Chemistry

You go out to dinner and the bill comes to $ 30.72. How much should you tip if you want the tip to be 20.0 % of the bill?

$ 6.14

Chemical reaction:

- Carbon dioxide is produced by the combustion of gasoline in an automobile engine. - Oxygen gas changes to ozone during thunderstorms. - When coal, oil, and natural gas are decomposed in landfills they produce methane gas.

Physical change

- Fog forms from water vapor when the temperature drops below the dew point. - Freezing rain develops when a warm air mass overrides a cold air mass.

On the basis of Rutherford's experimental observations, which of the following statements describes the structure of the atom according to Rutherford's atomic model?

- In an atom, negatively charged electrons are dispersed in the space surrounding the positively charged nucleus of an atom. - In an atom, the positive charges are located in a small core within the atom called the nucleus.

Which of the following properties of a glass are physical properties?

- It is transparent. - It has a mass of 5.4 g. - It is brittle.

Which of the following properties of aluminum are chemical properties?

- It reacts with chlorine to form aluminum chloride. - In moist air it combines with oxygen to form aluminum oxide.

In a laboratory experiment, a fermenting aqueous solution of glucose and yeast produces carbon dioxide gas and ethanol. The solution was heated by burning natural gas in a Bunsen burner to distill the ethanol that formed in the flask. During the distillation, the ethanol evaporated and then condensed in the receiving flask. The flame of the burner was kept too close to the bottom of the flask and some of the glucose decomposed into a black carbon deposit on the inside of the flask. During this experiment the following changes occurred. Which of these changes involved a physical change and not a chemical change?

- evaporation of ethanol - condensation of ethanol

You are given a sample resembling silver. Which of the following properties could be used to help determine whether the sample is really silver?

- the density of the sample - the melting point of the sample

In a college of exactly 2940 students, exactly 45 % are male. What is the number of female students?

0 + 1i female students

A specific brand of gourmet chocolate candy contains 7.00 g of dietary fat in each 22.7-g piece. How many kilograms of dietary fat are in a box containing 1.00 lb of candy?

0.140 kg

Dalton's Atomic Theory

1. Each element is composed of extremely small particles called atoms. 2. All atoms of a given element are identical to one another in mass and other properties, but the atoms of one element are different from the atoms of other elements. 3. Atoms of an element are not changed into atoms of a different element by chemical reactions; atoms are neither created nor destroyed in chemical reactions. 4. Compounds are formed when atoms of more than one element combine; a given compound always has the same relative number and kind of atoms.

Convert the number 0.000127 to scientific notation, then enter the answer using a power of 10. You can select the button for scientific notation from the templates menu.

1.27×10^−4

1.2 ns

1.2×10−9 s

141 pm

1.41×10−10 m

14 fs

1.4×10−14 s

18.7 ×10−10 s

1.87 nanoseconds

18.7 ×1011 m

1.87 terameters

If you have a quarter of a pie and you cut it in half, what fraction of a pie would each slice represent?

1/8

While in Europe, if you drive 105 km per day, how much money would you spend on gas in one week if gas costs 1.10 euros per liter and your car's gas mileage is 23.0 mi/gal ? Assume that 1euro=1.26dollars.

104 dollars

Al3+

13 protons, 10 electrons

In Europe, gasoline efficiency is measured in km/L. If your car's gas mileage is 25.0 mi/gal , how many liters of gasoline would you need to buy to complete a 142-km trip in Europe? Use the following conversions: 1km=0.6214mi and 1gal=3.78L.

13.3 L

147 nm to μm

147 nm = 0.147 μm

An atom of sulfur is represented by 33/16 S. How many neutrons are in the nucleus of this atom?

17

The conversion factor relating feet to meters is 1ft=0.305m. Keep in mind that when using conversion factors, you want to make sure that like units cancel leaving you with the units you need. You have been told that a certain house is 164 m2 in area. How much is this in square feet?

1760 ft2

1898 mg to kg

1898 mg = 1.898×10−3 kg

40/19 K

19 protons, 21 neutrons

Boron has only two naturally occurring isotopes. The mass of boron-10 is 10.01294 amu and the mass of boron-11 is 11.00931 amu . Use the atomic mass of boron to calculate the relative abundance of boron-10.

19.9 %

198 km to cm

198 km = 1.98×107 cm

What is the ratio of hydrogen atoms (H) to oxygen atoms (O) in 2 L of water? Enter the simplest whole number ratio in order of hydrogen to oxygen, respectively.

2:1

31.7 ×105 g

3.17 megagrams

31 μm

3.1×10−5 m

A particular brand of gasoline has a density of 0.737 g/mL at 25 ∘C. How many grams of this gasoline would fill a 13.4 gal tank (1US gal=3.78L)?

3.73×104 g

A sprinter set a high school record in track and field, running 200.0 m in 21.2 s . What is the average speed of the sprinter in kilometers per hour?

34.0 km/h

Specify the number of protons, neutrons, and electrons in the neutral atom bromine-80.

35 protons, 45 neutrons, 35 electrons

35.47 Tm to Gm

35.47 Tm = 3.547×104 Gm

3549 cm3 to L

3549 cm3 = 3.549 L

A block of metal has a width of 3.2 cm, a length of 17.1 cm, and height of 4.7 cm . Its mass is 1.2 kg . Calculate the density of the metal.

4.7 g/cm3

You have 125 g of a certain seasoning and are told that it contains 58.0 g of salt. What is the percentage of salt by mass in this seasoning?

46.4 % salt by mass Percentage by mass can be applied to any unit of mass. For example, 46.4 % salt by mass means that there is 46.4 mg of salt per 100 mg of mixture, 46.4 mg salt100 mg mixture, or 46.4 lb of salt per 100 lb of mixture, 46.4 lb salt100 lb mixture, etc.

Which of the following are equal to 5×1010?

500×10^8, 0.5×10^11, 50×10^9

The law of conservation of mass states that mass is neither created nor destroyed during a chemical reaction. This can be gleaned from the third postulate in Dalton's series. Magnesium oxide decomposes into magnesium and oxygen. If 16.12 g of magnesium oxide decomposes to form 9.72 g of magnesium, what mass of oxygen gas is also released in the reaction?

6.40 g

extensive property

varies with the amount of the sample. ex: has a mass of 77.83 g, has a volume of 7.42 mL

The conversion factor relating miles to meters is 1mile=1610m. The speed of light is 3.00×108 m/s. How fast is this in miles per hour (miles/h)?

6.71×108 miles/h

N3−

7 protons, 10 electrons

Suppose that a certain fortunate person has a net worth of $75.0 billion ($7.50×10^10). If her stock has a good year and gains $3.20 billion (3.20×109) in value, what is her new net worth?

7.82×10^10 dollars

85.8× 10−7 L

8.58 microliters

Boron has only two naturally occurring isotopes. The mass of boron-10 is 10.01294 amu and the mass of boron-11 is 11.00931 amu . Use the atomic mass of boron to calculate the relative abundance of boron-11.

80.1 %

Suppose that this individual now decides to give one-eighth of a percent (0.125 %) of her new net worth to charity. How many dollars are given to charity?

9.78×10^7 dollars

Determine the number of protons and the number of neutrons in uranium-235.

92 protons, 143 neutrons

What is the difference between a homogeneous and a heterogeneous mixture?

A homogeneous mixture has the same composition throughout, while a heterogeneous mixture has different compositions in different regions.

Cations: Cations that make multiple ions are distinguished by Roman numerals.

Fe3+ [iron(III)]

Anions: Halogens and transition metals that can form up to four oxoanions require distinguishing prefixes.

ClO− (hypochlorite) ClO2− (chlorite) ClO3− (chlorate) ClO4− (perchlorate)

Anions: If the element forms only one ion, add ide to the element name.

Cl− (chloride)

The ideal gas equation is PV=nRT where P is pressure, V is volume, n is the number of moles, R is a constant, and T is temperature. You are told that a sample of gas has a pressure of P = 861 torr , a volume of V = 4360 mL , and a temperature of T = 296 K . If you use R = 8.206×10−2 L⋅atm/(K⋅mol) , which of the following conversions would be necessary before you could find the number of moles of gas, n, in this sample? Check all that apply.

Convert the pressure to atmospheres (atm), Convert the volume to liters (L).

Blue vitriol is commonly used in industrial dyeing processes. What is the chemical formula for blue vitriol, whose systematic name is copper(II) sulfate?

CuSO4

Cations: If the element forms only one ion, simply name the element.

K+ (potassium)

What is the chemical formula for potassium permanganate?

KMnO4

What is the chemical formula for the base potassium hydroxide?

KOH

Cations: Polyatomic ions have special names.

NH4+ (ammonium)

What is the formula for the compound nitrogen monoxide?

NO

Sodium carbonate is used in the manufacture of paper. What is the chemical formula for this compound?

Na2CO3

What is the formula for the compound tetraphosphorus decoxide?

P4O10

Anions: When there are only two oxoanions in a series, use ite for the anion with fewer oxygen atoms and ate for the anion with more oxygen atoms.

SO4 2− (sulfate) SO3 2− (sulfite)

77 K to ∘F (temperature of liquid nitrogen)

T = -321 ∘F

−109∘F to ∘C (temperature of dry ice)

T = -78.3 ∘C

32 ∘F to ∘C (temperature at which water freezes)

T = 0 ∘C

98.2 ∘F to K (body temperature)

T = 309.9 K

What is the difference between a crystalline solid and an amorphous solid?

The atoms or molecules of crystalline solid are arranged in patterns with long-range, repeating order. The atoms or molecules of amorphous solid do not have any long-range order.

What is the main goal of chemistry?

The main goal of chemistry is to seek to understand the behavior of matter by studying the behavior of atoms and molecules.

Which of the following conclusions are correct about Rutherford's experiment?

The majority of the space inside the atom is empty space, the mass of an atom is concentrated at the nucleus, the atom contains a positively charged nucleus, positive charge is condensed in one location within the atom.

What is the volume, in milliliters, of 6.78 g of acetone?

V = 8.63 mL

Does the size of a degree differ among celsius, Fahrenheit, and kelvin?

the size of the degree is the same in the Kelvin and the Celsius scales

heterogenous mixture

a heterogeneous mixture composed of the two elements

homogenous mixture

a homogenous mixture composed of the two elements

pure substance

a pure substance (a compound) composed of the two elements (in a one-to-one ratio)

NH4Br

ammonium bromide

What is the systematic name of NH4ClO3?

ammonium chlorate

An atom has a mass number of 30 and 16 neutrons. What is the atomic number of this atom?

atomic number = 14

What is the name of the base that has the formula Ba(OH)2?

barium hydroxide

Ba(ClO)2

barium hypochlorite

naming hydrocarbons: 4

but

What is the density, d, of a substance with a volume of V = 21.4 cm3 and a mass of m = 67.8 g ?

d = 3.17 g/cm3

naming hydrocarbons: 10

dec

What is the name for the compound N2H4?

dinitrogen tetrahydride

hydrocarbons: alkenes (-ene)

double bonds

naming hydrocarbons: 2

eth

In chemical reactions, matter is neither created nor destroyed.

ex of: law

When a match burns, heat is evolved.

ex of: observation

When iron rusts in a closed container, the mass of the container and its contents does not change.

ex of: observation

All matter is made of tiny, indestructible particles called atoms.

ex of: theory

alkali metals

group 1A, all reactive

alkaline earth metals

group 2A, fairly reactive

halogens

group 7A, very reactive

noble gases

group 8A, mostly unreactive

SnCl2

tin(II) chloride

hydrocarbons: alkynes (-yne)

triple bonds

naming hydrocarbons: 7

hept

naming hydrocarbons: 6

hex

hydrocarbons: aromatic

hydrocarbons containing C6 "benzene" ring

intensive property

independent of the amount of the sample. ex: begins to melt at 961.78 degrees Celsius, matte gray in color, has a density of 10.49 g/mL

What is the name for the compound IF7?

iodine heptafluoride

ionic vs molecular

ionic and molecular compounds have very different physical properties. Whereas ionic compounds tend to form hard crystalline solids, molecular compounds (sometimes called covalent compounds) can be gases, liquids, or solids.

ionic bonds

ionic bond results from a transfer of one or more electrons from one atom to another. (not molecular) As a general rule, ionic bonds occur between a metal and a nonmetal atom.

What is the systematic name of PbO?

lead(II) oxide

What is the mass, in grams, of 28.70 mL of acetone?

m = 22.55 g

What is the systematic name of Mg(NO3)2?

magnesium nitrate

Name the hydrate MgSO4⋅7H2O.

magnesium sulfate heptahydrate

The atomic number of nitrogen is 7. What is the mass number of a nitrogen atom with 6 neutrons?

mass number = 13

Phosphorus forms several compounds with oxygen, including diphosphorus trioxide and diphosphorus pentoxide. A decomposition of a sample of diphosphorus trioxide forms 1.29 g phosphorus to every 1.00 g oxygen. The decomposition of a sample of diphosphorus pentoxide forms 0.775 g phosphorus to every 1.00 g oxygen. Show that these results are consistent with the law of multiple proportions.

mass of phosphorus to 1.00 g oxygen in diphosphorus trioxidemass/ phosphorus to 1.00 g oxygen in diphosphorus pentoxide= 1.29g/0.775g=1.66

HgCl2

mercury(II) chloride

naming hydrocarbons: 1

meth

A sample of concrete contains cement, gravel, crushed rocks, sand, and water. Each of these contains different metals and minerals and hence has different colors and different properties. Which term or terms could be used to describe this sample of concrete?

mixture, heterogeneous mixture

A sample of wine consists of water, sugar, some amount of ethyl alcohol, and grape juice. These ingredients blend together uniformly to give clear and tasty wine. Which term or terms could be used to describe this sample of wine?

mixture, homogenous mixture, solution

A certain solution has a molarity of M = 3.96 mol/L and has a volume of V = 0.530 L . What is the value of n?

n = 2.10 mol

naming hydrocarbons: 9

non

covalent bond

occurs when atoms share electrons. (molecular) As a general rule, covalent bonds occur between two nonmetal atoms

naming hydrocarbons: 8

oct

naming hydrocarbons: 5

pent

naming hydrocarbons: 3

prop

A cylinder is filled with pure nitrogen dioxide. Which term or terms could be used to describe the contents of this cylinder?

pure chemical substance, compound

A silver necklace is made from a pure sample of silver that is free of impurities. Which term or terms could be used to describe this sample of silver?

pure chemical substance, element

hydrocarbons: alkanes (-ane)

single bonds

NaClO4

sodium perchlorate

The equation for photon energy, E, is E=hc/λ, where h = 6.626×10−34 J⋅s (Planck's constant) and c = 2.99×108 m/s (the speed of light). What is the wavelength, λ, of a photon that has an energy of E = 4.57×10−19 J ?

λ = 4.33×10−7 m