1 Matter always has both mass and volume.
2 Which is a scientific observation?
Freezing and boiling are called physical changes
Water freezes at zero degrees C
If a substance has a density of 1.00g/mL it must be water.
When a substance freezes its molecules lose potential energy.
3 Which phase of matter can be compressed or expanded to the greatest degree?
“When Jill opened the bottle containing a clear liquid, the whole room smelled like roses.” Based on this statement we can infer that:
The liquid is a homogeneous mixture.
The liquid is a compound.
Inside the bottle there were a liquid and a gas.
Opening the bottle caused the liquid to evaporate.
The following alternatives represent numbers that were expressed to three significant figures. Which of the alternatives is expressed incorrectly?
45.7899 to 45.8
890.332 to 891
0.002346 to 0.00235
1543456 to 1.54 x 106
6 The weight of a substance depends on gravity.
7 A solid with a specific gravity of 0.800 will float in water.
8 One centigram is equal to
9 If two substances have the same mass, the one with the greater volume will have the greater density.
10 The smallest particle of an element that can enter into a chemical reaction is a(n)
11 Which element forms diatomic molecules?
12 Which is an anion?
13 Which is a physical change?
Decomposition of water by electrolysis
Salt dissolving in water
Converting alcohol to vinegar
14 Which pair of formulas illustrates the Law of Multiple Proportions?
CH3Cl and CH3OH
H2O and HOH
CuCl2 and CuBr
H2O and H2O2
15 What is the relative mass of a proton?
16 Different isotopes of an element are atoms of that element which have
the same atomic number and the same mass number.
the same atomic number and different mass number.
different atomic number and the same mass number.
different atomic number and different mass number.
17 Every atom is electrically neutral.
18 How many atoms of oxygen are indicated in the formula Fe(NO3)2?
19 One unit of aluminum sulfide contains two atoms of aluminum for every three atoms of sulfur. What is the chemical formula for aluminum sulfide?
20 What is the mass number of an atom that contains 23 protons, 23 electrons, and 28 neutrons?
21 Let Z represent atomic number, A represent mass number, and N represent the number of neutrons in an atom. Which of the following is correct?
N = A + Z
Z = A + N
N = A – Z
A = N – Z
22 What is the name of the element with an atomic number of 80?
23 Consider the chemical formula for one molecule of methane, CH4. If instead of one molecule we had 10 molecules of methane, how many carbon atoms would be present?
24 Carbon, when burned completely, forms carbon dioxide. If 11.7g of carbon combines with 31.3g of oxygen, what mass of carbon dioxide will be produced?
25 To heat 60.0g of water from 30.0ºC to 50.0ºC requires