactants = 10.00 g + 40.50 g Total mass of reactants = 50.50 g

After the reaction, we have the following:

Mass of the resulting solution = 46.40 g The mass of the products can be calculated by subtracting the mass of the reactants from the mass of the resulting solution: Mass of the products = Mass of the resulting solution - Mass of the reactants Mass of the products = 46.40 g - 50.50 g Mass of the products = -4.10 g

 The negative sign indicates that 4.10 grams of gas (CO₂) have been released from the solution, as the mass of the products is less than the mass of the reactants.

This is consistent with the observed bubbles, which are CO₂ gas being produced and escaping from the solution.

Therefore, the mass of CO₂ produced is 4.10 grams.

Neutralization is an important prart of digestion. Why?

Answers

it breaks away the proteins and nutrients you body uses 

breaks down proteins and nutrients

Write a balanced complete ionic equation for: hi(aq)+rboh(aq)→

Answers

The complete ionic equation for the reaction is as follows:

[tex]\boxed{{{\mathbf{H}}^ + }\left( q \right) + {{\mathbf{I}}^ - }\left( {aq} \right) + {\mathbf{R}}{{\mathbf{b}}^ + }\left( {aq} \right) + {\mathbf{O}}{{\mathbf{H}}^ - }\left( {aq} \right) \to {{\mathbf{H}}_{\mathbf{2}}}{\mathbf{O}}\left( l \right) + {{\mathbf{I}}^ - }\left( {aq} \right) + {\mathbf{R}}{{\mathbf{b}}^ + }\left( {aq} \right)}[/tex]

Further Explanation:

Double displacement reaction is defined as the reaction in which ions of two compound interchange with each other to form the product. For example, the general double displacement reaction between two compounds AX and BY  is as follows:

[tex]{\text{AX}} + {\text{BY}} \to {\text{AY}} + {\text{BX}}[/tex]

The three types of equations that are used to represent the chemical reaction are as follows:

1. Molecular equation

2. Complete ionic equation

3. Net ionic equation

The reactants and products remain in undissociated form in molecular equation. In the case of complete ionic equation, all the ions that are dissociated and present in the reaction mixture are represented while in the case of net ionic equation only the useful ions that participate in the reaction are represented.

The steps to write the complete ionic reaction are as follows:

Step 1: Write the molecular equation for the reaction with the phases in the bracket.

In the reaction, HI reacts with RbOH to form RbI and [tex]{{\text{H}}_{\text{2}}}{\text{O}}[/tex]. The balanced molecular equation of the reaction is as follows:

 [tex]{\text{HI}}\left( {aq} \right) + {\text{RbOH}}\left( {aq} \right) \to {\text{RbI}}\left( {aq} \right){\text{ + }}{{\text{H}}_{\text{2}}}{\text{O}}\left( l \right)[/tex]

Step 2: Dissociate all the compounds with the aqueous phase to write the complete ionic equation. The compounds with solid and liquid phase remain same. The complete ionic equation is as follows:

[tex]{{\mathbf{H}}^ + }\left( q \right) + {{\mathbf{I}}^ - }\left( {aq} \right) + {\mathbf{R}}{{\mathbf{b}}^ + }\left( {aq} \right) + {\mathbf{O}}{{\mathbf{H}}^ - }\left( {aq} \right) \to {{\mathbf{H}}_{\mathbf{2}}}{\mathbf{O}}\left( l \right) + {{\mathbf{I}}^ - }\left( {aq} \right) + {\mathbf{R}}{{\mathbf{b}}^ + }\left( {aq} \right)[/tex]

Learn more:

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

2. Oxidation and reduction reaction https://brainly.com/question/2973661

Answer details:

Grade: High School

Subject: Chemistry

Chapter: Chemical reaction and equation

Keywords: Double displacement reaction, types of equation, molecular equation, complete ionic equation, net ionic equation, RbI, RbOH, H2O, HI, chemical reaction.

Final answer:

To write a balanced complete ionic equation, first write the balanced chemical equation and then break it down into its ionic components. Finally, combine the ions to form the complete ionic equation.

Explanation:

To write a balanced complete ionic equation for the reaction between HI(aq) and RBOH(aq), we need to first write the balanced chemical equation:

HI(aq) + RBOH(aq) -> HRB(aq) + H2O(l)

Now, we can break down the equation into its ionic components:

HI(aq) -> H+(aq) + I-(aq)

RBOH(aq) -> RB+(aq) + OH-(aq)

HRB(aq) -> H+(aq) + RB-(aq)

H2O(l)

Putting it all together, the balanced complete ionic equation is:

H+(aq) + I-(aq) + RB+(aq) + OH-(aq) -> H+(aq) + RB-(aq) + H2O(l)

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Why do you heat the empty crucible?

Answers

It is important to establish the true weight of the crucible because it is a necessary reference point. Later, you will be weighing the crucible to determine how much of the products are present, so it's necessary to have the true tare weight of the crucible. 

The crucible is heated to be sure it is free of any moisture or other volatiles that might otherwise give a misleading weight. If you start out with the crucible absolutely clean and dry, (after heating) then you know that any additional weight must have come from the sample.

How many molecules of o2 are contained in a gas tank that contains 650. g of oxygen?

Answers

Avagadros constant states that there are 6.022 x 10²³ units in 1 mol of substance.
These units could be atoms that make up an element, or molecules making up a compound or ions as well.
1 mol of O₂ contains - 6.022 x 10²³ molecules of O₂
molecular mass of O₂ is (16*2) = 32 g/mol
1 mol of O₂ weighs = 32 g
Therefore in 32 g of O₂ - 6.022 x 10²³ O₂ molecules 
gas tank contains O₂ weighing 650 g
in 1 g   - 6.022 x 10²³/32 molecules 
in 650 g  - 6.022 x 10²³/32 * 650 
               = 2.96 x 10²² molecules of O₂

Which situation would be considered pseudoscience?

Students gather to identify species of plants in their neighborhood.
A student’s lucky necklace helps her win another volleyball tournament.
Students are successful in petitioning for organic food in the cafeteria.
A student tries eating all natural foods for one month to see if she has more energy.

Answers

The lucky necklace as it can't be proven.
Its the lucky necklace brah just gOoGLe it

Hydroxylamine is a weak molecular base with kb = 6.6 x 10-9. what is the ph of a 0.0500 m solution of hydroxylamine?

Answers

Answer is: pH of hydroxylamine solution is 9,23.

Kb(NH₂OH) = 1,8·10⁻⁵.
c₀(NH₂OH) = 0,0500 M = 0,05 mol/L.
c(NH₂⁺) = c(OH⁻) = x.

c(NH₂OH) = 0,05 mol/L - x.
Kb = c(NH₂⁺) · c(OH⁻) / c(NH₂OH).

0,0000000066 = x² /  (0,05 mol/L - x). 

solve quadratic equation: x = c(OH⁻) = 0,000018 mol/L.
pOH = -log(0,000018 mol/L) = 4,74.
pH = 14 - 4,74 = 9,23.


The pH of a 0.0500 M solution of hydroxylamine is 9.26.

To find the pH of a 0.0500 M solution of hydroxylamine, we need to find the hydroxide ion concentration [OH⁻] and then use the pOH-pH relationship.

Since hydroxylamine is a weak base, we can use the following equilibrium equation:

NH₂OH + H₂O ⇌ NH₃OH ⁺+ OH⁻

The base dissociation constant (Kb) is given as 6.6 x 10⁻⁹.

Let x be the concentration of hydroxide ions [OH⁻] formed. Then, the concentration of NH₃OH⁺ will also be x.

The initial concentration of hydroxylamine is 0.0500 M, and since it's a weak base, the amount of hydroxylamine that dissociates is very small compared to the initial concentration. Therefore, we can assume that the concentration of hydroxylamine remains approximately constant at 0.0500 M.

The equilibrium expression for Kb is:

Kb = [NH₃OH⁺][OH⁻] / [NH₂OH] = x² / 0.0500

Rearranging the equation to solve for x:

x² = Kb × 0.0500 = 6.6 x 10⁻⁹ × 0.0500 = 3.3 x 10⁻¹⁰

x = √(3.3 x 10⁻¹⁰) = 1.81 x 10⁻⁵ M

This is the concentration of hydroxide ions [OH⁻].

Now, we can find the pOH using the following equation:

pOH = -log[OH⁻] = -log(1.81 x 10⁻⁵) = 4.74

Finally, we can find the pH using the pOH-pH relationship:

pH + pOH = 14 pH = 14 - pOH = 14 - 4.74 = 9.26

Therefore, the pH of a 0.0500 M solution of hydroxylamine is 9.26.

Consider an amphoteric hydroxide, m(oh)2(s), where m is a generic metal. estimate the solubility of m(oh)2 in a solution buffered at ph

Answers

missing data in your question: (please check the attached photo)
from this balanced equation:
M(OH)2(s) ↔ M2+(aq) + 2OH-(aq) and when we have Ksp = 2x10^-16
∴Ksp = [M2+][OH]^2
2x10^-16 = [M2+][OH]^2
a) SO at PH = 7 
∴POH = 14-PH = 14- 7 = 7
when POH = -㏒[OH]
7= -㏒[OH]
∴[OH] = 1x10^-7 m by substitution with this value in the Ksp formula,
∴[M2+] =Ksp /[OH]^2
            = (2x10^-16)/(1x10^-7)^2
             = 0.02 M
b) at PH =10
when POH = 14- PH = 14-10 = 4 
when POH = -㏒[OH-]
            4  = -㏒[OH-]
∴[OH] = 1x10^-4 ,by substitution with this value in the Ksp formula
[M2+] = Ksp/ [OH]^2
          = 2x10^-16 / (1x10^-4)^2
          = 2x10^-8 M
c) at PH= 14 
when POH = 14-PH
                   = 14 - 14 
                   = 0
when POH = -㏒[OH]
              0 = - ㏒[OH]
∴[OH] = 1 m 
by substitution with this value in Ksp formula :
[M2+] = Ksp / [OH]^2
          = (2x10^-16) / 1^2
          = 2x10^-16 M


Final answer:

The solubility of an amphoteric hydroxide in a buffered solution depends on the pH of the solution. It can act as both an acid and a base. The Henderson-Hasselbalch equation can be used to estimate the solubility in a buffered solution.

Explanation:

The solubility of an amphoteric hydroxide, M(OH)2, in a buffered solution depends on the pH of the solution. An amphoteric hydroxide can act as both an acid and a base. At low pH, the hydroxide ion concentration is low and the hydroxide ion reacts with the excess hydronium ions, reducing the solubility. At high pH, the hydronium ion concentration is low and the hydroxide ion concentration is high, increasing the solubility. In a buffered solution, the pH remains relatively constant due to the presence of a weak acid and its conjugate base. The solubility of the hydroxide in the buffered solution can be estimated using the Henderson-Hasselbalch equation.

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During the process of transpiration, water _______ a plant through the _______.
A. enters; stomata
B. exits; stomata
C. exits; chloroplasts
D. enters; chloroplasts

Answers

Right answer is B . Trust me .

An 18 liter container holds 16.00 grams of oxygen gas (o2 at 45 °c. what is the pressure in the container?

Answers

Hello!

The pressure of an 18 L container which holds 16,00 grams of oxygen gas (O₂) at 45 °C is 0,725 atm

To solve this problem we first need to set up the data in the appropriate units to input it in the Ideal Gas Law.

a) 16 g of Oxygen gas to moles of oxygen gas:

[tex]16gO_2* \frac{1 mol O_2}{32gO_2}=0,5 mol O_2[/tex]

b) 45 °C to K

[tex]K=$^{\circ}$C + 273,15 = 45 $^{\circ}$C + 273.15=318,15 K [/tex]

Now, we clear the Ideal Gas Equation for P, and solve it:

[tex]P*V=n*R*T \\ \\ P= \frac{n*R*T}{V}= \frac{(0,5mol)*(0,082 \frac{L*atm}{mol*K})* (318,15 K)}{18 L}= 0,725 atm [/tex]

Have a nice day!

K12 3.10 Unit Assessment: Solutions, Part 1 does anyone have the answers for this quiz

Answers

Final answer:

The student is not provided with the direct answers to their K12 3.10 Unit Assessment (Chemistry). Instead, they are advised to review key concepts and principles from the unit, apply them to different contexts during the assessment, and utilise computational and analytical skills.

Explanation:

While it's not appropriate to provide the direct answers to your K12 3.10 Unit Assessment: Solutions, Part 1, I can help you understand how to arrive at correct solutions. The assessment likely includes both multiple-choice and short-response questions from various topics you've studied during the unit.

Critical Thinking Questions usually require you to apply concepts and principles you've learned to different contexts or situations. You might have to use analytic and computational skills to solve some problems. For instance, an example of a chemistry AP question could be asking you to calculate molarity of a solution, given the mass of the solute and volume of the solution.

Finally, review the materials from your textbooks and lessons, particularly the areas you feel less confident about. Practice using the concept to solve problems and try to understand the underlying principles. Good luck with your assessment!

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The combustion of 987.0 g of methane in the presence of excess oxygen produces 1.543 kg of carbon dioxide. What is the percent yield

Answers

Answer is: the percent yield is 56.85%.
Chemical reaction: CH₄ + 2O₂ → CO₂ + 2H₂O.
m(CH₄) = 987 g.
n(CH₄) = m(CH₄) ÷ M(CH₄).
n(CH₄) = 987 g ÷ 16 g/mol.
n(CH₄) = 61,68 mol.
From reaction: n(CH₄) : n(CO₂) = 1 : 1.
n(CO₂) = 61,68 mol.
m(CO₂) = 61,68 mol · 44 g/mol.
m(CO₂) = 2714,25 g ÷ 1000 g/kg = 2,714 kg.
yield = 1,543 kg ÷ 2,714 kg · 100 % = 56,85%.

If a solution containing 18.0 g of a substance reacts by first-order kinetics, how many grams remain after three half-lives?

Answers

Answer: 2.25 g

Explanation:

1) The half-life is the fime for which the initial concentration is decreased by half of the original concentration.

2) So, after every period of one half-life the concentration of the reactant will decrease by half.


3) In this case after 3 half-lives, the concentration will decrease by half 3 times which is 2^3 = 8

So, the amount that will remain will be 18.0 g / 8 = 2.25 g.

4) You can do it in 3 stages in this way:

One half-life => 18.0g / 2 = 9.0 g

Two half-lives => 9.0g / 2 = 4.5 g

Three half-lives => 4.5 g / 2 = 2.25 g

Based on the number of half-lives undergone by the substance,  the mass of the substance remaining after three half-lives is 2.25 g.

What is half-life of a substance?

The half-life of a substance is the time it will take for half the amount of the substance to decay or decompose.

The initial mass of the substance is 18.0 g

The substance undergoes three half-lives.

After the first half-life, mass remaining = 18/2 = 9.0 g

After the first half-life, mass remaining = 18/2 = 9.0 g

After the third half-life, mass remaining = 4.5/2 = 2.25 g

Therefore, the mass of the substance remaining after three half-lives is 2.25 g.

Learn more about half-life at: https://brainly.com/question/2320811

why is mercury the only metal to have been used in thermometers

Answers

Most metals are good conductors of heat and they are solids at room temperature. 

Mercury is liquid at room temperature, expands consistently, and doesn't wet glass, making it ideal for accurate temperature measurements in thermometers despite its toxicity.

Mercury is the only metal to have been used extensively in thermometers for several reasons. Firstly, it is the only metal that is liquid at room temperature, allowing it to easily expand and contract with temperature changes, making it excellent for precise temperature measurements. Additionally, mercury has a high coefficient of expansion, meaning it expands and contracts uniformly, resulting in accurate and consistent readings.

Mercury also does not wet glass, maintaining a clear meniscus that makes it easy to read the temperature. Its high density compared to other liquids, such as water, allows for more compact and portable thermometers. Despite its hazardous nature, these unique physical properties have historically made mercury the preferred choice for use in thermometers until safety concerns led to the adoption of safer alternatives like alcohol-filled instruments.

Calculate the residence time of sodium. Fill in the blanks.

Use T= m/f

Mass (m) Flow rate (f)
ton ton/year

Sodium 2.8 X 10^13 3.5 X 10^5

Zach is investigating the residence time of sodium in sea water. According to Zach's data table, the residence time of sodium written in scientific notation is _____________ X 10 _________ years.

Answers

Answer: 8.0 * 10^ 7 years

Explanation:

You just need to use the given equation with the two data also given.

1) Data:

m = 2.8 * 10^ 13 ton
f = 3.5 * 10^5 ton / year

2) Formula:

T = m/f

3) Solution

Subititute the values for the variables:

T = [2.8 * 10^ 13 tons ] / [3.5 * 10^ 5 ton / year] = 0.8 * 10^ 8 = 8.0 * 10^ 7 years.

Answer: 8.0 * 10^7 years.

Answer: 8 x 10^7

Explanation:

Calculate the volume in ml of 0.20m naoh needed to react completely with 100.ml of 0.040m acetic acid.

Answers

Hello!

You'll need 20 mL of 0,20 M NaOH to react completely with 100 mL of 0,040 M Acetic Acid. 

The reaction between NaOH and Acetic Acid is the following:

NaOH + CH₃COOH → H₂O + CH₃COONa

To calculate the volume of 0,20 M NaOH needed to react completely with 100 mL of 0,040 M Acetic Acid, we'll need to use the following equation (Molar equivalence) and clear for Volume of NaOH:

[tex]M_{NaOH}*V_{NaOH}=M_{CH_3COOH}*V_{CH_3COOH} \\ \\ V_{NaOH}= \frac{M_{CH_3COOH}*V_{CH_3COOH} }{M_{NaOH}} \\ \\ V_{NaOH}= \frac{0,040M*100 mL }{0.20}}=20 mL[/tex]

Have a nice day!

which state removed a physician's license to practice medicine.

Answers

Most of our data are based on published information from the Association of American Medical Colleges, the Educational Council for Foreign Medical Graduates, the American Board of Medical Specialties, and the National Resident Matching Program. Data on board-certified physicians were obtained from the Division of Survey and Data Resources of the American Medical Association and are not published elsewhere
i think thats right

What is the expected oxidation state for the most common ion of element 2

Answers

Answer: 1+

Justification:

The ionization energies tell the amount of energy needed to release an electron and form a ion. The first ionization energy if to loose one electron and form the ion with oxidation state 1+, the second ionization energy is the energy to loose a second electron and form the ion with oxidation state 2+, the third ionization energy is the energy to loose a third electron and form the ion with oxidation state 3+.

The low first ionization energy of element 2 shows it will lose an electron relatively easily to form the ion with oxidations state 1+.

The relatively high second ionization energy (and third too) shows that it is very difficult for this atom to loose a second electron, so it will not form an ions with oxidation state 2+. Furthermore, given the relatively high second and third ionization energies, you should think that the oxidation states 2+ and 3+ for element 2 never occurs.

Therefore, the expected oxidation state for the most common ion of element 2 is 1+.

The most common ion of helium (element 2), which rarely forms, has an expected oxidation state of 0 due to helium's full valence electron shell and its nature as a noble gas.

The expected oxidation state for the most common ion of element 2, which is helium (He), is 0. Because helium is a noble gas, it rarely forms ions and typically remains unreactive due to its full valence electron shell. Therefore, the oxidation number of any noble gas in its elemental state, including helium, is 0.

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