All categories

3 years ago

Suppose you were making 100.0 mL of a solution that is 0.040 M KCl. What mass of KCl should you weigh to make this solution?

Chemistry

1 answer:

scZoUnD [109]3 years ago

3 0

Answer:

mass = 0.2982 grams

Explanation:

Given that;

volume = 100.0 mL = 0.1 L

Molarity =0.040 M

Since Molarity = $\frac{no of moles }{volume}$

$0.040 M = \frac{x}{0.1}$

(x) no of moles = 0.040 × 0.1

= 0.004 moles

Also; to calculate the mass of KCl should you weigh to make this solution;

we have;

no of moles = $\frac{mass}{molar mass}$

molar mass of KCl = 74.55 g/mol

∴

0.004 moles = $\frac{mass}{74.55g/mol}$

mass = 0.004 moles * 74.55 $\frac{g}{mol}$

mass = 0.2982 grams

Hence, the mass of KCl should you weigh to make this solution is 0.2982 grams

You might be interested in

A student reacts 5.0 g of sodium with 10.0 g of chlorine and collect 5.24 g of sodium chloride. What is the percent yield of thi

Ede4ka [16]

Answer: The percent yield of this combination reaction is 41.3 %

Explanation : Given,

Mass of $Na$ = 5.0 g

Mass of $Cl_2$ = 10.0 g

Molar mass of $Na$ = 23 g/mol

Molar mass of $Cl_2$ = 71 g/mol

First we have to calculate the moles of $Na$ and $Cl_2$ .

$\text{Moles of }Na=\frac{\text{Given mass }Na}{\text{Molar mass }Na}$

$\text{Moles of }Na=\frac{5.0g}{23g/mol}=0.217mol$

and,

$\text{Moles of }Cl_2=\frac{\text{Given mass }Cl_2}{\text{Molar mass }Cl_2}$

$\text{Moles of }Cl_2=\frac{10.0g}{71g/mol}=0.141mol$

Now we have to calculate the limiting and excess reagent.

The balanced chemical equation will be:

$2Na+Cl_2\rightarrow 2NaCl$

From the balanced reaction we conclude that

As, 2 mole of $Na$ react with 1 mole of $Cl_2$

So, 0.217 moles of $Na$ react with $\frac{0.217}{2}=0.108$ moles of $Cl_2$

From this we conclude that, $Cl_2$ is an excess reagent because the given moles are greater than the required moles and $Na$ is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of $NaCl$

From the reaction, we conclude that

As, 2 mole of $Na$ react to give 2 mole of $NaCl$

So, 0.217 mole of $HCl$ react to give 0.217 mole of $NaCl$

Now we have to calculate the mass of $NaCl$

$\text{ Mass of }NaCl=\text{ Moles of }NaCl\times \text{ Molar mass of }NaCl$

Molar mass of $NaCl$ = 58.5 g/mole

$\text{ Mass of }NaCl=(0.217moles)\times (58.5g/mole)=12.7g$

Now we have to calculate the percent yield of this reaction.

Percent yield = $\frac{\text{Actual yield}}{\text{Theoretical yield}}\times 100$

Actual yield = 5.24 g

Theoretical yield = 12.7 g

Percent yield = $\frac{5.24g}{12.7g}\times 100$

Percent yield = 41.3 %

Therefore, the percent yield of this combination reaction is 41.3 %

4 0

3 years ago

An ideal gas differs from a real gas in that the molecules of an ideal gas __________. a have a molecular weight of zero b have

Rasek [7]

An ideal gas differs from a real gas in that the molecules of an ideal gas have no attraction for one another.
An ideal gas is defined as one in which collisions between atoms or molecules are perfectly elastic and in which there are no inter-molecular attractive forces. A real gas on the other hand is a gas that does not behave as an ideal gas due to interactions between gas molecules. Particles in a real gas have a real volume since real gases are made up of molecules or atoms that typically take up some space even though they are extremely small.

4 0

3 years ago

In your own words, describe the purpose of using a chemical equation.<br><br> PLEASEEEE HURRY

Soloha48 [4]

Answer:

Hey mate, here is your answer. Hope it helps you.

Explanation:

To show how substances in a chemical reaction interact and to keep track of all elements and the number of atoms in each element on each side of the equation.The purpose of writing a balanced chemical equation is to know: the reactants (starting material) and products (end results) that occur. the ratios in which they react so you can calculate how much reactants you need and how much products can be formed.

5 0

3 years ago

Which statement describes the condition in which diamonds form?

eduard

I think it's A but it might be different from your school and mine

4 0

3 years ago

Read 2 more answers

Describe the particle that is emitted during alpha decay. How do you think an atom changes when it undergoes alpha decay?

weqwewe [10]

Answer:

Helium nuclei is emitted during alpha decay.

Explanation:

Alpha radiations are emitted as a result of radioactive decay. The atom emit the alpha particles consist of two proton and two neutrons. Which is also called helium nuclei. When atom undergoes the alpha emission the original atom convert into the atom having mass number 4 less than and atomic number 2 less than the starting atom.

Properties of alpha radiation:

Alpha radiations can travel in a short distance.

These radiations can not penetrate into the skin or clothes.

These radiations can be harmful for the human if these are inhaled.

These radiations can be stopped by a piece of paper.

Example:

₉₂U²³⁸ → ₉₀Th²³⁴ + ₂He⁴ + energy

8 0

2 years ago