Formulas and Elements

The chemical formula for sodium sulfate is Na₂SO₄. How many sulfur atoms are in the formula for sodium sulfate?

• 1

• 2

• 4

• 8

Answer explanation

The chemical formula for sodium sulfate contains 1 sulfur atom, as indicated by the subscript in the formula Na2SO4.

Tags

8.5D

Which of the models best represents CaCO₃?

• 
• 
• 
• 

Tags

8.5D

How many elements are in C₆H₁₂O₆?

• 1

• 2

• 3

• 4

Answer explanation

C6H12O6 consists of 3 elements: Carbon (C), Hydrogen (H), and Oxygen (O), making the correct answer 3.

Tags

8.5D

A student is studying calcium, a highly reactive element that humans need for strong bones. Which characteristic of calcium is most linked to its reactivity?

• The 20 protons in each atom of calcium

• The density of calcium

• The atomic number

• The two valence electrons in each atom of calcium

Answer explanation

The two valence electrons in each atom of calcium are most linked to its reactivity.

Tags

8.5B

When balancing an equation, how many Hydrogen would you say are present in 4H₂O?

• 6

• 8

• 2

• 4

Answer explanation

To balance the equation, you need to consider each element. In 4H2O, there are 4 molecules of water, each with 2 Hydrogen atoms. So, the total number of Hydrogen atoms is 4*2=8.

Tags

8.5D

Sodium sulfate is used in laundry detergent. It is a compound that contains 2 atoms of sodium, 1 atom of sulfur, and 4 atoms of oxygen. What is the correct chemical formula for sodium sulfate?

• NA₂SO₄

• Na₂S₂O₄

• Na₂SO₄

• Na₂SO₈

Answer explanation

The correct chemical formula for sodium sulfate is Na₂SO₄ because it contains 2 atoms of sodium, 1 atom of sulfur, and 4 atoms of oxygen.

Tags

8.5D

What combination of beads should the use to model the formula C₆H₁₂O₆? Blue represents carbon, green represent oxygen and red represent hydrogen.

• 6 blue, 6 red and 6 green

• 12 green, 6 red and 6 blue

• 12 red, 6 blue and 6 green

• 12 blue, 6 green and 6 red

Answer explanation

Choose 12 red beads for hydrogen, 6 blue beads for carbon, and 6 green beads for oxygen to model C6H12O6.

Tags

8.5D

A group of students are generating a statement that accurately describes the chemical formula displayed below.

C₃H₇NO₂

What information would accurately complete the statement? Move ONE correct answer to each box.​

There are (a)   elements and​​ (b)   total atoms involved in the chemical formula displayed.

• 4

• 13

• 1

• 2

• 3

• 9

• 12

• 14

Answer explanation

The correct answers are 4 elements and 13 total atoms involved in the chemical formula displayed, which accurately describes C3H7NO2.

Tags

8.5D

What term is used to describe the number highlighted, when referring to the number of molecules react?

• An Atom

• The Subscript

• A Molecule

• The Coefficient

Answer explanation

The term used to describe the number highlighted, when referring to the number of molecules react, is The Coefficient.

Tags

8.5D

The above diagram is a model of a molecule of methane.  What is the formula for methane? 

• CH₈

• C₈H₄

• CH₄

• C₈H₈

Answer explanation

The correct formula for methane is CH4, as shown in the diagram. Therefore, the correct choice is CH₄.

Tags

8.5D