Sc 8 P 8 2

Which of these is not an example of a pure substance?

• aluminum can

• milk

• table salt

• water

Shelby filled three empty soda bottles with 5 g of steel wool, a material used for cleaning that also rusts quickly. She added 100 mL of water to each bottle and then resealed the bottle. She placed each bottle in one of three different locations: in a refrigerator at 3 °C, in a room at 25 °C, and in a warm kitchen at 30 °C. She observed the bottles every day for a week and recorded the amount of rust that formed on the steel wool. Which research question does this experiment best investigate?

• Does a gas form when steel wool rusts?

• Does the temperature in a room vary widely over time?

• Does the amount of water effect how quickly steel wool rusts?

• Does temperature affect the amount of rust that forms on steel wool?

An atom's atomic number of an element is the number of protons in the nucleus of one of its atoms.

• True

• False

The nucleus of an atom is its tiny central region, and comprises the bulk of the atom's mass, containing the protons and neutrons.

• True

• False

Tags

NGSS.MS-PS1-1

Elian is testing his hypothesis that the more ripe an orange is, the more Vitamin C it contains. He takes four oranges of varying degrees of ripeness and squeezes samples of juice from each one. He then measures the concentration of Vitamin C in each sample of orange juice. He systematically adds a measured amount of a chemical called a titrant into the orange juice, waiting for its color to change. When its color changes, he knows that the amount of Vitamin C present in the juice is equal to the amount of the titrant he has added, which he can calculate. What does Elian think is the independent variable in this experiment?

• orange ripeness

• amount of titrant

• color of the solution

• amount of Vitamin C per orange

Tags

NGSS.MS-ETS1-1

Students are conducting an experiment assessing how color affects the amount of solar energy that is absorbed. Students will make construction paper pockets out of 3 different colors of construction paper.What is the independent variable in this experiment?

• the light used

• the thermometer used

• the color of the paper

The __________ and _________ make up the majority of an atoms atomic mass.

• protons and electrons

• electrons and neutrons

• protons and neutrons

An atom's atomic weight measures the total of the mass of the protons, neutrons, and electrons.

• True

• False

Protons are small, positively-charged atomic particles

• True

• False

Kyle wanted to see which gum had the most sugar. He chose four different brands of gum. He weighed each piece. Then he chewed each piece for 10 minutes. After that, he let the gum dry and weighed it again. He recorded his data in the table below. What is the independent variable in Kyle's experiment?

• the weight of the final dried gum

• the time chewed

• the change in weight of the gum

• the brand of gum