Atoms
Which of these statements is false?
a. Electrons have a negative charge.
b. Electrons have a mass of 1 amu.
c. The nucleus of an atom is positively charged.
d. Neutrons are found in the nucleus of an atom.
b. Electrons have a mass of 1 amu.
Name the elements that form the compound NaSO4.
a. nitrogen, sulfur, oxygen
b. sodium, sulfur, oxygen
c. neon, silver, oxygen
d. sodium, silver, oxygen
b. sodium, sulfur, oxygen
The sign of a chemical change is ______
formation of new substance
Which of the following is a pure substance?
a. tea
b. brass
c. ocean water
d. carbon dioxide
d. carbon dioxide
Which of the following statements about the atoms and molecules in all three states of matter is NOT true?
a. Particles of matter are in constant motion.
b. Space exists between the particles.
c. Adding heat increases the size of the particles.
d. The particles of matter are too small to be seen with the unaided eye.
c. Adding heat increases the size of the particles.
What is the total number of subatomic particles (protons, electrons, and neutrons) in an atom of vanadium-51?
a. 51
b. 74
c. 102
d. 125
b. 74
Which property would be MOST useful for determining whether a piece of metal is iron or lead?
a. ability to conduct electric current
b. solubility in water
c. size of the piece of metal
d. attraction to a magnet
d. attraction to a magnet
A lab student places some sodium hydroxide solution into a test tube and adds a drop of phenolphthalein solution to it. Both sodium hydroxide and phenolphthalein are colorless, yet when mixed together, the solution turns pink. What has occurred?
a. heterogeneous mixture
b. a chemical change
c. the formation of a solid
d. a physical change
b. a chemical change
Which method would be MOST useful in separating two substances with very different boiling points?
a. burning
b. distillation
c. electricity
d. filtration
b. distillation
Gases are easier to compress than liquids because particles in gases are
a. less brittle.
b. free to flow from one location to another.
c. farther apart.
d. smaller.
c. farther apart.
The number 80 in the name bromine-80 represents:
a. the atomic number.
b. the mass number.
c. the sum of protons and electrons.
d. none of these.
b. the mass number.
Which list contains only elements?
a. Au, I, KO, Pb
b. Pb, Hg, Cd, Rb
c. SO2, NO2, CO2, LiH
d. Pt, SiC, Cs, Zn
b. Pb, Hg, Cd, Rb
In any physical or chemical change, mass is _______.
Conserved
Distillation can be used to separate substances in
a. compounds.
b. elements.
c. heterogeneous mixtures.
d. solutions.
d. solutions.
During _______, a liquid produces a vapor that is then condensed again to a liquid.
Boiling
Which of the following is NOT a part of Dalton’s atomic theory?
a. All elements are composed of atoms.
b. Atoms of the same element are alike.
c. Atoms are always in motion.
d. Atoms that combine do so in simple whole-number ratios.
c. Atoms are always in motion.
A compound can be physically separated into its elements.
True or False
False
A _______ property is a quality of a substance that can be observed or measured without changing the composition of the substance.
Physical
Elements combine chemically to form _______.
Compounds
A basketball has more mass than a golf ball because:
a. the basketball takes up more space.
b. the basketball contains more matter.
c. the golf ball contains a different kind of matter.
d. the golf ball has an indefinite composition.
b. the basketball contains more matter.