Questão 1
Questão
Which of the following is a physical property of paper?
Questão 2
Questão
Chemical properties can always be determined by simply touching or looking at a substance.
Questão 3
Questão
Boiling water is a chemical change.
Questão 4
Questão
Drying a wet dish with a towel is a physical change.
Questão 5
Questão
Which of the following are examples of physical changes?
Responda
-
A banana is sliced and put in a fruit salad.
-
An ice cube sits in the hot sun and melts into a puddle, then evaporates.
-
A slice of bread is left in the toaster too long and burns to a crisp.
-
A milk carton is left out of the refrigerator and turns sour.
Questão 6
Questão
You are examining a certain substance as part of an experiment. The substance's atoms are moving randomly and rapidly, and take the shape of the container they are placed in. When you open the container, the substance diffuses quickly into the air. Given this information, you conclude that the substance is a:
Questão 7
Questão
Which of the following are NOT properties of a solid?
Questão 8
Questão
Dry ice is the solid form of carbon dioxide, which lacks a liquid state. By which process is dry ice created?
Responda
-
deposition
-
freezing
-
condensation
-
sublimation
Questão 9
Questão
Which two changes of state result in a liquid?
Responda
-
Freezing
-
Sublimation
-
Melting
-
Condensation
Questão 10
Questão
When enough heat is added to most solids, they will either melt or sublimate.
Questão 11
Questão
Electrons have a positive charge.
Questão 12
Questão
"Average atomic mass" is the number of protons plus electrons in an atom.
Questão 13
Questão
Which of the following terms refers to the number of protons and neutrons in an atom's nucleus?
Responda
-
Mass number
-
Atomic number
-
Average atomic mass
-
Nuclear total
Questão 14
Questão
A given atom has no charge. It has an atomic number of 5. How many electrons does it have?
Questão 15
Questão
If an atom has an atomic mass number of 10, and you know it has 7 neutrons, the atomic number must be 3.
Questão 16
Questão
Which parts of an atom orbit around the nucleus?
Responda
-
Protons
-
Electrons
-
Neutrons
-
Protons and electrons
Questão 17
Questão
Electrons are negative, protons are positive, and neutrons have no charge.
Questão 18
Questão
A particular atom has two isotopes.
The mass of the first isotope, in amu, is 20.802, and its percent abundance is 42.5.
The mass of the second isotope, in amu, is 35.599, and its percentage abundance is 57.5.
What is the atom's average atomic mass?
Responda
-
29.310 amu
-
29 grams
-
13.783 amu
-
146.55 amu
Questão 19
Questão
Oxygen has three naturally occurring isotopes:
Mass of 15.995, natural abundance of 99.76%
Mass of 16.999, natural abundance of 0.038%
Mass of 17.999, natural abundance of 0.205%
What is the average atomic mass?
Responda
-
16.000 amu
-
15.9 grams
-
33.334 amu
-
15.8 amu
Questão 20
Questão
Atomic mass is measured in amu, a unit derived from the mass of carbon-12.