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2 years ago

13

Which of the following is a source of chemical energy commonly used by humans? A. water flowing in a river B. a bicycle C. a san

dwich D. turning on a lightswitch

1 answer:

ziro4ka [17]2 years ago

7 0

Answer:

Option C sandwich is the correct option

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10. The molar mass of an unknown gas was measured by an effusion experiment. It was found that it took 63 s for the gas to effus

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2 years ago

How do you test for carbon dioxide ?? Explain

g100num [7]

Answer:

Carbon dioxide reacts with calcium hydroxide solution to produce a white precipitate of calcium carbonate

Explanation:

. Limewater is a solution of calcium hydroxide. If carbon dioxide is bubbled through limewater, the limewater turns milky or cloudy white

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2 years ago

6) A student measures out 96.21 g of sulfur for an experiment. How many moles of Sulfur are in this

barxatty [35]

Atomic mass of Sulfur = 32g

32g of Sulfur is one mole.

1g of Sulfur is $\frac{1}{32} moles$

96.21g of Sulfur is $\frac{96.21}{32} moles=> 3moles(appx)$

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3 years ago

Read 2 more answers

We have two surfaces A and B where same amount of Force is acting. Area of Surface A is greater than Area of Surface B. which of

Phoenix [80]

Answer:

Pressure on Surface A > Pressure on Surface B

Explanation:

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re on Surface B > Pressure on Surface A

7 0

3 years ago

g When aqueous solutions of and are mixed, a solid forms. Determine the mass of solid formed when 140.7 mL of 0.1000 M is mixed

solong [7]

The question is incomplete, the complete question is:

When aqueous solutions of NaCl and $Pb(NO_3)_2$ are mixed, a solid forms. Determine the mass of solid formed when 140.7 mL of 0.1000 M NaCl is mixed with an excess of an aqueous solution of

<u>Answer:</u> The mass of lead chloride produced is 1.96 g

<u>Explanation:</u>

Molarity is defined as the amount of solute expressed in the number of moles present per liter of solution. The units of molarity are mol/L. The formula used to calculate molarity:

$\text{Molarity of solution}=\frac{\text{Moles of solute}\times 1000}{ \text{Volume of solution (mL)}}$ .....(1)

Given values:

Molarity of NaCl = 0.1000 M

Volume of the solution = 140.7 mL

Putting values in equation 1, we get:

$0.1000=\frac{\text{Moles of NaCl}\times 1000}{140.7}\\\\\text{Moles of NaCl}=\frac{0.1000\times 140.7}{1000}=0.01407mol$

The chemical equation for the reaction of NaCl and lead nitrate follows:

$Pb(NO_3)_2(aq)+2NaCl(aq)\rightarrow PbCl_2(s)+2NaNO_3(aq)$

By the stoichiometry of the reaction:

If 2 moles of NaCl produces 1 mole of lead chloride

So, 0.01407 moles of NaCl will produce = $\frac{1}{2}\times 0.01407=0.007035mol$ of lead chloride

The number of moles is defined as the ratio of the mass of a substance to its molar mass.

The equation used is:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ......(2)

Molar mass of lead chloride = 278.1 g/mol

Plugging values in equation 2:

$\text{Mass of lead chloride}=(0.007035mol\times 278.1g/mol)=1.96g$

Hence, the mass of lead chloride produced is 1.96 g

8 0

3 years ago