Homework problems
What is the mass number for an atom of barium containing 56 protons and 79 neutrons?
135
The number 64800 has ___ significant figures.
3
How many significant figures does the number 48.050 have?
5
Which of the following numbers contains five significant figures?
50.260
Write the chemical formula for aluminum oxide?
Al₂O₃
Write the chemical formula for barium bromide?
BaBr₂
Provide the correct IUPAC name for C₂O₃?
Dicarbon trioxide
Provide the correct IUPAC name for H₂O?
Dihydrogen monoxide
Which has the incorrect name-formula combination?
Iodine trifluoride - IF
Write the chemical formula for lithium chloride?
LiCl
Which scientist determined the charge of the electron?
Robert Millikan
Which of the following transition metals would be expected to have the smallest atomic radius?
Ruthenium (Ru)
Calculate the answer and report the correct number of significant figures. 0.02 cm x 2.371 cm
0.02 cm×2.371 cm=0.04---742 cm2=0.05 cm2
Calculate the answer and report the correct number of significant figures. 1.030 g ÷ 2.87 mL
1.030 g2.87 mL=0.358------885 g/mL= 0.359 g/mL
A volumetric flask contains 100.0 mL of water. This volume is added to a beaker containing 175 mL of water. Choose the value that expresses the new total volume of water in the beaker with the correct number of significant figures.
100.0mL+175mL= 275mL
What is the mass number for an atom of mercury-containing 80 protons and 119 neutrons?
199
The number 4.0 × 10⁵ has ___ significant figures
2
Iron exists in nature as a mixture of predominantly three isotopes: ⁵⁴₂₆Fe (53.94 amu), ⁵⁶₂₆Fe (55.93 amu), and ⁵⁷₂₆Fe (56.94 amu). If the most common isotope, ⁵⁶₂₆Fe, accounts for 91.75% of iron atoms, and the average atomic mass of iron is 55.85 amu, what is the percent abundance of the rarest of these three isotopes of iron?
2.81 %
Chlorine exists in nature as a mixture of two stable isotopes, Cl-35 and Cl-37. If the atomic mass of chlorine is given as 35.45 amu, which of the following represents the percent abundance of Cl-37?
23%
A patient needs 25.0 μg of Synthroid each day. The pharmacy only has Synthroid that is 0.025 mg per scored tablet. How many tablets should be taken each day by the patient?
25.0 μg×1 mg1000 μg×1 tablet0.025 mg= 1.00 tablet
How many protons are in an atom of Cu?
29
A beaker of water has an initial mass of 455.2 g. After it has been left uncovered for several days, some of the water has evaporated. The new mass of the beaker is found to be 422.55 g using a more precise balance. Choose that value that expresses the mass of the evaporated water using the correct number of significant figures.
455.2g−422.55g= 32.7g
An unknown element X has the following isotopes: ⁵²X (91.00% abundant), ⁴⁹X (8.00% abundant), ⁵⁰X (1.00% abundant). What is the average atomic mass in amu of X?
51.7 amu
What is the atomic number for an element whose mass number is 145, which contains 85 neutrons per atom?
60
What is the atomic number for an element whose mass number is 180, which contains 107 neutrons per atom?
73
Write the chemical formula for aluminum fluoride?
AlF₃
Which postulate(s) of Dalton's atomic theory of matter is/are NOT true?
All atoms of a given element are identical Atoms are indestructible.
Provide the correct IUPAC name for AlF₃.
Aluminum fluoride
Provide the correct IUPAC name for BaBr₂?
Barium bromide
Write the chemical formula for barium nitride?
Ba₃N₂
Provide the correct IUPAC name for BBr₃?
Boron tribromide
Write the chemical formula for calcium hydride?
CaH₂
Write the chemical formula for calcium oxide?
CaO
Write the chemical formula for calcium nitride?
Ca₃N₂
Write the chemical formula for calcium phosphide?
Ca₃P₂
Write the chemical formula for cadmium chloride?
CdCl₂
Provide the correct IUPAC name for CuF₂?
Copper(II) fluoride
Provide the correct IUPAC name for N₂S₃?
Dinitrogen trisulfide
Which scientist developed the nuclear model of the atom?
Ernest Rutherford
The accepted value for the density of iron is 7.9 g/mL. Which of the following sets of experimental data for the density of iron is the most accurate?
Group 1: 7.98 g/mL, 7.85 g/mL
Which one of the following would be a physical property of glucose?
In its pure form, it is a white powder.
Which one of the following would be a chemical property of a sample of neon gas?
It is inert
Which has the correct name-formula combination?
Manganese(II) sulfide - MnS
Provide the correct IUPAC name for (Hg₂)₃N₂?
Mercury(I) nitride
Rutherford's gold foil experiment determined that?
Most of the space in an atom is empty except for a concentrated area called the nucleus.
Neutral atoms of all isotopes of a given element have the same?
Number of electrons
Provide the correct IUPAC name for RnF₂?
Radon difluoride
Provide the correct IUPAC name for AgF?
Silver fluoride
Which of the following metals would be expected to have the smallest atomic radius?
Tantalum (Ta)
The Millikan oil drop experiment determined?
The charge of the electron
The cathode ray tube experiment determined?
The existence of electrons
What does the mass number of an atom represent?
Total number of protons and neutrons in the atom
If you were given the task of measuring 75 milliliters of a liquid, which measuring device would you use?
a 100-milliliter graduated cylinder
Which of the following is a pure substance that can be broken down into simpler substances by chemical means?
compound
You measured the mass of a dry powder on a balance to be 23.76 g. What would you report as the uncertainty of this measurement?
± 0.01
Which of the following pairs represent isotopes?
²⁸Si and ²⁹Si
Which of the following would be an isotope of ¹⁴N?
¹⁶N
Which of the following atoms has the same number of neutrons as ⁵⁹Ni?
⁶⁰Cu
