1.
Abbreviation for mole.
Correct Answer
mol
Explanation
The correct answer is "mol" which is the abbreviation for mole.
2.
SI unit used to measure the amount of a substance. (Like a dozen).
Correct Answer
mol
Mole
Explanation
The SI unit used to measure the amount of a substance is the mole (mol). The mole is similar to a dozen, as it represents a specific number of entities (in this case, atoms, molecules, or ions) just like a dozen represents a specific number of items. The mole is a fundamental unit in chemistry and is used to quantify the amount of a substance in a given sample. The term "Mole" is simply another way of referring to the unit "mol".
3.
6.02x10^{23} is known as:
Correct Answer
D. Avogadro's Number
Explanation
6.02x10^23 is known as Avogadro's Number. It represents the number of atoms, molecules, or particles in one mole of a substance. This constant is named after the Italian scientist Amedeo Avogadro, who proposed the concept of Avogadro's law, stating that equal volumes of gases at the same temperature and pressure contain an equal number of particles. Avogadro's Number is widely used in chemistry and is essential for calculations involving the mole and stoichiometry.
4.
Avogadro's number can be used to show:
Check all that apply.
Correct Answer(s)
A. Atoms
C. Molecules
F. Formula Units
Explanation
Avogadro's number, also known as the Avogadro constant, is a fundamental constant in chemistry that represents the number of particles (atoms, molecules, or formula units) in one mole of a substance. Therefore, it can be used to show the number of atoms, molecules, and formula units in a given amount of substance. It is not directly related to compounds, mass, or moles, so these options are not applicable.
5.
Mass in grams of one mole of any pure substance. (g/mol) Equal to the atomic mass.
Correct Answer(s)
Molar Mass
Molar
Explanation
The molar mass of a substance is the mass in grams of one mole of that substance. It is equal to the atomic mass of the substance. Molar mass is used to convert between the mass of a substance and the number of moles of that substance, and it is an important concept in chemistry for calculating various quantities in chemical reactions.
6.
To find the molar mass of a molecule you:
Correct Answer
A. Add up the pieces.
Explanation
To find the molar mass of a molecule, you need to add up the masses of all the individual atoms (pieces) in the molecule. Each element has a specific atomic mass, and by adding them together, you can determine the molar mass of the entire molecule. Multiplying, subtracting, or dividing the pieces would not give you the correct answer for the molar mass.
7.
Simplest whole-number ratio of atoms of elements in the compound.
________ Formula
Correct Answer
Empirical
Empirical Formula
Emperical
Emperical Formula
Explanation
Note: The correct spelling is empirical formula.
8.
If you have C6H12O6; What is the empirical formula?
Correct Answer
CH2O
Explanation
The empirical formula represents the simplest ratio of atoms in a compound. In this case, the compound C6H12O6 can be simplified by dividing all the subscripts by the greatest common factor, which is 6. After simplification, we get CH2O as the empirical formula.
9.
Assume you wlaways have ____ grams when calculating percentages of elements in a compound.
Correct Answer
100
Hundred
A Hundred
One hundred
Explanation
The given correct answer options all represent the same numerical value, which is 100. When calculating percentages of elements in a compound, it is assumed that you always have 100 grams as the base unit of measurement. This allows for easy comparison and calculation of the percentage composition of each element in the compound.
10.
To get the ratios of the empirical formula you divide by the _____ number.
Correct Answer
Smallest
The Smallest Number
Smaller Number
Least
Small
Explanation
To determine the ratios of the empirical formula, you divide by the smallest number. This is because the empirical formula represents the simplest ratio of atoms in a compound, and the smallest number in the ratio indicates the lowest whole number ratio of atoms present. Therefore, dividing by the smallest number allows us to obtain the correct ratios of the empirical formula.
11.
You have a compound.
BrFe4
Bromine makes up 23.7%. What is the percentage of Iron?
Correct Answer
76.3
76.3 percent
76.3%
Explanation
The percentage of Iron in the compound is 76.3%.
12.
You have the substance C6H12O6. You are trying to find the number of oxygen ions in 60 grams of the substancce. Fill in the blank.
60 gC6H12O6 1 mol ? O
-------------------- X ------------- X ---------------------
1 180.155 g 1 mol C6H12O6
Correct Answer
6
Explanation
In the given calculation, we are converting the mass of C6H12O6 (60g) to the number of oxygen ions. Since the molar mass of C6H12O6 is 180.155g/mol and there are 6 oxygen atoms in one molecule of C6H12O6, we can calculate the number of moles of C6H12O6 by dividing the mass (60g) by the molar mass (180.155g/mol). Since there are 6 oxygen atoms in one molecule of C6H12O6, the number of oxygen ions is equal to the number of moles of C6H12O6 multiplied by 6. Therefore, the answer is 6.