Question

circle the number which best answers each question.
1 the particle diagram below represents a sample of matter.
which best describes the composition of the sample?
(1) single element
(2) a mixture of elements
(3) a mixture of compounds
(4) a single compound
2 the particle diagram below represents a mixture of reactants.
which diagram for the products of the reaction demonstrates the law of conservation of mass?
3 the particle diagram below represents a sample of matter.
which best describes the composition of the sample?
(1) single element
(2) a mixture of elements
(3) a mixture of compounds
(4) a single compound
4 the particle diagram below represents a sample of matter.
which best describes the composition of the sample?
(1) a heterogeneous mixture of elements and compounds
(2) a heterogeneous mixture of elements
(3) a homogeneous mixture of elements
(4) a homogeneous mixture of elements and compounds
for each of the following, determine if it is a chemical or physical change and justify your answer.
physical or chemical:
justify:
physical or chemical:
justify:
the first image below shows hi in liquid form. in the second box, draw hi after it changes to the gaseous state.

Explanation:

Step1: Analyze question 1

The particle - diagram in question 1 shows identical molecules made of two different types of atoms. This indicates a single compound.

Step2: Analyze question 2

The Law of Conservation of Mass states that the number and type of atoms before and after a reaction must be the same. In the reactant diagram, there are single - atom elements and di - atomic elements. The product diagram that has the same number and type of atoms as the reactant diagram is the one that demonstrates the Law of Conservation of Mass.

Step3: Analyze question 3

The particle diagram in question 3 shows different types of single - atom elements mixed together, which is a mixture of elements.

Step4: Analyze question 4

The particle diagram in question 4 shows a non - uniform distribution of different elements and compounds, which is a heterogeneous mixture of elements and compounds.

Step5: Analyze physical/chemical change questions

For the first physical/chemical change question, new substances are formed as the molecules are rearranged, so it is a chemical change. For the second physical/chemical change question, the molecules just change their arrangement and no new substances are formed, so it is a physical change.

Step6: Draw HI in gaseous state

In the gaseous state, HI molecules are more spread out compared to the liquid state.

Answer:

1. (4) a single compound
2. (4) (the diagram with the same number and type of atoms as the reactant diagram)
3. (2) a mixture of elements
4. (1) a heterogeneous mixture of elements and compounds

Physical or Chemical (first pair): Chemical; Justify: New substances are formed.
Physical or Chemical (second pair): Physical; Justify: No new substances are formed, only change in arrangement.
For drawing HI in gaseous state: Draw HI molecules more spread out than in the liquid - state diagram.