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3 years ago

13. If a chemist has 12.3 moles of N H 03, what is the mass of the sample?

Chemistry

1 answer:

user100 [1]3 years ago

3 0

Answer:

209.4831 g

Explanation:

number of moles × molar mass = mass of substance in g

12.3 × ( 14.0067 + 1.00484 × 3 ) = 209.4831 g

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Which element has 13 protons and 8 neutrons?

WINSTONCH [101]

Answer:

only thing close I can see would be aluminun

Explanation:

atomic number of 13 and 8 2nd electrons in its shell.

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3 years ago

Read 2 more answers

What is the pH of this solution?

Vesnalui [34]

Answer:

pH = 11.216.

Explanation:

Hello there!

In this case, according to the ionization of ammonia in aqueous solution:

$NH_3+H_2O\rightleftharpoons NH_4^++OH^-$

We can set up its equilibrium expression in terms of x as the reaction extent equal to the concentration of each product at equilibrium:

$Kb=\frac{[NH_4^+][OH^-]}{[NH_3]} \\\\1.80x10^{-5}=\frac{x*x}{0.150-x}$

However, since Kb<<<1 we can neglect the x on bottom and easily compute it via:

$1.80x10^{-5}=\frac{x*x}{0.150}\\\\x=\sqrt{1.80x10^{-5}*0.150}=1.643x10^{-3}M$

Which is also:

$[OH^-]=1.643x10^{-3}M$

Thereafter we can compute the pOH first:

$pOH=-log(1.643x10^{-3}M)\\\\pOH=2.784$

Finally, the pH turns out:

$pH=14-2.784\\\\pH=11.216$

Regards!

5 0

3 years ago

5. What is the partial pressure of the remaining gas, if the total is 384 torr 2

alexgriva [62]

Answer: 83.11 torr

Explanation:

According to Dalton's Law of partial pressure, the total pressure of a mixture of gases is the sum of the pressure of each individual gas.

i.e Ptotal = P1 + P2 + P3 + .......

In this case,

Ptotal = 384 torr

P1 = 289 torr

P2 = 11.89 torr

P3 = ? (let the partial pressure of the remaining gas be Z)

Ptotal = P1 + P2 + Z

384 torr = 289 torr + 11.89 torr + Z

384 torr = 300.89 torr + Z

Z = 384 torr - 300.89 torr

Z = 83.11 torr

Thus, the partial pressure of the remaining gas is 83.11 torr.

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3 years ago

In the equation 2KCIO3 → 2KCI + 302, how many moles of oxygen are produced when 12.61 mol of

Zepler [3.9K]

Answer:

A 19

Explanation:

2 mole of KClO3 produces 3 mole of O3

2 : 3

1 : 3/2

12.61 : 3/2 × 12.61

12.61 : 18.9

12.61 mole of KClO3 produces 18.9mole of O2.

7 0

3 years ago

A 4.36 g sample of an unknown alkali metal hydroxide is dissolved in 100.0 ml of water. an acid-base indicator is added and the

Fofino [41]

Answer:

(a) $102.6g/mol$

(b) Rubidium

Explanation:

Hello,

This titration is carried out by assuming that the volume of base doesn't have a significant change when the mass is added, thus, we state the following data a apply the down below formula to compute the molarity of the base solution:

$V_{base}=0.1L; M_{acid}=2.5M, V_{acid}=0.017L\\V_{base}M_{base}=V_{acid}M_{acid}$

Solving for the molarity of base we've got:

$M_{base}=\frac{M_{acid}*V_{acid}}{V_{base}}=\frac{2.50M*0.017L}{0.1L} =0.425M=0.425mol/L$

Now, we can compute the moles of the base as:

$n_{base}=0.425mol/L*0.1L=0.0425mol$

(a) Now, one divides the provided mass over the previously computed moles to get the molecular mass of the unknown base:

$\frac{4.36g}{0.0425mol} =102.6g/mol$

(b) Subtracting the atomic mass of oxygen and hydrogen, the metal's atomic mass turns out into:

$102.6g/mol-16g/mol-1g/mol=85.6g/mol$

So, that atomic mass dovetails to the Rubidium's atomic mass.

Best regards.

8 0

3 years ago

13. If a chemist has 12.3 moles of N H 03, what is the mass of the sample?​

13. If a chemist has 12.3 moles of N H 03, what is the mass of the sample?