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3 years ago

Counting atoms worksheet

Chemistry

1 answer:

MakcuM [25]3 years ago

7 0

Answer: if you are looking for a worksheet go to teachers pay s teachers or Pinterest

Explanation: these are very reliable sources to find good worksheets

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What are the mole fraction and the mass percent of a solution made by dissolving 0.21 g KBr in 0.355 L water? (d = 1.00 g/mL.) m

IRISSAK [1]

Answer:

Mol fraction H2O = 0.99991

Mol fraction KBr = 0.00009

mass % KBr = 0.059 %

mass % H2O = 99.941 %

Explanation:

Step 1: Data given

Mass of KBr = 0.21 grams

Molar mass KBr = 119 g/mol

Volume of water = 355 mL

Density of water = 1.00 g/mL

Molar mass water = 18.02 g/mol

Step 2: Calculate mass water

Mass water = 355 mL * 1g /mL

Mass water = 355 grams

Step 3: Calculate moles water

Moles water = mass water / molar mass water

Moles water = 355 grams / 18.02 g/mol

Moles water = 19.7 moles

Step 4: Calculate moles KBr

Moles KBr = 0.21 grams / 119 g/mol

Moles KBr = 0.00176 moles

Step 5: Calculate total moles

Total moles = 19.7 moles + 0.00176 moles

Total moles = 19.70176 moles

Step 6: Calculate mol fraction

Mol fraction H2O = 19.7 moles / 19.70176 moles

Mol fraction H2O = 0.99991

Step 7: Calculate mol fraction KBr

Mol fraction KBr = 0.00176 / 19.70176

Mol fraction KBr = 0.00009

Step 6: Calculate mass %

mass % KBR = (0.21 grams / (0.21 + 355) grams) *100%

mass % KBr = 0.059 %

mass % H2O = (355 grams / 355.21 grams) *100%

mass % H2O = 99.941 %

8 0

3 years ago

. an ionic compound is composed of 34.95 g of iron and 15.05 g of oxygen. find the empirical formula of this compound.

Contact [7]

Empirical formula of ionic compound is FeO. In which the composition of atoms is 1 : 1.

Empirical formula of an ionic compound is defined as the formula which gives whole number ratio of atoms of various elements present in molecule of compund.

mass of iron in compound = 34.95 g

molar mass of iron = 55.8 g

mass of oxygen in compound = 15.05 g

molar mass of oxygen = 32 g

number of moles of iron present in the compound are ratio of mass of iron in compound/ molar mass of iron

number of moles of iron in compound= 34.95 / 55.8 = 0.6263 ~ 1

number of moles oxygen in compound= 15.05/ 32 = 0.473 ~ 0.5

the ratio of the number of oxygen atoms to number of iron atoms present in one formula unit of iron compund is 2×0.5 / 1 = 1 : 1

Hence , the required empirical formula of iron compound is FeO.

To learn more about Emiprical formula, refer:

brainly.com/question/1439914

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3 0

1 year ago

Which instrument is used to take an image from outer space that shows the depletion of the ozone layer in Earth’s atmosphere?

lana [24]

Answer:

answer is satellite!

Explanation:

3 0

3 years ago

If you found carbon 13 atom, you would know that

bearhunter [10]

The Options are as follow,

a. it has 13 protons c. it has 13 neutrons

b. it has 13 electrons d. it has 7 neutrons

Answer:

Option-d is the correct answer.

Explanation:

As we know that C-13 has a atomic mass of 13. Also, atomic mass is given as,

Atomic Mass = # of Protons + # of Neutrons --- (1)

Since;

Atomic Mass = 13

And,

# of protons = 6 (as number of protons = atomic number)

Putting values in equation 1,

13 = 6 - # of Neutrons

Solving for Number of Neutrons,

# of Neutrons = 13 - 6

# of Neutrons = 7

3 0

3 years ago

Atoms of oxygen have a total of 8 electrons. Are these atoms stable, and why or why not? a.) Yes, because the Octet Rule says st

garik1379 [7]

D) otherwise we wouldn't be able to have water, oxygen gas, and all other compounds that have oxygen. We need at least 1 free slot to make a molecule

8 0

3 years ago