Unit 1: Chemical Formulas and Equations

How many different elements are involved in the following reaction? C₃H₈ + 5O₂ --> 3CO₂ + 4H₂O

• 3

• 4

• 21

• 7

How many atoms are involved in the products of the following reaction: C₃H₈ + 5O₂ --> 3CO₂ + 4H₂O

• 3

• 4

• 7

• 21

According to the Law of Conservation of Mass, what is the mass of Carbon Dioxide produced?

Methane (50.0g) + Oxygen (200g) → Carbon Dioxide (?) + Water (112.5g)

• 62.5 g

• 137.5 g

• 250 g

• 387.5 g

Which correctly identifies the reactants in this equation?

3H₂ + 3Cl₂ → 6HCl

• 3H₂

• 6HCl

• 3H₂ + 3Cl₂

• 3Cl₂

Does this equation meet the Law of Conservation of Mass?

2H₂ + O₂ --> 2H₂O

• Yes

• No

Zinc reacts with Oxygen to form Zinc Oxide. The properties of Zinc Oxide are most likely -

• similar to both Zinc and Oxygen

• similar only to Zinc

• similar only to Oxygen

• different from Zinc or Oxygen

Sodium is considered an element, while sodium bicarbonate is considered a compound. This is because sodium bicarbonate is -

• a gas at room temperature.

• given off by green plants.

• made of two different elements.

• useful to human beings.

In which of these compounds are there twice as many oxygen atoms as hydrogen atoms?

• H₃PO₄

• H₂SO₄

• HClO₃

• H₂O

Which of these formulas contain equal numbers of nitrogen atoms?

• Formulas I and II

• Formulas I and III

• Formulas II and IV

• Formulas I and IV

What is the correct way to write the formula for the model of this compound?

• 2H₂0

• 2H₂O

• 2HO₂

• H₂O₂