Final Exam Review CHM 2045 questions with
answers
element - **🔰 VERIFIED ANSWERS🔰 ✔✔simplest form of matter; cannot be broken
down by chemical means. An atom is the smallest unit of an element.
A substance that cannot be broken down into simpler substances
compound - **🔰 VERIFIED ANSWERS🔰 ✔✔made up of two or more elements
chemically combined in fixed proportions. A molecule is the smallest unit of a compound.
mixture - **🔰 VERIFIED ANSWERS🔰 ✔✔made of substances (elements and/or
compounds) mixed together in no fixed composition. A homogeneous mixture will appear
uniform throughout is sometimes called a solution. A heterogeneous mixture varies in its
composition (you will see distinct parts or phases).
Density - **🔰 VERIFIED ANSWERS🔰 ✔✔For irregularly-shaped solids:
1- take mass of solid (or given)
2- determine the volume of solid by displacement of water
Example: A solid weighing 25.22 grams is dropped into a graduated cylinder containing 15.6
mL of water. The water level rises to 25.0 mL. Calculate the density of the solid.
D = Mass = 25.22 g = 25.22 g = 2.7 g/mL
Volume (25.0 - 15.6)mL 9.4 mL
For liquids:
, 1- take the mass of the empty graduated cylinder
2- add volume of liquid (record the volume)
3- determine the mass of the liquid by added mass to container.
naming compounds, giving formulas------Naming Ionic Compounds - **🔰 VERIFIED
ANSWERS🔰 ✔✔For binary ionic compounds (meaning one metal with one nonmetal), we
name the metal and name the nonmetal with an -ide ending.
For these metals, we do not have to specify their charge when naming the compound.
specify their charge in the name. In these cases where the metal can have more than one
charge, name the metal, identify the charge of the metal using roman numerals in
parenthesis, and name the nonmetal with an -ide ending.
protons, neutrons and electrons - **🔰 VERIFIED ANSWERS🔰 ✔✔protons = atomic
number
Neutrons = mass number - atomic number
Electrons = protons (for any atom, which is neutral)
Temperature Conversions - **🔰 VERIFIED ANSWERS🔰 ✔✔°F = 1.8 (°C) + 32 or (°F -
32) = °C
1.8
and °C + 273.15 = K
Percent Composition - **🔰 VERIFIED ANSWERS🔰 ✔✔Mass Percent
Mass percent refers to the percent by mass of each element in the compound. Make sure to
add up the mass of each atom of element to get the total mass of each element first. (for
example, Na2SO4 would have 2 Na atoms, 1 sulfur and 4 oxygen atoms). Add the total mass
of all elements together to get the molar mass. Divide the total mass of each element by the
molar mass, multiply by 100, and there's your % mass for that element. Percent composition
should provide the mass percent of every element in the compound and thus, should total
100%.
answers
element - **🔰 VERIFIED ANSWERS🔰 ✔✔simplest form of matter; cannot be broken
down by chemical means. An atom is the smallest unit of an element.
A substance that cannot be broken down into simpler substances
compound - **🔰 VERIFIED ANSWERS🔰 ✔✔made up of two or more elements
chemically combined in fixed proportions. A molecule is the smallest unit of a compound.
mixture - **🔰 VERIFIED ANSWERS🔰 ✔✔made of substances (elements and/or
compounds) mixed together in no fixed composition. A homogeneous mixture will appear
uniform throughout is sometimes called a solution. A heterogeneous mixture varies in its
composition (you will see distinct parts or phases).
Density - **🔰 VERIFIED ANSWERS🔰 ✔✔For irregularly-shaped solids:
1- take mass of solid (or given)
2- determine the volume of solid by displacement of water
Example: A solid weighing 25.22 grams is dropped into a graduated cylinder containing 15.6
mL of water. The water level rises to 25.0 mL. Calculate the density of the solid.
D = Mass = 25.22 g = 25.22 g = 2.7 g/mL
Volume (25.0 - 15.6)mL 9.4 mL
For liquids:
, 1- take the mass of the empty graduated cylinder
2- add volume of liquid (record the volume)
3- determine the mass of the liquid by added mass to container.
naming compounds, giving formulas------Naming Ionic Compounds - **🔰 VERIFIED
ANSWERS🔰 ✔✔For binary ionic compounds (meaning one metal with one nonmetal), we
name the metal and name the nonmetal with an -ide ending.
For these metals, we do not have to specify their charge when naming the compound.
specify their charge in the name. In these cases where the metal can have more than one
charge, name the metal, identify the charge of the metal using roman numerals in
parenthesis, and name the nonmetal with an -ide ending.
protons, neutrons and electrons - **🔰 VERIFIED ANSWERS🔰 ✔✔protons = atomic
number
Neutrons = mass number - atomic number
Electrons = protons (for any atom, which is neutral)
Temperature Conversions - **🔰 VERIFIED ANSWERS🔰 ✔✔°F = 1.8 (°C) + 32 or (°F -
32) = °C
1.8
and °C + 273.15 = K
Percent Composition - **🔰 VERIFIED ANSWERS🔰 ✔✔Mass Percent
Mass percent refers to the percent by mass of each element in the compound. Make sure to
add up the mass of each atom of element to get the total mass of each element first. (for
example, Na2SO4 would have 2 Na atoms, 1 sulfur and 4 oxygen atoms). Add the total mass
of all elements together to get the molar mass. Divide the total mass of each element by the
molar mass, multiply by 100, and there's your % mass for that element. Percent composition
should provide the mass percent of every element in the compound and thus, should total
100%.
