Semester Exam 7th Grade Science

If you do not understand a direction or part of a laboratory procedure, you should

• figure it out as you do the lab

• try several methods until something works

• ask the teacher before proceeding

• skip it and go on to the next part

The following activity is permitted in the laboratory:

• chewing gum

• eating

• drinking

• None of the above.

Before you leave the science room, you should

• clean your work area and equipment.

• return all equipment to the proper storage area.

• wash your hands with soap and water.

• All of the above.

You have been injured in the laboratory (cut, burned, etc.). First you should

• visit the school nurse after class

• see a doctor after school

• tell the teacher at once

• apply first aid yourself

Horseplay, practical jokes, or pranks in the classroom are

• always against the rules

• okay

• not dangerous

• okay if you are working alone

This table shows the number of atoms of each element present in a molecule of citric acid, a sour-tasting compound found in citrus fruits.

• CHO

• C₆H₈O₇

• C₆H₁₀O₇

• C₆(H₂O)₃

Tags

NGSS.MS-PS1-1

There are two types of changes that substances can undergo: physical changes and chemical changes. Which of these is always evidence that a change is a chemical change?

• production of bubbles

• change in volume

• formation of a new substance

• increase in temperature

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Changes to substances can be chemical changes or physical changes. Which of the following examples demonstrates a chemical change?

• milk becoming sour when it stands on a kitchen counter

• water boiling to form steam

• crystals forming in saltwater as water evaporates

• sugar dissolving in a cup of hot tea when it is stirred

Tags

NGSS.MS-PS1-2

The diagram shows one molecule of caffeine. A caffeine molecule has 8 atoms of Carbon, 10 atoms of Hydrogen, 4 atoms of Nitrogen, and 2 atoms of Oxygen. What are the elements found in this compound in alphabetical order.

Tags

NGSS.MS-PS1-1

During a lab investigation, students measured the distance a toy car moved along a track. During one trial, the toy car moved 13 m in 5 s. Calculate the average speed of the toy car in meters per second.