Introduction to Chemistry Final Exam

What statements is true about any element?

It can be identified on the basis of its properties, it has a unique set of properties, it is different from all other elements.

The mass number of an atom is its number of

protons plus neutrons.

Bohr's model of the atom differs from Rutherford's model in

the location of electrons

Rutherford's research involved

alpha particles and gold foil

Which element has atoms that could most easily lose one electron to become stable?

Potassium (K)

Which of these is the simplest relationship between the dependent variable and the independent variable?

linear

The state of matter that can change shape but not volume is

liquid

Why are Argon and Neon unlikely to form bonds with other elements?

with 8 valence electrons, they are chemically stable.

Aristotle thought that

all matter consists of 4 elements.

Which element is likely to be shiny and able to conduct electricity and heat?

Beryllium

When a fluorine atom gains an electron, it becomes a(n)

anion.

The particles of a(n) ______ solid have no definite pattern.

amorphous

A(n) ______ consists of atoms or molecules that spread out to fill their container.

gas

The sun and other stars consist of matter in the ______ state.

plasma

Amontons' law describes the relationship between the temperature and ______ of gases.

pressure

The law relating the volume and pressure of gases is ______ law.

Boyle's

The temperature at which is a solid changes to a liquid is its ______.

melting point

A solid changes directly to a gas in the process of ______ .

sublimation

The boiling point of water is ______ °C.

100

True or False: Making ice cubes with tap water is an example of a chemical change.

False

True or False: All changes in matter can be reversed.

False

True or False: Melting metal changes it into an entirely different substance.

False

True or False: The release of gas bubbles is a possible sign of a chemical change.

True

True or False: After a physical change, matter still has the same chemical properties.

True

The ability of a substance to combine chemically with other substances is called ______.

reactivity

All ______ has properties of mass and volume.

matter

The ability of matter to conduct electricity is a(n) ______ property of matter.

physical

A 20-kg object with a volume of 2 meters cubed has a density of ______.

10 kg/m^3

______ properties of matter can be measured only when matter changes to different substances.

chemical

The ability of matter to be attracted by a magnet is a(n) ______ property of matter.

physical

A change in the size or shape of matter is a ______ change in matter.

physical

A log burning is an example of a ______ change in matter.

chemical

92 of these occur naturally.

elements

Its parts can be separated by physical means.

mixture

These are a product of chemical joining of 2 or more atoms.

compounds

Made up of only one type of atom.

elements

A hot air balloon at 81,000 feet pops. Why ?

pressure was so low, volume increased and popped it.

How many independent variables does a good investigator use in his or her experiment?

one

Place the types of covalent bonds in order of DECREASING strength.

triple bond, double bond, single bond

What statement best describes what happens to ionic compounds when they are dissolved?

they are pulled apart by water molecules

A student is investigating how temperature affects bacterial growth. Which of these would be an appropriate hypothesis to formulate based on these variables?

an increase in temperature causes the rate of bacterial growth to increase

The atomic number of an atom is 10 and its mass number is 21. How many protons does the atom have?

10

The atomic number of an atom is 10 and its mass number is 21. How many neutrons does the atom have?

11

The atomic number of an atom is 10 and its mass number is 21. How many electrons does the atom have?

10

What is a chemical property of matter?

reactivity

Which component of the scientific method typically identifies experimental error?

the conclusions

A sodium atom has 2 electrons on the innermost electron level, 8 on the middle one, and 1 valence electron. A chlorine atom has 2 electrons on the innermost electron level, 8 on the middle one, and 7 valence electron. How many electrons would each of the atoms have once they join to form table salt (NaCl), and how are they arranged?

the sodium atom has 2 electrons on the innermost electron level and 8 valence electrons, and the chlorine atom has 2 electrons on the innermost electron level, 8 on the middle one, and 8 valence electrons.

What would happen to their electrons if potassium combined with iodine to form a molecule?

Potassium would lose one electron and become a positive ion. Iodine would gain one electron and become a negative ion.

A student wants to investigate if there is a relationship between car tire friction and air pressure in tires. If the student is following the scientific method, what should she do next?

Conduct research to obtain any information that already exists on this topic.

What would the chemical formula be for a compound composed of iodine and potassium?

KI

How many valence electrons does Phosphorus have?

5

When following the scientific method, which step does a scientist typically take after drawing a conclusion about the validity of a hypothesis?

analyzing the data to check the conclusions

If an object has a mass of 42 kg and a volume of 2 m^3, what is its density?

21 kg/m^3

In the planetary model, the planets represent

electrons

A student sets up an experiment to determine how much time will elapse before equal samples of water at 20 ° C become solid if placed in freezers set at four different temperatures. Which are the independent and dependent variables in this experiment?

the various temperatures in the freezers, and the time it takes the water to freeze

An astronaut on the space station tests whether gravity affects the productivity of tomato plants. What is the independent variable in this experiment?

the force of gravity affecting the plants on the space station

Dalton's atomic models were most similar to

bowling balls

In the plum pudding model of the atom, the raisins represent

electrons

In an experiment, why is an independent variable is sometimes called a "manipulated variable"?)

it is the variable the investigator changes.

Two students are measuring the temperature of water by using different measuring tools. They take four measurements of the temperature of the water without changing any other variables. Which of their tables would contain the most precise data?

the table with the data that is closer together in value

What is an example of a chemical reaction?

wood burning

Which elements have a full outer energy level?

neon and helium

The history of the atom began almost

2500 years ago

Atomic theory was introduced around

450 BC

What is an example of a physical change?

boiling water

What kind of bond would form if potassium combined with iodine to form a compound?

ionic bond

Which element is most likely to bond with other elements? Why is this element so reactive?

sodium, because it has only 1 valence electron

What is wrong with a table that goes in this order: Question, Research, the Experiment, Plotting Data, then Drawing Conclusions.

the scientist did not develop a hypothesis

J.J. Thomson discovered the

electron

If sodium loses one electron and chlorine gains one electron, how many valence electrons do sodium and chlorine now have?

Sodium and chlorine each have 8 valence electrons.

Chemical properties of matter include

ability to rust

Atoms in a diagram that are all using a pooled group of electrons are

pooling valence electrons

A student observes a boulder rolling down a hill. He hypothesizes that a boulder with greater mass will roll down the same hill faster. He designs an experiment to test this hypothesis. In the experiment, what should be the independent variable?

the mass of the boulder

What compound has the strongest covalent bond?

N2

The smallest particles of an element that still have the element's properties are

atoms

Which of these actions will most likely occur during the data analysis phase of the scientific method?

calculating statistics about the data

Which energy level has the least energy?

n = 1

Which statement is true about the nucleus of an atom?

it makes up most of the atom's mass

How many electrons are needed to give Silicon and and Phosphorus stable electron configurations?

Silicon needs 4 electrons to become stable. Phosphorous needs 3.

Matter in the plasma state is found in

lightening

Water is a molecule composed of one oxygen and two hydrogen atoms. How does forming a chemical bond affect the stability of these atoms?

forming chemical bonds make the atoms more stable.

A student measured the mass of a candle before and after burning it and found the mass to be lower after burning than before. How can this be best explained?

some of the products were gases which escaped and were not measured.

Oxygen has six valence electrons. Explain why a molecule of water has eight valence electrons.

the electron in each hydrogen atom's outer energy level completes oxygen's outer energy level and bonds the atoms together.

A line graph shows data from an experiment in which the independent variable is the volume of a

gas and the dependent variable is the pressure on the gas. The slope of the line falls from left to right. What does an analysis of the graph reveal about the relationship between the volume of a gas and the pressure on it?

as volume decreases, pressure increases

Rutherford concluded from his experiments that

electrons orbit the positively charged nucleus and all the positive charge of an atom is concentrated in the center

What is not an example of a step in the scientific metod

eliminate bad data

A possible sign that a chemical change has occurred is a change in

color

Atoms of a given element all have the same number of

protons

Fluorine (F), chlorine (Cl), bromine (Br), and iodine (I) are elements that share similar chemical

properties. Called halogens, these elements are highly reactive. They form stable ionic compounds with metals, such as sodium chloride (NaCl), potassium iodide (KI), and calcium fluoride (CaF2). They can also form one single, stable covalent bond with a nonmetal. They are part of many covalently bonded organic compounds, such as chloroform. Due to their reactivity, halogens have wide applications and industrial uses. In terms of valence electrons, why are halogens highly reactive, allowing them to form compounds easily?

Halogens are reactive because they have seven valence electrons and will gain one from a metal. This allows them to become chemically stable.

Aristotle thought there were four elements, including

air

Carlos has to decide on a science project. He hasn't had much success getting consistent data in

class. His teacher says he needs to do a better job of controlling variables. He wants to choose an investigation in which he can easily control the variables. What is an investigation he should choose?

determine how ramp height affects how far a marble rolls in an indoor setting.

Matter cannot be created or destroyed according to the law of

conservation of mass

Bohr's research focused on

electrons

The theory that all matter consists of constantly moving particles is known as the

kinetic theory of matter

Observation or Inference: The dance last night ended at 11 :30 p.m.

observation

Observation or Inference: The dance ended because the chaperones were tired.

inference

Observation or Inference: When salt was poured on the ice, the ice melted.

observation

Observation or Inference: When salt is put on ice, the ice melts because the salt is hot.

inference

Observation or Inference: The snow cone the little girl was eating was green.

observation

Observation or Inference: The little girl with the snow cone likes lime flavoring.

inference