Sodium reacts with chlorine to form the compound sodium chloride, or salt. The chemical formula below shows how the two elements combine into a compound.

Question

2Na + Cl2 → 2NaCl

If the total mass of the reactants is 58.44 amu, what will be the total mass of the products?

(1 point)
Responses

Answer 1

In a chemical reaction, the law of conservation of mass states that the total mass of the reactants must equal the total mass of the products. Therefore, if the total mass of the reactants is 58.44 amu, the total mass of the products will also be 58.44 amu.

So, the total mass of the products will be 58.44 amu.

Answer 2

Which procedure could be used to demonstrate that matter is conserved during a physical change?(1 point)
Responses

Find the mass of an apple. Cut the apple and remove the core. Find the mass of the remaining apple.
Find the mass of an apple. Cut the apple and remove the core. Find the mass of the remaining apple.

Find the mass of a piece of ice. Let the ice melt. Find the mass of the liquid water.
Find the mass of a piece of ice. Let the ice melt. Find the mass of the liquid water.

Find the mass of a raw egg. Cook the egg. Find the mass of the cooked egg.
Find the mass of a raw egg. Cook the egg. Find the mass of the cooked egg.

Find the mass of a cup of water. Boil the water. Find the mass of the water that remains.
Find the mass of a cup of water. Boil the water. Find the mass of the water that remains.

Answer 3

To demonstrate that matter is conserved during a physical change, you should choose a procedure that involves a change of state without any mass being lost or gained during the process.

The best option from the provided responses is:

Find the mass of a piece of ice. Let the ice melt. Find the mass of the liquid water.

In this case, you are observing a physical change (melting) where the state of the matter changes from solid to liquid, but the total mass before and after the change should remain the same, illustrating the conservation of mass.

Answer 4

The image is a model of sulfuric acid that has a chemical formula of H2SO4. In 1-2 sentences, explain why creating models, like the one shown in the image above, is important in understanding substances.

(2 points)

Answer 5

Creating models, like that of sulfuric acid (H₂SO₄), is important because they visually represent the arrangement of atoms and the bonding between them, helping to illustrate the structure and properties of the substance. These models enhance comprehension by allowing students to visualize complex molecules, making it easier to grasp concepts such as molecular geometry, polarity, and reactivity.

Answer 6

Use the chemical equation to complete the activity.

2Cu+S→Cu2S
2
Cu
+
S
→
Cu
2
S
Copper (Cu) reacts with sulfur (S) to form copper sulfide as shown in the equation. A scientist adds 12.7 grams of Cu to 3.2 grams of S to start the reaction. In this reaction, all of the copper and all of the sulfur react. Before running the experiment, the scientist expected the products of the reaction will be a total of 15.9 grams of copper sulfide (Cu2S). In 1–2 sentences, explain the law that the scientist used to predict that the product of the reaction would be 15.9 grams of copper sulfide.

(2 points)

Answer 7

The scientist used the law of conservation of mass, which states that in a closed system, the total mass of the reactants is equal to the total mass of the products. By adding the masses of copper (12.7 grams) and sulfur (3.2 grams), which totals 15.9 grams, the scientist predicted that this would be the mass of the copper sulfide (Cu₂S) produced in the reaction.

Answer 8

Why are sodium (Na) and potassium (K) in the same group on the periodic table?(1 point)
Responses

They are both colorless.
They are both colorless.

They have similar reactivity.
They have similar reactivity.

They have similar atomic weights.
They have similar atomic weights.

They are both hard and brittle.

Answer 9

Sodium (Na) and potassium (K) are in the same group on the periodic table because they have similar reactivity. Elements in the same group often exhibit similar chemical properties due to having the same number of valence electrons.