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3 years ago

How many grams of the parent isotope are left in the sample after three half lives?

Chemistry

1 answer:

pochemuha3 years ago

5 0

After 3 half-lives, 125 grams of the parent isotope will remain.

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What mass of K2SO4 would you measure out to prepare 550 ml of a 0.76 M solution

Nikolay [14]

The molecular weight of K2SO4 is 174.26 g/mole. The mass of K2SO4 required to make this solution is calculated in the following way.
550mL * (0.76mole/1000mL) * (174.26g/mole) = 72.84gram
I hope this helps.

5 0

3 years ago

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6. An environmental chemist needs a carbonate buffer of pH 10.00 to study the effects of acid rain on limestone-rich soils. To p

pishuonlain [190]

Answer:

[Na₂CO₃] = 0.094M

Explanation:

Based on the reaction:

HCO₃⁻(aq) + H₂O(l) ↔ CO₃²⁻(aq) + H₃O⁺(aq)

It is possible to find pH using Henderson-Hasselbalch formula:

pH = pka + log₁₀ [A⁻] / [HA]

Where [A⁻] is concentration of conjugate base, [CO₃²⁻] = [Na₂CO₃] and [HA] is concentration of weak acid, [NaHCO₃] = 0.20M.

pH is desire pH and pKa (10.00) is -log pka = -log 4.7x10⁻¹¹ = 10.33

Replacing these values:

10.00 = 10.33 + log₁₀ [Na₂CO₃] / [0.20]

[Na₂CO₃] = 0.094M

5 0

3 years ago

In some regions of the world, forests are cut down and then burned to create room for farmland. How might this local environment

UkoKoshka [18]

The answer is D.

Explanation

Without trees, no carbon dioxide will be released into the air. It would not raise oxygen levels, and it wouldn’t effect rising sea levels.

6 0

3 years ago

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In the Haber reaction, patented by German chemist Fritz Haber in 1908, dinitrogen gas combines with dihydrogen gas to produce ga

VashaNatasha [74]

The question is incomplete, complete question is :

In the Haber reaction, patented by German chemist Fritz Haber in 1908, dinitrogen gas combines with dihydrogen gas to produce gaseous ammonia. This reaction is now the first step taken to make most of the world's fertilizer. Suppose a chemical engineer studying a new catalyst for the Haber reaction finds that 348 liters per second of dinitrogen are consumed when the reaction is run at 205°C and 0.72 atm. Calculate the rate at which ammonia is being produced.

Answer:

The rate of production of ammonia is 217.08 grams per second.

Explanation:

$N_2+3H_2\rightarrow 2NH_3$

Volume of dinitrogen used in a second = 348 L

Temperature of the gas = T = 205°C = 205+273 K = 478 K

Pressure of the gas = P = 0.72 atm

Moles of dinitrogen = n

$n=\frac{PV}{RT}=\frac{0.72 atm\times 348 L}{0.0821 atm L/mol K\times 478 K}=6.385 mol$

According to reaction, 1 mole of dinitriogen gives 2 mole of ammonia.Then 6.385 moles of dinitrogen will give:

$\frac{2}{1}\times 6.385 mol=12.769 mol$

Mass of 12.769 moles of ammonia;

12.769 mol 17 g/mol = 217.08 g

217.08 grams of ammonia is produced per second.So, the rate of production of ammonia is 217.08 grams per second.

6 0

3 years ago

What is the percent error if the measured value is 30.0 g and the accepted value is 32.0 g?

JulsSmile [24]

Answer:6.25

Explanation:

3 0

3 years ago