how can an atom that has seven valence electrons complete its outermost level

Answers

Answer 1
It can form a covalent bond with a hydrogen bond that has one valence electron to have eight valence electrons and become stable.
Answer 2

Answer: The element needs to react with other element by gaining an electron to complete its valence electron.

Explanation: The element which exhibit 7 valence electrons are halogens. They readily react with other element, for example: Hydrogen and Sodium, in order to gain an electron to complete their outermost shell.


Related Questions

Write the net ionic equation (including phases) that corresponds to fe(clo4)2

Answers

1) The question is incomplete. What is the compound which Fe(ClO4)2 reacts with?

It could be one of several salts.

2) Assuming it is Na2S the complete reaction is:

Fe(ClO4)2 (aq) + Na2S(aq) → FeS (s) + 2NaClO4 (aq)

So, the next steps how how to work this problem assuming that reaction.

3) Show the ionic compounds as separate ions.

Fe(2+) (aq) + 2 ClO4(-) (aq) + 2 Na(+) (aq) + S(2-) (aq) → FeS(s) + 2 Na(aq) + 2 ClO4(-) (aq)

That is the total ionic equation.

4) Cancel the ions that appear on both sides of the equation , Na(+) and ClO4(-).

Fe(2+) (aq) + S(2-) (aq) → FeS(s)  <-------- this is the net ionic equation

What happens to sodium and perchlorate is that they do not participate in the reaction but remain dissolved which is called "spectator ions".


Final answer:

The compound Fe(ClO4)2 in water would dissociate into its ions, which are Fe²+ and 2ClO4¯. A specific net ionic equation cannot be given without knowledge of the reactants.

Explanation:

The net ionic equation would be the result of considering all the ions in the reaction of Fe(ClO4)2, which is iron(II) perchlorate, with all possible reactants. However, without knowing these reactants, we can't provide a specific net ionic equation. Generally, important concepts here include understanding how to balance equations and predict solubility based on common rules. In the case of Fe(ClO4)2 in water, this compound is highly soluble and would dissociate into its ions in water. Generally, you would expect it to dissociate into Fe²+ and 2ClO4¯ ions in solution.

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How long will it take for 20% of the u−238 atoms in a sample of u−238 to decay?

Answers

Answer is: it takes 1,448 billion years.
The half-life for the radioactive decay of U-238 is 4.5 billion years and is independent of initial concentration.
c₀ - initial concentration of U-238.
c - concentration of U-238 remaining at time.
t = 4,5·10⁹ y.
First calculate the radioactive decay rate constant λ:
λ = 0,693 ÷ t = 0,693 ÷ 4,5·10⁹ y = 1,54·10⁻¹⁰ 1/y.
ln(c/c₀) = -λ·t₁.
ln(0,8/1) = -1,54·10⁻¹⁰ 1/y · t₁.
t₁ = 1,448·10⁹ y.

It will require  for 20 % of U-238 atoms in a sample of U-238 to decay.

Further Explanation:

Radioactive decay involves stabilization of unstable atomic nucleus and is accompanied by the release of energy. This emission of energy can be in form of different particles like alpha, beta and gamma particles.

Half-life is time period in which half of the radioactive species is consumed. It is denoted by .

The expression for half-life is given as follows:

[tex]\lambda = \dfrac{{0.693}}{{{t_{{\text{1/2}}}}}}[/tex]                    …… (1)

Where,

[tex]{t_{{\text{1/2}}}}[/tex] is half-life period

[tex]\lambda[/tex] is the decay constant.

The half-life period for decay of U-238 is [tex]4.5 \times {10^9}{\text{ yrs}}[/tex].

Substitute [tex]4.5 \times {10^9}{\text{ yrs}}[/tex] for [tex]{t_{{\text{1/2}}}}[/tex]  in equation (1).

[tex]\begin{aligned}\lambda&= \dfrac{{0.693}}{{4.5 \times {{10}^9}{\text{ yrs}}}} \\&= 1.54 \times {10^{ - 10}}{\text{ yr}}{{\text{s}}^{ - 1}} \\\end{galigned}[/tex]  

Since it is radioactive decay, it is first-order reaction. Therefore the expression for rate of decay of U-238is given as follows:

[tex]\lambda = \dfrac{{2.303}}{t}\log \left( {\dfrac{a}{{a - x}}} \right)[/tex]

                                                …… (2)

Where,

[tex]\lambda[/tex] is the decay or rate constant.

t is the time taken for decay process.

a is the initial amount of sample.

x is the amount of sample that has been decayed.

Rearrange equation (2) to calculate t.

[tex]t = \dfrac{{2.303}}{\lambda }\log \left( {\dfrac{a}{{a - x}}} \right)[/tex]                                                                                          …… (3)

Consider 100 g to be initial amount of U-238. Since 20 % of it is decayed in radioactive process, 20 g of U-238 is decayed and therefore 80 g of the sample is left behind.

Substitute 100 g for a, 80 g for (a–x) and [tex]1.54 \times {10^{ - 10}}{\text{ yr}}{{\text{s}}^{ - 1}}[/tex] for [tex]\lambda[/tex] in equation (3).

[tex]\begin{aligned}t &= \dfrac{{2.303}}{{1.54 \times {{10}^{ - 10}}{\text{ yr}}{{\text{s}}^{ - 1}}}}\log \left( {\dfrac{{100{\text{ g}}}}{{80{\text{ g}}}}} \right)\\&= 1.449 \times {10^9}{\text{ yrs}}\\\end{aligned}[/tex]  

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Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Radioactivity

Keywords: half-life, t, a, x, a – x, 1.449*10^9 yrs, U-238, decay constant, radioactivity, half-life period.

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 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.

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]  

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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.

In two or more complete sentences, explain the law of conservation of mass and how it relates to this experiment?

Answers

I don't know the experiment so I cannot write about that but this is when mass is neither created nor destroyed. The mass of reactants is equal to the mass of products. 

Answer:

The mass can not be neither created nor destroyed but transformed by chemical reactions or physical transformations in an isolated recipient.

Explanation:

Hello,

In case, no matter the carried out experiment, the law of conservation of mass always leads the same: the mass can not be neither created nor destroyed but transformed by chemical reactions or physical transformations in an isolated recipient.

In such a way, we must consider that any system closed to every form of transport of matter, will show a no change in its mass as time goes by, since the system's mass cannot change neither by additions nor withdrawals. Therefore, the quantity of mass is conserved over time.

Best regards.

Are there any other methods you could use to determine phosphate content in the colas

Answers

Concentration of phosphate (phosphoric acid mostly) in soft drinks can be measured with acid-base titration. For titration sodium hydroxide solution is used. Hydrogen ions (H⁺) from the first dissociation of phosphoric acid react with hydroxide ions from sodium hydroxide: 
H₃PO₄(aq) + OH⁻ (aq) → H₂O(l) + H₂PO₄⁻ (aq).
Use pH sensor to monitor pH of titration solution. Determine the equivalence point (the region of most rapid pH change), measure the volume of sodium hydroxide titrant used at the equivalence point and calculate concentration of phosphate with concentration of used titrant.

One of the most important industrial sources of ethanol is the reaction of steam with ethene derived from crude oil: c2h4(g) + h2o(g) â c2h5oh(g)δh o rxn = â47.8 kjkc = 9.00 à 103 at 600. k at equilibrium, the partial pressure of ethanol (c2h5oh) is 200. atm and the partial pressure of water is 400. atm. calculate the partial pressure of ethene (c2h4).

Answers

We are asked to find the partial pressure of ethene given the equilibrium constant and the partial pressures of the other species. The reaction and equilibrium constant are shown below:

C₂H₄ (g) + H₂O (g) → C₂H₅OH (g)          Kc = 9 x 10³

Since we are given the equilibrium constant, Kc, which is regarding the concentration of species. However, we want the value of Kp which is the equilibrium constant regarding partial pressures. To convert these values we use the following formula:

Kp = Kc · (RT)ⁿ

R = 0.08206 Latm/molK
T = 600 K
Kc = 9 x 10³
Δn = sum of stoichiometric coefficients of products - sum of stoichiometric coefficients of reactants = -1

Kp = Kc/RT = (9 x 10³)/(0.08206)(600)
Kp = 183

Kp = [Pethanol]/[Pwater][Pethene] = 183
183 = (200)/(400)(Pethene)

P
ethene = (200)/(400)(183)
Pethene = 0.00273 atm

The partial pressure of ethene was found to be 0.00273 atm. This appears to be a very small number, however, it agrees with the scenario as we were told that the equilibrium constant was a very large number which suggests that the equilibrium falls far to the right. Based on this partial pressure of ethene, it appears that the majority of the ethene has reacted to form ethanol.

Kemmi pipets 25.00 ml of pure 1-propanol (c3h7oh, a liquid organic alcohol) into a 100.0 ml volumetric flask. she dilutes it with di water. help her calculate the strength of her diluted solution. volumes: 25.00 ml volumetric pipet, 100.00 ml volumetric flask. molar mass of pure 1-propanol: 60.09 g/mol. density of pure 1-propanol: 0.803 g/ml calculate the number of moles in exactly 25.00 ml of 1-propanol. (3 significant digits; units of mol) [x] calculate the molarity of the diluted solution. (3 significant digits; units of m or mol/l) [y]

Answers

Q1)
As Kemmi pipettes a volume of 25.00 ml of the solution
density of pure propanol is 0.803 g/ml
This means that in 1000 ml of solution - 0.803 g of pure propanol
Therefore in 25.00 ml of solution - 0.803 g x 25.00 ml / 1000 ml
                                                     = 0.0201 g
Using molar mass, number of moles can be calculated= 0.0201 g / 60.09 g/mol
                                                                                       = 3.35 x 10⁻⁴ mol
therefore the number of pure propanol moles in exactly 25.00 ml is
3.35 x 10⁻⁴ mol

Q2)
molarity is the concentration of the solution. It can be defined as the number of moles of solute per liter of solution
we know the number of moles in 25.00 ml of solution. When its diluted in a 100.00 ml volumetric flask, number of moles remain constant but now the volume over which the moles of solute are dissolved is increased.
therefore number of moles = 3.35 x 10^(-4) mol
volume over which its dissolved - 100.00 / 10³ dm³
                                                    = 1.0000 x10⁻¹ dm³
the molarity = 3.35 x 10⁻⁴ mol / 1.0000 x10⁻¹ dm³
                    = 3.35 x 10⁻³ mol/dm³

The number of moles of 1-propanol in 25.00 mL is 0.334 (to three significant digits). The molarity of the diluted 1-propanol solution in a 100.0 mL flask is 3.34 M (to three significant digits).

To calculate the number of moles of 1-propanol in 25.00 mL, we use the density of 1-propanol (0.803 g/mL) to find the mass:

Mass = Volume × Density = 25.00 mL  0.803 g/mL = 20.075 g

Next, we convert this mass to moles using the molar mass of 1-propanol (60.09 g/mol):

Moles of 1-propanol = Mass / Molar Mass = 20.075 g / 60.09 g/mol

This calculation yields 0.334 moles of 1-propanol (to three significant digits).

For the molarity of the diluted solution, we take into account that the total volume is now 100.0 mL. Since molarity is moles per liter (mol/L), we must first convert the volume from mL to L:

Volume in L = 100.0 mL (1 L / 1000 mL) = 0.100 L

Molarity = Moles of 1-propanol / Volume in L = 0.334 mol / 0.100 L

The molarity of the solution is 3.34 M (to three significant digits).

A 6 l volume of ideal neon gas (monatomic) is at a pressure of 3.2 atmospheres and a temperature of 310 k. the atomic mass of neon is 20.2 g/mol. in this situation, the temperature of the gas is increased to 410 and the volume is increased to 8.0 l. the final pressure of the gas, in atmospheres, is closest to:

Answers

Answer is: the final pressure of the gas is closest to 3,17 atm.

p₁ = 3,2 atm.
T₁ = 310 K.
V₁ = 6 L.
p₂ = ?
T₂ = 410K.
V₂ = 8,0 L.
Use combined gas law - the volume of amount of gas is proportional to the ratio of its Kelvin temperature and its pressure. 
p₁V₁/T₁ = p₂V₂/T₂.
3,2 atm · 6,0 L ÷ 310 K  = p₂ · 8,0 L ÷ 410 K.
0,0619 = 0,0195p₂.
p₂ = 3,17 atm.

As you have seen in this lab, the density of water is near 1 g/cm3. Anything with a density lower than this will float in water, and anything with a higher density will sink. Imagine you are building a submarine. How could you be sure to have it sink and then rise?

Make sure its density is always above 1.0 g/cm3.

Make sure its density is always below 1.0 g/cm3.

Develop a way to adjust its density so that it can be above and below 1.0 g/cm3.

Answers

The third answer is the one you want. You have to have an adjustable density. All other things being equal, if the tanks you use for holding just water when filled with water will let the sub sink, because the sub is made of a dense metal like iron or steel.

If on the other hand you fill these tanks with air, the net density will be below one and the sub will rise.

Answer: C) develop a way to adjust its density so that it can be above and below 1.0 gram per cubic centimeter.

Explanation: Submarine is a kind of special ship that can float above and below water. We know that an object can only float over water when its density is less than the density of water and it would sink if its density is greater than the density of water.

A submarine has tanks in which water is filled if we want to sink it and the water from the tanks is taken out with the help of water pumps to rise the submarine. These water tanks in the submarine helps to adjust its density.

The over all density is increased by filling the water tanks to sink the submarine and the density is decreased by removing the water from the tanks to rise the submarine.

So, option third or C is correct.

A reaction in which a , b , and c react to form products is zero order in a , one-half order in b , and second order in
c. by what factor does the reaction rate change if [b] is doubled (and the other reactant concentrations are held constant)? -g

Answers

For the reaction: A + B + C = products
when the rate law is:
r = K [A]^0 [B]^0.5 [C]^2 
  = K [B]^0.5 [C]^2
so the overall order of the reaction is 0 + 0.5 + 2 = 2.5
when the concentration of B is doubled and the concentrations of A and C are held constant so,
r1= [B(1)]^0.5  and r2 = [B(2)]^0.5 
∴ r2/r1 = [B(2)]^0.5 / [B(1)]^0.5 = 2^0.5 / 1^0.5 = 1.414
∴ the reaction will speed up 1.414 times
                                                 

Final answer:

When the concentration of b is doubled in a chemical reaction that is zero order in a, one-half order in b, and second order in c, the reaction rate will increase by a factor of √2 (approximately 1.414), with other reactant concentrations held constant.

Explanation:

The question you're asking relates to the rate of a chemical reaction and how it changes with varying concentrations of reactants. Specifically, there is a reaction where the rate is zero order in a, one-half order in b, and second order in c. According to the given reaction orders, the rate expression would be:

Rate = k [a]0[b]1/2[c]2

Since the reaction is zero order in a, changing the concentration of a does not affect the rate. However, since it is one-half order in b, if the concentration of b is doubled, the rate will increase by a factor of the square root of 2. This is because:

New Rate = k [a]0(2[b])1/2[c]2 = k [a]0[b]1/2 × √2 [c]2
= Rate × √2

Therefore, when the concentration of b is doubled, and a and c remain constant, the reaction rate will increase by a factor of √2 (approximately 1.414).

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Major groups of minerals include _____. oxides and carbonates ions and isotopes inorganics and halides silicates and magnetics

Answers

The  major    groups  of  minerals  includes: carbonate   ions  and oxides,  .  In  addition  to   this   three  groups   the    following   are   also  the  major   groups   of    minerals
native   elements
sulfate
sulfides
halides
silicate
nitrate       among   others  such   as  phosphate  and vanadate

oxides and carbonates, grad point..

What do you need to know describe the velocity of an object

Answers

Speed with a direction, and time.

Answer:

You need to know the speed, direction (displacement) and time to describe the velocity of an object.

Ethylene gas and steam at 320°c and atmospheric pressure are fed to a reaction process as an equimolar mixture. the process produces ethanol by the reaction: c2h4(g) + h2o(g) → c2h5oh(l)c2h4(g) + h2o(g) → c2h5oh(l) the liquid ethanol exits the process at 25°c. what is the heat transfer associated with this overall process per mole of ethanol produced?

Answers

The heat transfer formula is;
Q = m * c * Δ T >>>> (1)
where, Q is the heat transfer
m = mass  (gram)
c = the specific heat capacity (J/g)
Δ T = change in temperature
∵ we have one mole of Ethanol
∴ the weight of ethanol equals its molecular weight = (2*12)+(6*1)+(16) = 46 g
we will assume that the specific heat capacity of ethanol is 2.46 J/g (from google) 
ΔT = 25 - 320 = - 295 C
By substitution in (1)
∴ Q = 2.46 * 46 * (-295) = - 33382.2 J
Final answer:

Without specific enthalpy change (ΔH) values for the reactions in question, we cannot accurately calculate the heat transfer per mole of ethanol produced. However, if these values were provided, the general formula qp = ΔH(T2-T1)/T1*T2 could be used to determine this, where qp represents heat transfer at constant pressure, T1 and T2 are the initial and final temperatures respectively.

Explanation:

This question pertains to the field of thermochemistry and the role of heat transfer in chemical reactions. The process in question involves the transformation of ethylene gas and steam into ethanol, or C2H5OH. We would need the specific heat, or enthalpy change (ΔH), values for these reactions to calculate the heat transfer per mole of ethanol produced. Since these values haven't been provided, we can't provide a definite answer.

Generally, in such questions, when ΔH values and temperatures are given, one formula that can be applied is q_p = ΔH(T2-T1)/T1*T2 where T1 is initial temperature, T2 is final temperature and qp represents heat transfer at constant pressure.

This formula can be used to estimate the heat transfer associated with the process per mole of ethanol produced, once the ΔH value is known. It's also important to remember that if the reaction is exothermic (releases heat), the ΔH value would be negative, and if it's endothermic (absorbs heat), the ΔH value would be positive.

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A gas has a volume of 590 mL at a temperature of -55°C what volume will the gas occupy at 30°C

Answers

Using ideal gas formula (PV=nRT), you can conclude that volume directly related to the temperature. That means an increase in temperature will cause an increased volume too. Note that the temperature is using Kelvin, not Celsius. The calculation would be:

V1/T1= V2/T2
590ml / (-55+ 273)K = V2/ (30+273)K
V2= (590ml/ 218K) * 303K
V2= 820ml

The ph of a 0.55 m aqueous solution of hypobromous acid, hbro, at 25.0 °c is 4.48. what is the value of ka for hbro?

Answers

hbro  dissociate  as  follows
HBro--->  H+  +  BrO-
  Ka=  (H+)(BrO-)  /  HBro
 PH  =  -log (H+)
therefore (H+)  =  10^-4.48= 3.31  x10^-5
ka is  therefore= ( 3.31  x 10^-5)^2/0.55=1.99  x10^-9

number of moles in 3.70 x 10^-1 g of boron

Answers

Answer:

0.0342 mol

Explanation:

The molar mass of boron is 10.81 g/mol, that is, 1 mole of boron (6.02 × 10²³ molecules of boron) has a mass of 10.81 grams. This is the ratio that we will use to find the number of moles in 3.70 × 10⁻¹ g, using a conversion fraction.

3.70 × 10⁻¹ g B × (1 mol B / 10.81 g B) = 0.0342 mol B

Final answer:

To find the number of moles in Boron, you divide the given mass by the molar mass of Boron. Given the mass of Boron as 3.70 x 10^-1 g and the molar mass as 10.8 g/mol, the result is approximately 0.034 moles.

Explanation:

To find the number of moles in a sample, we use the formula: Moles = mass / molar mass. We already know the mass of boron, which is 3.70 x 10^-1 g. The average atomic mass of boron, considering its isotopes, is approximately 10.8 amu. Converting this into grams gives you 10.8 g/mol (since 1 amu = 1 g/mol).

Therefore, the number of moles of boron is calculated to be Moles = 3.70 x 10^-1 / 10.8 = approximately 0.034 moles.

Note that an atomic mass unit (amu) is basically the mass of one atom, on a scale where the carbon-12 atom is exactly 12.0 amu. However, no single boron atom weighs exactly 10.8 amu; 10.8 amu is the average mass of all boron atoms, considering the isotopes.

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Using the periodic table, choose the more reactive metal. (hint: reactivity of Ga > Al: reactivity of Zn > Ga) Pt or Ag

Answers

Answer:

Silver (Ag) is more reactive than platinum (Pt) :) hope this helps!!!

Explanation:

What mass of kbr (in grams) should you use to make 300.0 ml of a 1.50 m solution of kbr?

Answers

mass  of  kbr  which  should  use  to  make  300ml  of  a  1.50m  solution  of  kbr  is  calculated  as  follows

step  one  calculate  the  number  moles   of  Kbr
that  is   (1.50  x  300) /1000=0.45  moles
mass= molar  mass  x  moles
119  g/mol   ( molar  mass of  Kbr)  x  0.45 moles=  53.55g

Final answer:

To prepare a 300.0 mL of a 1.50 M KBr solution, you need 53.55 grams of KBr, calculated by multiplying the required moles (0.450 moles) by the molar mass of KBr (119.00 g/mol).

Explanation:Calculating the Mass of KBr for a Solution

To find the mass of KBr needed to make a 300.0 mL (0.300 L) of a 1.50 M solution, we apply the formula:

Molarity (M) = moles of solute / liters of solution

First, calculate the moles of KBr required:

Moles of KBr = Molarity × Volume in LitersMoles of KBr = 1.50 moles/L × 0.300 LMoles of KBr = 0.450 moles

Next, convert moles to grams using the molar mass of KBr (119.00 g/mol):

Mass of KBr = Moles of KBr × Molar Mass of KBrMass of KBr = 0.450 moles × 119.00 g/molMass of KBr = 53.55 grams

Therefore, you would need 53.55 grams of KBr to make a 300.0 mL of a 1.50 M KBr solution.

In a chemical reaction, it is determined that the equilibrium constant is 0.213. Which of the following is a correct statement regarding this reaction?
There are more products than reactants at equilibrium.


The reaction will continue until no reactant remains.


There are more reactants than products at equilibrium.


The reaction has stopped completely.

Answers

Answer: There are more reactants than products at equilibrium.

Explanation:

1) The equilibrium constant is defined as the ratio of the constant of reaction for the forward reaction divided by the constant of reaction for the reverse reaction.

2) If the constant of reacton for the forward reaction is greater than the constant of reaction for the reverse reaction, then the equilbrium constant is greater than 1 and the equilibrium is reached at a point where there are more products than reactants.

This is not the case given that the equilibrium constant is less than 1.

3) If the constant of reaction for the forward reaction is less than the constant of reaction for the reverse reaction, then the equilibrium constant is less than 1 and at equilibrium there will be more reactants than products.


This is the case given, since the equilibrium constant is 0.123.

Therefore, the answer is: there are more reactants than products at equilibrium.

Final answer:

The correct statement for a chemical reaction with an equilibrium constant of 0.213 is that there are more reactants than products at equilibrium.

Explanation:

Given that the equilibrium constant is 0.213 for a chemical reaction, we can make certain determinations about the state of the reaction at equilibrium. When the equilibrium constant (K) is less than 1, this generally means that the ratio of products to reactants at equilibrium is small and the reaction system favors the reactants. Therefore, the correct statement is that there are more reactants than products at equilibrium.

It is important to understand that when equilibrium is reached, the reaction has not stopped; rather, it is a dynamic state where the forward and reverse reactions continue at the same rate, maintaining constant concentrations of reactants and products. The idea that the reaction continues until no reactant remains is incorrect because a reaction at equilibrium does not favor complete conversion to products unless the equilibrium constant is significantly greater than 1.

describe the placement of the crucible lid on the crucible when heating the magnesium. Why is it important that this be done correctly?

Answers

Set the crucible's lid slightly off-center to allow air to enter while keeping the magnesium oxide from escaping.

What is a crucible lid?

A crucible is a cup-shaped piece of laboratory equipment used to keep chemical compounds contained while they are heated to extremely high temperatures.

Crucibles come in a variety of sizes and are usually packaged with a crucible cover (or lid).

Keep the lid on the crucible while cooling to prevent moisture from the atmosphere from interacting with the anhydrous salt, especially if the lab is humid. As a result, the mass of water will be too low.

The most important apparatus because it will be used to obtain the final precipitate, which will tell us how much salt is in the solution.

The lid is used to cover the crucible so that the heated precipitates do not oxidize when they come into contact with air.

Thus, it is important that the lid should be kept correctly.

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Identify element 3. EXPLAIN YOUR REASONING

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If you compare the different ionization levels of element 3, you will see that the first and second ionization energy is less when comparing it to the third, this means that this element has 2 valence electrons. In period three, as mentioned in the given, Magnesium has 2 valence electrons. So element 3 is MAGNESIUM.

Provide the structure of the major product which results from 1,4-addition of br2 to the diene shown below.

Answers

The image provided shows the diene that is used for this question. We are told that the major product of the reaction is the 1,4-addition product. The result is the addition of a bromine atom to the first carbon and the fourth carbon of the diene. However, Br₂ can also add to just one alkene of the diene in a 1,2-addition to get the other product shown in the image.

As the first bromine atom adds to one of the alkenes, it adds to the first carbon which leads to the formation of a carbocation. The carbocation can be a stable tertiary center at the 2 carbon of the diene, or the less stable secondary center of the 4 carbon. To addition to the 4-carbon has a higher activation barrier which, but the product has a lower energy than the 1,2-product. Therefore, the 1,4-addition is the thermodynamic product and will form at higher temperatures. The 1,2-product is the kinetic product that will form at lower temperatures.

What volume of a 0.25 m phosphoric acid solution is required to react completely with 1.0 l of 0.35 m sodium hydroxide?

Answers

The moles have to be equal. Always start with a balanced equation. This reaction is a double replacement.
The basic equation is
NaOH + H3PO4 ===> Na3PO4 + HOH

The balanced equation is.
3NaOH + H3PO4 ===> Na3PO4 + 3HOH

moles of NaOH = moles of H3PO4
mols of NaOH = molarity * Volume
molarity = 0.35 mol/L
Volume = 1.0 L
moles NaOH = 0.35 * 1 = 0.35 mols

Find the moles of H3PO4
For every mol of H3PO4 used, you require 3 mols of NaOH
3/1 = 0.35/x
3x = 0.35
x = 0.35/3
x = 0.1167 moles of H3PO4 needed for this reaction.

Now the volume needs to be calculated.
n = 0.1167
M = 0.25 mol/L
V = ??

Formula
M = n/V
V = n/M
V = 0.1157/0.25 
V = 0.467 L

Note: I merely copied the reaction given myself to the next line. I'm not copying from an outside source.

A gas sample has a volume of 178 mL at 0.00oC.The temperature is raised at constant pressure until the volume reaches 211 mL. What is the temperature of that gas sample at this volume?

Answers

V₁ = 178 mL                  - initial volume 
T₁ = 0 ⁰C = 273K          - initial temperature
V₂ = 211 mL                   - final volume
T₂ =?                              - final temperature

According to Charles's law when pressure is constant the Kelvin temperature and the volume will be directly related:

V₁/T₁=V₂/T₂

178/273=211/T₂

0.65=211/T₂

T₂=324K= 51⁰C

The temperature of the gas will be 324K or [tex]\rm \bold{51^\cdot C}[/tex] when volume reaches 211 mL.

Charle's law stated that the volume occupied by fixed amount of gas is directly proportional to the temperature,while  pressure is constant.

 [tex]\rm \bold{\frac{V_1}{T_1} =\frac{V_2}{T_2}}[/tex]

Where,

[tex]\rm \bold V_1[/tex] is initial volume = 178mL

[tex]\rm \bold {V_2}[/tex] is final volume = 211mL

[tex]\rm \bold{ T_1}[/tex] is initial temperature = [tex]\rm \bold{0.00^\cdot C}[/tex] = 273K

[tex]\rm \bold {T_2}[/tex] is final temperature = ?

Put the values,

[tex]\rm \bold{\frac{178}{273} =\frac{211}{T_2}}\\\\\rm \bold{T_2=324 K}[/tex]

Hence, we can conclude that the temperature of the gas will be 324K or [tex]\rm \bold{51^\cdot C}[/tex] when volume reaches 211 mL.

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A 42 kg sample of water absorbs 347 kJ of heat. If the water was initially at 23.2 ∘C, what is its final temperature?

Answers

The  final  temperature  if  the  water  was  initially  at  23.3  degrees  is calculated  as  using  Q =Mc  delta  T
Q(heat)=   347 Kj
M=mass(42 Kg)
C=specific  heat  capacity  of  water(  4.187 Kj/Kg/K)
delta  T  is  the  change  in  temperature

347  Kj =  42  Kg x  4.187  Kj/ Kg/K  x  delta  T
347Kj=  175.854  Kj/K  x  delta  T
divide both  side  by  175.854 Kj k
347kj/175.854 kjk=175.854/175.854  x  delta  T
1.973  = delta T
if  the  initial  temperature  is  23.2  and  delta  T  is  1.973  therefore  final  temperature  =  1.973  +23.2=25.173 degrees 
Whenever we deal with the problems for checking the amount of heat lost or gained(absorbed) by the fluid, we use the following equation:

[tex]Q = m * C_{p} * dT[/tex] --- (A)

Where,
Q = The amount of heat lost or gained(absorbed) by the fluid
m = Mass of the fluid
[tex]C_{p}[/tex] = Heat Capacity of the fluid
[tex]dT[/tex] = Change in Temperature = Final Temperature([tex]T_{f}[/tex]) - Initial Temperature([tex]T_{i}[/tex])

Data given:
Initial Temperature = [tex]T_{i}[/tex] = 23.2°C
The amount of heat absorbed by the water = 347 kJ
Mass of the water = m = 42 kg
Heat Capacity of water = [tex]C_{p}[/tex] = 4.184 kJ/kg°C
Final Temperature = [tex]T_{f}[/tex] = ?

Plug-in the values in equation (A)

(A) => 347 = 42 * 4.184 * ([tex]T_{f}[/tex] - 23.2)

=> [tex]T_{f}[/tex] ≈ 25.175°C

Ans: The final temperature of water  25.175°C

-i

What mass (in grams) of iron(iii) oxide contains 58.7 g of iron? iron(iii) oxide is 69.94 % iron by mass?

Answers

The percent composition  (%) of iron (Fe+3) in Fe2O3 equals:
Fe % = Atomic mass of Fe / (Molecular weight of Fe2O3)
∵ Atomic mass of Fe = 55.8 g/mol
and, the atomic mass of Oxygen is 16 g/mol
∴ percent of iron in Fe2O3 = [(2*55.8) / ((3*16) + (2*55.8))] *100 = 69.92 % >>> (1)
And if the mass of the iron is 58.7 g 
∴ mass of Fe2O3 = 58.7 * 100 / 69.92 = 83.95 g >>>> (2)
So, from (2), the mass of iron (III) oxide is 83.95 g
and, from (1), the iron III oxide is 69.92 % iron by mass not 69.94% 


A substance's percent composition basically reveals to you what number of grams of every constituent component you get per 100 g of said substance. 
For this situation, a percent composition of 
69.94% implies that for each 100 g of iron(III) oxide, 
Fe2O3, you get 69.94 g of iron.

So the solution for this problem would be: 58.7 g Fe = 100 g Fe2O3 / 69.94 g Fe = 83.93 g Fe2O3

is a measure of the quantity of matter in an object. A) Volume B) Mass C) Density D)Weight

Answers

Mass is a measure of the quantity of matter in an object

Answer:

Mass is a measure of the quantity of matter in an object

Explanation:

Which element is reduced in this reaction? 2cr(oh)3+3ocl−+4oh−→2cro4−2+3cl−+5h2o enter the chemical symbol of the element?

Answers

the answer is: Cl was reduced in this reaction
according to the balanced reaction equation, we can know that:
- as Cl in OCl^- is +1 
and Cl in Cl^- is -1
- and Cr in CrO4^-2 is +6
- and Cr in Cr(OH)3 is +3
∴ Cl went from +1 to -1 and was reduced, It means a reduction in charge.
& Cr went from +3 to +6 so it was oxidized.


In an oxidation-reduction reaction, what happens to the electrons in the reduction process?

Answers

one element will be reduced and the other will be oxidized 

Answer:

Electrons will be gained

A solution is prepared by dissolving 17.75 g sulfuric acid, h2so4, in enough water to make 100.0 ml of solution. if the density of the solution is 1.1094 g/ml, what is the molality?

Answers

Answer: The molality of solution is 1.94 m.

Explanation:

We are given:

Mass of sulfuric acid = 17.75 grams

Volume of solution = 100 mL

Density of solution = 1.1094 g/mL

To calculate the mass of solution, we use the equation:

[tex]Density=\frac{Mass}{Volume}[/tex]

Putting values in above equation, we get:

[tex]1.1094g/mL=\frac{\text{Mass of solution}}{100mL}[/tex]

[tex]\text{Mass of solution}=110.94g[/tex]

Mass of solvent = Mass of solution - Mass of solute

Mass of solvent = 110.94 - 17.75 = 93.19 g

To calculate the molality of solution, we use the equation:

[tex]Molality=\frac{m_{solute}\times 1000}{M_{solute}\times W_{solvent}\text{ in grams}}[/tex]

Where,

[tex]m_{solute}[/tex] = Given mass of solute [tex](H_2SO_4)[/tex] = 17.75 g

[tex]M_{solute}[/tex] = Molar mass of solute [tex](H_2SO_4)[/tex] = 98 g/mol

[tex]W_{solvent}[/tex] = Mass of solvent = 93.19 g

Putting values in above equation, we get:

[tex]\text{Molality of }H_2SO_4=\frac{17.75\times 1000}{98\times 93.19}[/tex]

[tex]\text{Molality of }H_2SO_4=1.94m[/tex]

Hence, the molality of solution is 1.94 m.

Final answer:

To calculate the molality of the sulfuric acid solution, we convert the volume to mass, find the number of moles of sulfuric acid, and divide by the mass of the solvent in kilograms.

Explanation:

To calculate the molality of a solution, we need to find the number of moles of solute and the mass of the solvent.

In this case, we are given the mass of sulfuric acid (17.75 g) and the volume of the solution (100.0 ml). First, we need to convert the volume to mass by multiplying it by the density of the solution (1.1094 g/ml). 100.0 ml x 1.1094 g/ml = 110.94 g.

To find the number of moles of sulfuric acid, we divide the mass by the molar mass of sulfuric acid (98.09 g/mol). 17.75 g / 98.09 g/mol ≈ 0.1808 mol.

Finally, we can calculate the molality by dividing the moles of solute by the mass of the solvent in kilograms. 0.1808 mol / 0.11094 kg = 1.63 mol/kg.

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