Question 1

Which of the following formulas is used to calculate the percentage composition of an element in a compound?

Accepted Answer

Mass of element ÷ Molar mass of compound × 100

Answer

Molar mass of compound ÷ Mass of element × 100

Answer

Atomic number ÷ Atomic mass × 100

Answer

Mass of compound ÷ Mass of element × 100

Question 2

What is the first step in finding the percentage composition of a compound?

Accepted Answer

Identify the elements present in the compound.

Answer

Divide the atomic mass by the number of atoms.

Answer

Multiply all atomic numbers together.

Answer

Subtract atomic masses from the molar mass.

Question 3

What does the term molar mass mean?

Accepted Answer

The total mass of one mole of a substance.

Answer

The ratio of elements in a compound.

Answer

The number of atoms in a compound.

Answer

The mass of one atom of an element.

Question 4

What is the molar mass of H₂O?

Accepted Answer

18 g/mol

Answer

16 g/mol

Answer

20 g/mol

Answer

17 g/mol

Question 5

Using your answer from #4, what is the percentage of oxygen in water (H₂O)?

Accepted Answer

88.9%

Answer

22.2%

Answer

11.1%

Answer

44.4%

Question 6

The molar mass of carbon dioxide (CO₂) is 44 g/mol. What is the percentage of carbon in CO₂?

Accepted Answer

27.3%

Answer

27%

Answer

32%

Answer

12%

Question 7

If one molecule of glucose (C₆H₁₂O₆) has a molar mass of 180 g/mol, what is the percentage of carbon?

Accepted Answer

40%

Answer

50%

Answer

20%

Answer

33.3%

Question 8

Why is calculating the percentage composition of a compound important in food science?

Accepted Answer

To identify the nutrients and their proportions in food.

Answer

To know the color and texture of food.

Answer

To measure how much water is in a container.

Answer

To find the brand of food.

Question 9

Knowing the percentage of elements in food helps people _______.

Accepted Answer

Choose a balanced and healthy diet.

Answer

Prepare food faster.

Answer

Increase food prices.

Answer

Avoid eating carbohydrates.

Question 10

A farmer uses the percentage composition of compounds to ____________________.

Accepted Answer

Determine which fertilizer contains more essential nutrients for plants.

Answer

Change the taste of harvested crops.

Answer

Count the number of seeds in the field.

Answer

Measure the color of the soil.

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