CHEM FINAL

all chem questions

chemsitry is

the study of matter and the changes it undergoes

green chemsitry uses

materials and processes that are intended to prevent or reduce pollution at its source

a scientific hypothesis is

tentative

which of the following is not true for scientific law

it explains observeed scientific data

a chemsit employed by an airplane manufactorer investigates new adhesives for the purpose of building airplanes withut rivets. she is engages in

applied research

joe conducts an experiment to test the effectiveness of a new drug for cancer. which of the following variables would be easiest to control?

amount of drug administered

mass is

measurement of the amount of matter

which of these is a chemical change?

silkworms convert mulberry into silk

a liquid is characterized by

indefinite shape and definite volume

6 ug is equal to

.000006

molasses is a byproduct of the refining of sugar from sugar cane. the specific composition of molasses varies depending upon the source of the sugar cane. which one of the following is the best classification of molasses?

mixture

a substance that cannot be broken down by a chemical means into simpler substances is called

element

aftr a yellow solid is dissolved in water, the liquid appears to be uniformly yellow throughout. this yellow liquid is best classified as

homogenous mixture

the species represented by CO is

a molecule made up of carbon and oxygen

32g of sulfur will react with 48g of oxygen to produce 80g of sulfur trioxide. if 64g of sulfur and extra oxygen are placed into a sealed container and allowed to react, what is the mass of the material in the container after the reaction is completed?

160g

in the SI system fo measurement the unit of mass is the

kilogram

which of of the following statements is not a correct statement of the law of conservation of mass?

the mass of a system is dependent upon chemical reactions that may occur

a student measures 10.5g of mercury oxide into an open test tube and heats the tube. the heat cause the mercury oxide to decompose into mercury and oxygen. after reaction, the student finds the mass of the contents of the tuber to be 9.7g. which one of the following describes this observation?

.8g of oxygen gas are lost from the tube

heptane is always composed of 84% carbon and 16%hydrogen. this illustrates the law of

definite proportions

which of the following was not explained by daltons atomoic throry?

the law of conservation of mass

which one of the following is not part of daltons atomic theory?

atoms change into other atoms in chemical reactions

which set of compounds illustrates the law of multiple proportions?

CH4, C2H6, C3H8

one mole of carbon is equal

avagadro’s number, all of the above

mendeleev arranged element in the periodic table primarily in order of their

atomic masses

the box for an element on the periodic table will include all of the following information about an element except

the proportion of the element in a compound

all of the following are molecules except

H

If drops of water are subdivided to the ultimately smallest drops possible, what is the smallest particle of water that retains the chemical and physical properties of water?

molecule

hydrogen peroxide decomposes into watr and oxygen when exposed to hat or light. a tightly capped bottle of hydrgoen peroxide is placed on a mass scale and exposed to light for three weeks. the mass recording on the scale does not change. this is an example of

the law of conservation of mass

Identify if it is a chemical or physical change:

Chloroform boils at -34C

toast burns when left in a toaster

nitrogen is put in chip bags because it is inert

diamond is the hardest substance on earth

1. physical

2. chemical

3. chemical

4. chemical

an anion

is a negatively charged ion

a stream of electrons in a magnetic field would

be attracted towards the positive electrode

based upon the experiments of his coworkers and his gold foil experiement, rutherford proposed that

nucleus is positiely charged, empty space, etc.

all of the above

the difference in mass between protons and neutrons is generally regarded

as insignificant

the neutron has

the same aprox. mass as a proton but no charge

how many protons in a silver atom?

47

an atom of chlorine-37 has

17 protons and 20 neutrons

the speciic pattern of colors emitted by excited atoms is called a

line spectrum

as the energy level of an electron increases, the electrons distance from the nucleus, on average

increases

the lines in an atonomic line emission spectrum are due to

movement of electrons from higher energy states to lower energy states in atoms

which orbital will have the lowest energy?

4s

in which group do all atoms have 2 valence electrons?

alkaline earth metals

a sodium ion Na+, is isoelectronic to

neon atom

an atom with 7 valence electrons belongs to the _____ group

halogen

the number of electrons in a bromide ion, Br-, is

36

with respect to chemical bonding, which particles play the msot active role?

valence electrons

the attraction between positive and negative ions is known as

ionic bond

covalent bonds generally form between

nonmetals

an oxide ion is

O2-

calcium reacts with chloride to form

CaCl2

in reactions to form ionic compounds, metals generally

lose electrons

which contains 14 neutrons

28/14 Si

which one of the following has the lowest electronegativity

sodium

isotopes have a differ in the number of ____ while ions differ in the number of _____

neutrons; electrons

when the equation below is balanced, the coefficient of copper is :

Cu+AgNO3—> Cu(NO3)2+Ag

3

When the equation below is balanced, the coefficient of iron is:

Fe+O2—> Fe2O3

4

the label which indicatess that a substance is a liquid is

(l)

when 3 liters of oxygen gas and excess hydrogen gas react to form water at a constant temperature and pressure, how many liters of water vapor will be formed?

2H2(g)+O2(g)—>2H2O(g)

6

the law of combining volumes applies only to

gases

which of the following does not contain avagadros number of particles?

5g of boron

Diethyl ether has a formula (C2H5)2O

74.1g/mole

Molarity is a measure of

the concentration of a solute in a solution

How many liters of a .5M NaOH solution are needed in order to have 3.0 moles of NaOH?

6L

Which of the following is correct, according to avagadros number hypothesis?

at 0C and 1 atm pressure, equal volume of gases contian the same number of molecules

A one molar solution id a solution that contains one mole of solute in

one liter of solution

In a mixture of sugar dissolved in water, the resulting combination is a

solution

how many moles of (NH4)2S are there in 80g of (NH4)2S

1.17

Which of the following temperatures are the same?

melting point=freezing point

the process by which a liquid is converted to gas is called

vaporization

The temperature at which a liquid boils is the boiling point of the liquid. the boiling point is an indication of the intermoloecular forces that hold the matter in the liquid state. Water, H2O, boils at 100C. Ethanol C2H6O boils at 78C. Ammonia, NH3, boils at 33C. Which one of the following ranks the intrmolecular forces in these liquids from the strongest to the weakest.

water> ethanol> ammonia

Which of the following ranks the three states of matter from least to most orderede?

gas< liquid< solid

which of the following processes involves the removal of energy (heat)?

condensation

Ionic compounds have strong forces between particles. this means that generally ionic compounds are ___ at room temperature

solid

which of the following is not a property of an ionic compound? ionic compounds generally

condensation g->l

which of the following compounds will have the lowest melting point?

F2

water is a liquid at room temperature while methane is a gas. which statement compares the intermolecular forces in these molecules correctly?

the intermolecular forces in water are stronger than those in methane

which of the following is not a postulate of the kinetic- molecular theory?

the molecules of a gas are strongly attracted to each other

At STP, 22.4 liters of argon gas, Ar, will have a mass of

39.9g

at a given temp and pressure, the volume of a gas is directly proportiomal to the amount of gas present. this is a statement of

avagadros law

which states of matter experience intermolecular forces?

solid and liquid

which is not a characteristic of bases?

turn litmus paper red

many medicines have a bitter taste which manufacturers attempt to disguise. many medicines are probably

bases

which of the following is not true of arrhenius theory?

acids are defined as compounds that produce OH- ions in water solutions

Which of the following is a correct definition of an acid that is not dependent upon the solvent?

acids are proton donors

all of the following are bases except

HNO3-

what is the formula for strontium hydroxide?

Sr(OH)2

hydroflouric acid is classified as a weak acid in water. this means that it produces

only a fraction of the max number of possible hydronium ions

an acid is strong if it

ionizes completely in water

what is produced in an acid-base neutralization reaction?

a salt and water

a solution of toilet bowl cleaner has a pH of 6. the solution is

somewhat acidiic

a salt that conducts electricity in water is ___

electrolyte

an unknown substance is added to a solution and the pH decreases. the substance is best described as a

acid

all antacids are

bases

which of the following is bronsted-lowry base and not an arrhenius base

NH3

a buffer

all of the above are true. critical to living organisms, made up of weak acid and conj. base. etc

what is the conjugate base of HSO3-

SO3²-

what would you add to a solution of hydrocyanic acid HCN, to make a buffer solution?

CN-

the source of the energy produced by the sun is

the fusion of primarily hydrogen

the process of alpha decay results in what change in the atomic number?

a decrease of 2

which type of radioactive emission is very similar to X-rays?

gamma ray

what does not describe the ionizing radiation?

ionizing radiation can affect blood sugar levels and causes diabetes