Question

1. lab partners follow the instructions during their chemistry investigation very carefully. they measure 200 ml of a clear liquid into a beaker. then they measure 50 ml of a different clear liquid into a graduated cylinder. they pour the liquid from the graduated cylinder into the beaker. the image above shows the results.

which should the partners conclude about the two liquids?
a. both liquids cooled when they were mixed.
b. filtering would make it possible to separate the liquids.
c. a chemical reaction occurred when the liquids were mixed.
d. a new substance with the same properties as the original liquids formed.

1. the first part of a balanced chemical equation is shown: ( cu + 2agno_3 \to )____, in order for the equation to be balanced, how many oxygen (o) atoms must be present in the products?

a. 2
b. 3
c. 5
d. 6

1. which of the following represents a molecule?

a. ca
b. co
c. co
d. cu

Explanation:

Question 3

• Option A: There is no indication of temperature change (cooling) in the image or description.
• Option B: Filtration is for separating solids from liquids, not two miscible/immiscible liquids (no solid - liquid separation context here).
• Option C: A chemical reaction likely occurred as there is a visible change (maybe a precipitate or new substance formation, indicated by the “results” image which shows a non - homogeneous mixture in a way that suggests a reaction).
• Option D: If a new substance formed, its properties would be different from the original liquids.

• In the reactant \(2AgNO_3\), each \(AgNO_3\) has 3 oxygen atoms.
• So for \(2AgNO_3\), the number of oxygen atoms is \(2\times3 = 6\). According to the law of conservation of mass (atoms are conserved in a chemical reaction), the number of oxygen atoms in the products must be equal to the number of oxygen atoms in the reactants.

• Option A: \(Ca\) is an atom (calcium element).
• Option B: \(Co\) is an atom (cobalt element).
• Option C: \(CO\) is a molecule (carbon monoxide, formed by the combination of a carbon atom and an oxygen atom).
• Option D: \(Cu\) is an atom (copper element).

Answer:

C. A chemical reaction occurred when the liquids were mixed.

Question 4