8.6DE - Test 4.2 Review

A 20.0 g sample of magnesium reacts with oxygen to form 26.6 g of magnesium oxide. How many grams of oxygen reacted?

• 6.6 grams

• 5.6 grams

• 7.6 grams

• 8.6 grams

A student creates a mixture of water and washing soda weighing 10 g and a mixture of water and epsom salts weighing 15 grams. According to the law of conservation of mass, what should the weight of the products be after he mixes them?

• 25 grams

• 20 grams

• 30 grams

• 35 grams

Why does a chemical reaction follow the law of conservation of mass? Select TWO correct answers.

• Only new reactants can form, but new products cannot.

• Both reactants and products must have the same elements present.

• Both reactants and products must have different elements present.

• No new elements can be created or destroyed in a chemical reaction.

• The total mass of the products is always less than the total mass of the reactants.

Which pH level correlates with a slippery texture?

• Above 7

• Below 7

• Exactly 7

• Neutral

What is the pH level of ammonia?

• 7.3

• 4.0

• 11.0

• 6.5

Which substance is acidic?

• Blood

• Orange Juice

• Ammonia

• Milk

What is the characteristic of blood in terms of acidity or basicity?

• Acidic

• Slightly Basic

• Basic

• Slightly Acidic

According to the Law of Conservation of Mass, is the chemical equation CH₄ + 2O₂ → 2CO₂ + 2H₂O balanced or unbalanced?

• Balanced

• Unbalanced

• Cannot be determined

• Partially balanced

How many carbon atoms are present in the products of the equation CH₄ + 2O₂ → 2CO₂ + 2H₂O?

• 1

• 2

• 3

• 4

What is the minimum rubric score a student can receive for their response to the question about the chemical equation?

• 0

• 1

• 2

• 3