CHEM 101 EXAM 1 PRACTICE QUESTIONS
WITH CORRECT ANSWERS
What is the chemical formula for Iron Oxide? What roman numeral needs to go with it? -
CORRECT ANSWER -Fe2O3
Iron (III) Oxide
What is the name of a compound with the chemical formula N2O5? - CORRECT ANSWER -
Dinitrogen pentoxide.
Calculate the new volume when the pressure on 5.0L of gas at 1.8 atm is increased to 4.5 atm. -
CORRECT ANSWER -P1V1=P2V2
(1.8)(5)=(4.5)(x)
x=2
New volume is 2 L.
90% of the universe today is made up of two elements. What are they? - CORRECT ANSWER -
The first two elements on the periodic table.
Hydrogen (H) and Helium (He).
Name the halogens. - CORRECT ANSWER -
Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), Astatine (At)
Funny Clowns Broil Innocent Ants.
Convert 8.3 x10^7 inches to meters.
1 meter = 39.4 inches - CORRECT ANSWER -In calculator: (8.3x10^7)/39.4
Ans: 2,106,598.98
, Correct Sig figs: 2,100,000 OR 2.1x10^6
Reminder: always be extra careful using scientific notation in your calculator. I'd suggest always
using parentheses.
Which of the following is a homogeneous mixture?
Salt water
Pure sulfur
Bubble tea - CORRECT ANSWER -salt water
a homogenous mixture you can think of a "blended" mixture or a dissolved solution.
A heterogenous mixture is more like ice cubes in water, or boba and milk tea.
What is the chemical formula of Aluminum sulfide? - CORRECT ANSWER -Al2S3
What is the charge of a barium ion? Ba - CORRECT ANSWER -Ba^2+
How many protons, neutrons, and electrons are in a calcium atom?
How many in a calcium ion? - CORRECT ANSWER -
The atomic number is 20. Calcium has 20 protons.
The mass is 40.08, which accounts for the number of protons + neutrons. # protons -
atomic mass = # neutrons
40.08 - 20 = 20 neutrons.
20 electrons. Electrons should always be the same amount as the protons (so the atomicBnumbe
r). UNLESS it's a charged ion.
Ca ion has a 2+ charge meaning it has TWO LESS electrons, making it more positive.
In this case, the number of protons and neutrons don't change, but the number of electrons dec
reases by two, leaving 18 electrons for the Ca++ ion.
WITH CORRECT ANSWERS
What is the chemical formula for Iron Oxide? What roman numeral needs to go with it? -
CORRECT ANSWER -Fe2O3
Iron (III) Oxide
What is the name of a compound with the chemical formula N2O5? - CORRECT ANSWER -
Dinitrogen pentoxide.
Calculate the new volume when the pressure on 5.0L of gas at 1.8 atm is increased to 4.5 atm. -
CORRECT ANSWER -P1V1=P2V2
(1.8)(5)=(4.5)(x)
x=2
New volume is 2 L.
90% of the universe today is made up of two elements. What are they? - CORRECT ANSWER -
The first two elements on the periodic table.
Hydrogen (H) and Helium (He).
Name the halogens. - CORRECT ANSWER -
Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), Astatine (At)
Funny Clowns Broil Innocent Ants.
Convert 8.3 x10^7 inches to meters.
1 meter = 39.4 inches - CORRECT ANSWER -In calculator: (8.3x10^7)/39.4
Ans: 2,106,598.98
, Correct Sig figs: 2,100,000 OR 2.1x10^6
Reminder: always be extra careful using scientific notation in your calculator. I'd suggest always
using parentheses.
Which of the following is a homogeneous mixture?
Salt water
Pure sulfur
Bubble tea - CORRECT ANSWER -salt water
a homogenous mixture you can think of a "blended" mixture or a dissolved solution.
A heterogenous mixture is more like ice cubes in water, or boba and milk tea.
What is the chemical formula of Aluminum sulfide? - CORRECT ANSWER -Al2S3
What is the charge of a barium ion? Ba - CORRECT ANSWER -Ba^2+
How many protons, neutrons, and electrons are in a calcium atom?
How many in a calcium ion? - CORRECT ANSWER -
The atomic number is 20. Calcium has 20 protons.
The mass is 40.08, which accounts for the number of protons + neutrons. # protons -
atomic mass = # neutrons
40.08 - 20 = 20 neutrons.
20 electrons. Electrons should always be the same amount as the protons (so the atomicBnumbe
r). UNLESS it's a charged ion.
Ca ion has a 2+ charge meaning it has TWO LESS electrons, making it more positive.
In this case, the number of protons and neutrons don't change, but the number of electrons dec
reases by two, leaving 18 electrons for the Ca++ ion.
