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2 years ago

What will the volume be of a soltuion created using 120 ml of 4.5 M stock solution if the final molarity needs to be 2.00 M

Chemistry

1 answer:

Troyanec [42]2 years ago

3 0

Answer:

We need 540 mmoles of stock solution and complete to 270 mL of volume.

Explanation:

In order to determine the volume or concentration at diluted solution we apply this formula:

Dil volume . Dil concentration = Conc volume . Conc concentration

Stock solution is always, the concentrated.

Let's replace with data given:

Dil. volume . 2 M = 120 mL . 4.5 M

Diluted volume = (120 mL . 4.5M) / 2M

Diluted volume = 270 mL

This problem can be also solved by rule of three:

1 mL of stock solution contains 4.5 mmoles

120 mL of stock solution contain (120 mL . 4.5 mmoles) / 1mL = 540 mmoles

This mmoles of stock solution are also contained at the diluted

If 2 mmoles are contained in 1mL of diluted solution

540 mmoles must be contained in (540 mmol . 1 mL) / 2 mmol = 270 mL

We need 540 mmoles of stock solution and complete to 270 mL of volume.

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3 years ago

An element has an atomic number of 76. The number of protons and electrons in a neutral atom of the element are ____.

dmitriy555 [2]

Answer:

76 protons 76 electrons

Explanation:

The atomic number in a element is equal to the elements protons and electrons. In this case if the atomic number is 76 the number of protons and electrons would also be 76.

Hope this helps.

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2 years ago

If 4.50 g of HCl are reacted with 15.00 g of Caco, according to the following balanced chemical equation, calculate the theoreti

Tom [10]

Answer: HCl is the limiting reactant and the theoretical yield is 2.72 g of CO2. If the actual yield was 2.50 g then, the percent yield is 92.0% when rounding off is done only for the final answer.

Further Explanation:

In order to determine the theoretical yield and the percent yield of CO2, the following steps must be done:

Determine the limiting reactant. This is the reactant that will determine the amount of CO2 that will actually form.
Determine the theoretical yield for CO2 when the limiting reactant is used.
Get the percent yield by getting the ratio of the actual yield stated in the problem and the calculated theoretical yield multiplied by 100.

Determining the Limiting Reactant

The Limiting Reactant (LR) will produce fewer moles of the products. To check which of the reactants HCl or CaCO3 is the LR, we do dimensional analysis:

For HCl:

$moles\ CO_{2}\ = (4.50\ g\ HCl)\(\frac{1\ mol\ HCl}{36.46094\ g})( \frac{1\ mol\ CO_{2} }{2\ mol\ HCl}) \\moles\ CO_{2}\ =\ 0.0617098$

For CaCO3:

$moles\ of\ CO_{2}\ = (15.00\ g\ CaCO_{3})\ (\frac{1\ mol\ CaCO_{3} }{100.0869\ g\ CaCO_{3} })\ (\frac{1\ mol\ CO_{2} }{1\ mol\ CaCO_{3} })\\moles\ of\ CO_{2}\ = \ 0.1499$

Since HCl produces fewer moles of CO2, then it is the limiting reactant. We will use the given amount to determine the theoretical yield for CO2.

Determining the Theoretical Yield

From Step 1, we know that 0.0617098 moles of CO2 will be produced. We will just convert this to grams.

$grams\ CO_{2}\ =\ (0.0617098\ mol\ CO_{2}) (\frac{44.01\ g\ CO_{2}}{1\ mol\ CO_{2}})\\grams\ CO_{2}\ =\ 2.71585$

Since the answer only requires 3 significant figures, the final answer is 2.72 grams CO2.

Determining the Percent Yield

Dividing the actual yield by the theoretical yield will give us the percent yield, which is an indicator of how efficient the experiment or the method used was.

From the problem, the actual yield was 2.50 g, hence, the percent yield is:

$percent\ yield\ of\ CO_{2}\ = (\frac{2.50\ g}{2.71585\ g}) (100)\\percent\ yield\ of\ CO_{2}\ = 92.05221$

Rounding off to three significant figures, the percent yield is 92.0%. This suggests that the method used is somewhat efficient in producing CO2.

Learn More

Learn More about Limiting Reactant brainly.com/question/7144022
Learn More about Excess Reactant brainly.com/question/6091457
Learn More about Stoichiometry brainly.com/question/9743981

Keywords: stoichiometry, theoretical yield, actual yield

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3 years ago

Halp balance plez (⊙◡⊙)

grandymaker [24]

Answer: SnO2 + 2 H2 = Sn + 2 H2O

Explanation: I used a balance equation website. It's called WebQC if you want to check it out for future help.

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3 years ago

Kit wants to see what happens to chocolate chips if they are placed in a bowl and heated in the microwave. Which is likely the m

kvasek [131]

B. When melted, the chocolate will take the shape of the bowl.

Explanation:

The chocolate chips are heated in the bowl, they will assume the shape of the bowl or container they are placed in.

They simply undergo a phase change from solids to liquids.
Solids generally have fixed volume with their rigid shapes.
Liquids and gases takes up the shape of the container they are placed in.
Baring no loss of chocolate, the weight will remain the same because weight is function of mass and gravity. Gravity will remain the same, and the amount of matter, the mass will also be the same.

Learn more:

Phase change brainly.com/question/1875234

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3 years ago