Question

1. which of the following is not a pure substance?

a. helium
b. carbon dioxide
c. seawater
d. glucose

1. peter places six balls of modeling clay on one side of a balance. he places a plastic cup on the other side.

it takes 41 plastic cubes to balance the modeling clay. he then removes the clay, shapes it into a dinosaur, and puts it back on the balance. how many cubes will he most likely need to put into the cup to balance the dinosaur?
a. 35
b. 38
c. 41
d. 47

1. the following illustration shows a tool that can be used to separate elements of certain mixtures. this tool can separate what type of mixture?

Explanation:

22.

A pure substance has a definite and constant composition. Helium is an element, carbon dioxide and glucose are compounds. Seawater is a mixture of water, salts, and other substances.

Step1: Understand mass property

The mass of the modeling - clay remains the same regardless of its shape.

Step2: Recall balance condition

Since it took 41 plastic cubes to balance the six balls of modeling clay initially, it will take the same number of cubes to balance the clay in dinosaur - shape.

Answer:

c. Seawater

23.