Which of these is a pure substance?

a. diamond

b. salt

c. ocean water

a

a and b

b and c

all of them

Carbon-14 is a naturally-occuring, stable isotope that is commonly used is scientific studies as a tracer and to date artifacts. Using the periodic table, predict the number of electrons, neutrons, and protons in carbon-14.

The atoms in a sample of carbon must contain nuclei with the same number of

Which of the following statements are true about gravity? Check all that apply. A. Gravity doesn't exist between Earth and the sun. B. Gravity exists only on Earth. C. Gravity exists in the whole universe. D.

Which of the following simple machines is not properly identified? A. Scissors: lever B. Pizza cutter: wedge C. Screw: wheel and axle D. Ramp: inclined plane

Which of the following describes an electric fan?

Through which medium would EM waves travel the fastest? A. The Ocean B. The Atmosphere C. Rocks

Average mass of a toy car (small, hot wheels) ?

A cannon directed straight upward launches a ball with an initial speed v. The ball reaches a maximum height h in a time t. Then, the same cannon is used to launch a second ball straight upward at a speed 2v.

Does the sun fuse hydrogen into helium or vice versa?

Is it possible to put a distance versus time graph to be universal go mine