Aria and Marcus attend a science LiveLesson. During the LiveLesson, the teacher explains that glucose is broken down in the body when it reacts with oxygen gas to form carbon dioxide and water. The teacher explains that the process actually occurs in several steps, but she shows them the following overall reaction and encourages them to think about the law of conservation of matter.

Question

Aria and Marcus attend a science LiveLesson.  During the LiveLesson, the teacher explains that glucose is broken down in the body when it reacts with oxygen gas to form carbon dioxide and water.  The teacher explains that the process actually occurs in several steps, but she shows them the following overall reaction and encourages them to think about the law of conservation of matter.

C6
H12
O6
 + 6O2
 → 6CO2
 + some amount of H2
O

a. There are 12 atoms of hydrogen shown on the reactant side. How many total atoms of hydrogen must be on the product side?

(1 point)
Responses

2
2

6
6

12
12

18
18
Question 2
b.  What does the law of conservation of matter (or the law of conservation of mass) tell the students?(1 point)
Responses

Matter might be lost in a chemical or physical process.
Matter might be lost in a chemical or physical process.

Matter is never gained or lost in a chemical or physical process.
Matter is never gained or lost in a chemical or physical process.

Matter might be gained in a chemical or physical process.
Matter might be gained in a chemical or physical process.

Matter is always gained or lost in a chemical or physical process.
Matter is always gained or lost in a chemical or physical process.
The teacher explains that burning sugar in a test tube doesn't produce the same results as breaking down sugar in the body, because some of the sugar is charred to form a dark brown or black residue, but she stresses that the law of conservation of matter is still followed.  She shows them this video of the burning of sugar in a test tube.  (If you have technical trouble and can't get the video to play, don't worry; you can still answer the question even if you can't watch the video.)

Video Player

Question 3
c.  If the video shows the burning of 1.80 grams of sugar with 1.92 grams of oxygen gas, what would Aria and Marcus expect the total mass of all the products (including the gases) to be?  Why?

You can use the calculator (below the answers) if desired.

(1 point)
Responses

The total mass of the products would equal 1.80 grams, because the mass of oxygen gas doesn't make a difference.
The total mass of the products would equal 1.80 grams, because the mass of oxygen gas doesn't make a difference.

The total mass of the products would be greater than 3.72 grams, because water is really heavy.
The total mass of the products would be greater than 3.72 grams, because water is really heavy.

The total mass of the products would be something less than 3.72 grams, because some of the mass burned into nothing.
The total mass of the products would be something less than 3.72 grams, because some of the mass burned into nothing.

The total mass of the products would be 3.72 grams, because mass cannot be gained or lost in the process.

GPT-4o mini · Answer

Let's go through each question step by step:

Question 1 (a): There are 12 atoms of hydrogen shown on the reactant side. How many total atoms of hydrogen must be on the product side?

In a chemical reaction, according to the law of conservation of matter, the number of atoms of each element must be the same on both sides of the equation. Since there are 12 hydrogen atoms in the reactants (in glucose, C6H12O6), there must also be 12 hydrogen atoms on the product side.

Response: 12

Question 2 (b): What does the law of conservation of matter (or the law of conservation of mass) tell the students?

The law of conservation of matter states that matter is neither created nor destroyed in a chemical or physical process. Therefore, the total mass of the reactants must equal the total mass of the products.

Response: Matter is never gained or lost in a chemical or physical process.

Question 3 (c): If the video shows the burning of 1.80 grams of sugar with 1.92 grams of oxygen gas, what would Aria and Marcus expect the total mass of all the products (including the gases) to be? Why?

According to the law of conservation of mass, the total mass of the products must equal the total mass of the reactants. So, we add the mass of the sugar and the mass of oxygen.

Total mass of reactants = mass of sugar + mass of oxygen = 1.80 grams + 1.92 grams = 3.72 grams

Therefore, the total mass of the products would be 3.72 grams, as mass is conserved in the chemical reaction.

Response: The total mass of the products would be 3.72 grams, because mass cannot be gained or lost in the process.