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3 years ago

What is the molarity of a solution that contains 1.78 moles of KNO3 dissolved in 2.50L of water?

Chemistry

1 answer:

Alexxandr [17]3 years ago

4 0

Answer:

molarity= 0.712M

Explanation:

From n=CV

n=1.78, C=?, V= 2.5L

1.78=C×2.5

C= 0.712M

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calculation check:

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3 years ago

Explain how you would convert the moles of a compound to the made (grams) of the same compound

Oduvanchick [21]

Answer:

see notes below

Explanation:

The mole is the mass of substance containing 1 Avogadro's Number of particles. That is, 1 mole substance = 1 formula weight. For elements, 1 mole weight is equal to the atomic weight expressed as grams. For molecules, 1 mole weight is equal to the molecular weight expressed as grams.

1 mole = 1 formula weight

Moles to Grams and Grams to Moles

Grams => Moles

Given grams, moles = mass given / formula weight

*Ask the question => How many formula weights are there in the given mass? => Results is always moles.

Moles => Grams

Given moles, grams = moles given X formula weight

*Summary

Grams to Moles => divide by formula weight

Moles to Grams => multiply by formula weight

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3 years ago

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3 years ago

Read 2 more answers

6. A 25.0-mL sample of potassium chloride solution was found to have a mass of 25.225 g.

Morgarella [4.7K]

Answer:

6. a. 5.53 (m/m) %; b. 0.7490M

7. 0.156M

Explanation:

6. In the solution of KCl, there are 1.396g of KCl in 25.225g of solution. As mass/mass percent is:

Mass solute / Mass solution * 100

The mass/mass percent of KCl is:

a. 1.396g KCl / 25.225g solution * 100

5.53 (m/m) %

b. Molarity is moles of solute per liters of solution:

Moles KCl -Molar mass: 74.55g/mol-:

1.396g KCl * (1mol / 74.55g) = 0.018726 moles KCl

Volume in liters: 25mL = 0.025L

Molarity:

0.018726 moles KCl / 0.025L = 0.7490M

7. 0.90% means 0.90g of NaCl in 100g of solution:

Moles NaCl -Molar mass: 58.44g/mol-:

0.90g NaCl * (1mol / 58.44g) = 0.0154 moles NaCl

Volume in Liters:

100g * (1mL / 1.01g) = 99mL = 0.099L

Molarity:

0.0154 moles NaCl / 0.099L =

0.156M

4 0

2 years ago