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3 years ago

PLEASE HELP NOW! i need help

Chemistry

2 answers:

vladimir1956 [14]3 years ago

7 0

N is going to equal 0.82

never [62]3 years ago

5 0

Answer:

0.82 mol of gas

Explanation:

pv=nRT

(0.7 atm)(30L) = n (0.0817 L atm/mol K) (315 K)

n = 0.82 mol

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In a unimolecular reaction with seven times as much starting material as product at equilibrium, what is the value of keq?

Kitty [74]

K_eq = 0.14

The chemical equation is

A ⇌ B

The equilibrium constant expression is

K_eq = [B]/[A]

If [A] = 7[B]

K_eq = [B]/{7[B]}= 1/7 = 0.14

6 0

4 years ago

Starting with 9.3 moles of O2, how many moles of H2S will be needed and how many moles of SO2 will be produced in the following

tensa zangetsu [6.8K]

Answer: The amount of hydrogen sulfide needed is 6.2 moles and amount of sulfur dioxide gas produced is 6.2 moles

Explanation:

We are given:

Moles of oxygen gas = 9.3 moles

The chemical equation for the reaction of oxygen gas and hydrogen sulfide follows:

$2H_2S+3O_2\rightarrow 2SO_2+2H_2O$

For hydrogen sulfide:

By Stoichiometry of the reaction:

3 moles of oxygen gas reacts with 2 moles of hydrogen sulfide

So, 9.3 moles of oxygen gas will react with = $\frac{2}{3}\times 9.3=6.2mol$ of hydrogen sulfide

For sulfur dioxide:

By Stoichiometry of the reaction:

3 moles of oxygen gas produces 2 moles of sulfur dioxide

So, 9.3 moles of oxygen gas will produce = $\frac{2}{3}\times 9.3=6.2mol$ of sulfur dioxide

Hence, the amount of hydrogen sulfide needed is 6.2 moles and amount of sulfur dioxide gas produced is 6.2 moles

7 0

3 years ago

A volume of 500.0 mL of 0.160 M NaOH is added to 585 mL of 0.200 M weak acid ( K a = 1.28 × 10 − 5 ) . What is the pH of the res

Hitman42 [59]

Answer : The pH of the resulting buffer is, 5.22

Explanation : Given,

$K_a=1.28\times 10^{-5}$

First we have to calculate the moles of $NaOH\text{ and }HA$

$\text{Moles of }NaOH=\text{Concentration of }NaOH\times \text{Volume of solution}}=0.160M\times 0.500L=0.08mol$

and,

$\text{Moles of }HA=\text{Concentration of }HA\times \text{Volume of solution}}=0.200M\times 0.585L=0.117mol$

The balanced chemical reaction is:

$HA+(aq)+OH^-(aq)\rightarrow H_2O(l)+A^-(aq)$

Moles of HA left = 0.117 mol - 0.08 mol = 0.037 mol

Moles of $A^-$ = 0.08 mol

The expression used for the calculation of $pK_a$ is,

$pK_a=-\log (K_a)$

Now put the value of $K_a$ in this expression, we get:

$pK_a=-\log (1.28\times 10^{-5})$

$pK_a=5-\log (1.28)$

$pK_a=4.89$

Now we have to calculate the pH of buffer.

Using Henderson Hesselbach equation :

$pH=pK_a+\log \frac{[Salt]}{[Acid]}$

$pH=pK_a+\log \frac{[A^-]}{[HA]}$

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

$pH=4.89+\log (\frac{0.08}{0.037})$

$pH=5.22$

Thus, the pH of the resulting buffer is, 5.22

5 0

4 years ago

What is the molarity of a solution made by dissolving 50.0 g of HBr in enough water to make 600. mL of solution?

Minchanka [31]

Answer:

1.03M

Explanation:

mass/molar mass = moles of solution

50 g / (80+1) = 0.617 mol HBr

molarity*volume = moles

M*0.600 L = 0.617 mol

M = 0.617/0.600 = 1.03 M

3 0

3 years ago

The molar mass of the compound was found to be 30.069 g/mol. what is the molecular formula? express your answer as a chemical fo

kodGreya [7K]

For us to accurately determine what compound this is, additional info must be given. However I can suggest two compounds which have molecular mass of about 30.07 g/mol.

1. It could be NO or nitric oxide.

The molecular mass is 16 + 14= 30 g/mol

But if we search the exact weight, it is 30.01 g/mol

2. It could also be (CH3)2 or ethane.

The molecular mass is 2*12+ 6*1= 30 g/mol

But if we search the exact weight, it is 30.07 g/mol.

So we could say it more likely to to be (CH3)2

6 0

4 years ago