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scoundrel [369]

3 years ago

7

Greenhouse gases make up what percentage of Earth's atmosphere? A. less than 1% B. between 1% and 5% C. between 5% and 20% D. ov

er 20%

2 answers:

Andrew [12]3 years ago

7 0

The correct answer is C

Dmitrij [34]3 years ago

3 0

Hello there, the correct answer is:

C.

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How long is 5 half lives if the half life is 2.6 hours? Remember to round to the correct number of significant figures and use u

Dmitry [639]

Answer:

$\Delta t = 13\,h$

Explanation:

Half time is period required to desintegrating the half of the initial number of atoms. Then, the total time is:

$\Delta t = 5\cdot (2.6\,h)$

$\Delta t = 13\,h$

3 0

3 years ago

What is the mass in grams of 85.32 mL of blood plasma with a density of 1.03 g/mL

sveticcg [70]

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3 0

3 years ago

What continent has no deserts

nevsk [136]

Answer:

Antarctica.

Explanation:

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4 0

3 years ago

A 0.8870 g sample of a mixture of NaCl and KCl is dissolved in water, and the solution is then treated with an excess of AgNO3 t

bagirrra123 [75]

Answer : The percent by mass of NaCl and KCl are, 92.22 % and 7.78 % respectively.

Explanation :

As we know that when a mixture of NaCl and KCl react with excess $AgNO_3$ then the silver ion react with the chloride ion in both NaCl and KCl to form silver chloride.

Let the mass of NaCl be, 'x' grams and the mass of KCl will be, (0.8870 - x) grams.

The molar mass of NaCl and KCl are, 58.5 and 74.5 g/mole respectively.

First we have to calculate the moles of NaCl and KCl.

$\text{Moles of }NaCl=\frac{\text{Mass of }NaCl}{\text{Molar mass of }NaCl}=\frac{xg}{58.5g/mole}=\frac{x}{58.5}moles$

$\text{Moles of }KCl=\frac{\text{Mass of }KCl}{\text{Molar mass of }KCl}=\frac{(0.8870-x)g}{74.5g/mole}=\frac{(0.8870-x)}{74.5}moles$

As, each mole of NaCl and KCl gives one mole of chloride ions.

So, moles of chloride ions in NaCl = $\frac{x}{58.5}moles$

Moles of chloride ions in KCl = $\frac{(0.8870-x)}{74.5}moles$

The total moles of chloride ions = $\frac{x}{58.5}moles+\frac{(0.8870-x)}{74.5}moles$

Now we have to calculate the moles of AgCl.

As we know that, this amount of chloride ion is same as the amount chloride ion present in the AgCl precipitate. That means,

Moles of AgCl = Moles of chloride ion = $\frac{x}{58.5}moles+\frac{(0.8870-x)}{74.5}moles$

Now we have to calculate the moles of AgCl.

The molar mass of AgCl = 143.32 g/mole

$\text{Moles of }AgCl=\frac{\text{Mass of }AgCl}{\text{Molar mass of }AgCl}=\frac{2.142g}{143.32g/mole}=0.0149moles$

Now we have to determine the value of 'x'.

Moles of AgCl = $\frac{x}{58.5}moles+\frac{(0.8870-x)}{74.5}moles$

0.0149 mole = $\frac{x}{58.5}moles+\frac{(0.8870-x)}{74.5}moles$

By solving the term, we get the value of 'x'.

$x=0.818g$

The mass of NaCl = x = 0.818 g

The mass of KCl = (0.8870 - x) = 0.8870 - 0.818 = 0.069 g

Now we have to calculate the mass percent of NaCl and KCl.

$\text{Mass percent of }NaCl=\frac{\text{Mass of }NaCl}{\text{Total mass of mixture}}\times 100=\frac{0.818g}{0.8870g}\times 100=92.22\%$

$\text{Mass percent of }KCl=\frac{\text{Mass of }KCl}{\text{Total mass of mixture}}\times 100=\frac{0.069g}{0.8870g}\times 100=7.78\%$

Therefore, the percent by mass of NaCl and KCl are, 92.22 % and 7.78 % respectively.

3 0

3 years ago

If you have 3.01 E24 molecules of CO, how many moles of CO do you have?

MA_775_DIABLO [31]

Answer: 5moles

Explanation:

1mole of a substance contains 6.02x10^23 molecules.

Then, 1mole of CO also contains 6.02x10^23 molecules.

If 1 mole of CO2 contains 6.02x10^23 molecules, it means Xmol of CO contains 3.01 E24 ie 3.01x10^24 molecules

Xmol of CO = 3.01x10^24 / 6.02x10^23

Xmol = 5moles

5 0

4 years ago