Semester I Review

ANSWERS

Semester I Review

How many sig-figs are found in each number?0.345 33005 4300 13.002 40.00023 2

Semester I Review

Round each number to three sig-figs.45678 457000.002894 0.0028923.76 23.8100.5 100.56.799 56.8

Semester I Review

Which of the following is a mixture.Pure water compoundClean air homogenous mixture Iron (II) oxide compoundSalt water homogenous mixtureCarbon dioxide compound

Semester I Review

Which of the following is a chemical change.Cutting paper physicalBoiling water physicalRusting iron chemicalBurning gasoline chemical

Symbol Mass # Atomic # Protons Neutrons Electrons

X - _25__ 25 10 10 15 10

Y - 35 35 14 14 21 14

Z - _56__ 56 25 25 31 25

Complete the table using the given numbers

Semester I Review

Calculate the average atomic mass given the following data: element Y has three isotopes 35.0% = 23.5 amu, 55.0% = 25.0 amu and 10.0% = 26.0 amu.

(35x23.5) + (55x25.0) + (10x26.0) = 24.6

100

Semester I Review

25.0 grams of a given metal displaces 44.2 mL of water; what is the density of the metal?

25.0g/44.2mL = 0.566g/mL

Semester I Review

What did each scientist contribute to the development of the modern atom.Dalton = proof of the atomThomson = cathode rays are electronsRutherford = dense positive nucleus,

electrons outside nucleus, atom mostly empty space

Milliken = mass to charge ratio of the electron

Trial # Measurement True Value = 34.50

1 34.56

Accurate and

precise

2 34.45

3 34.78

Determine if the data below is accurate, precise, both, or neither

Calculate the percent error using the average of the measurements. (34.60 – 34.50) x100 = 0.2899%

34.50

Semester I Review

1. The splitting of a nucleus is known as ___fission _____.

2. The combining of two small nuclei to form a larger one is known as ____Fusion______.

3. Give the formula of an alpha particle and beta particle.

He42 0

1

Semester I Review1. Decay of polonium-218 by alpha ()

emission.1. +

2. Decay of carbon – 14 by beta emission

3. +

4. Decay of Thorium - 232 by an electron capture

5. +

Po21884

He42 Pb214

82

C146 0

1 N147

Th23290 0

1 Ac23289

Semester I Review

1. The half-life of phosphorous-30 is 2.5 min. If you start with 55 g of phosphorus-30, how many grams would remain after 27.5 min?

Mfinal = (55g)(.5)11 = 0.027g

Semester I Review A radioactive isotope decayed from 200.0

grams to 3.125 grams in 15 years. Determine the half-life of the isotope.

3.125g = 200.0(0.5)X

64 = 2X

X = 6, so 6 half-lives have passed in 15 years. Therefore each half-life is 2.5 years long

Semester I Review

Calculate the wavelength of electromagnetic radiation with a frequency of 6.5x1016 Hz.

4.6x10-9 m Calculate the energy of the above

electromagnetic radiation.

4.3x10-17 J

Semester I Review

If n=4; how many sublevels 4, Orbitals 16, and Electrons are present 32?

T or F (p) sublevels have 7 orbitals T or F (d) sublevels hold only 6 electrons T or F (s) sublevels hold 2 electrons

Semester I Review For the element Cobalt; give the: Long hand electron configuration1s2 2s2 2p6 3s2 3p6 4s2 3d7

Box and arrow notation

Noble gas configuration[Ar] 4s2 3d7

Electron Dot Structure

Semester I Review Give the ion for each of the following

elements: Sodium, Oxygen, Chlorine, Barium,

Gallium, Sulfur, Nitrogen, Aluminum, Silver, Zinc, Cadmium

Give the formula for the following compounds 1) iron (II) arsenide Fe3As2

2) lead (II) sulfate PbSO4

3) lead (IV) hydroxide Pb(OH)4

4) copper (II) acetate Cu(C2H3O2)2

5) beryllium chloride BeCl2 6) ammonium chromate (NH4)2CrO4

7) silver oxide Ag2O

8) potassium sulfide K2S

Semester I Review

Give the name of the following compounds 1) NaBr Sodium Bromide 2) Sc(OH)3 Scandium (III) Hydroxide 3) V2(SO4)3 Vanadium (III) Sulfate 4) NH4F Ammonium Fluoride 5) CaCO3 Calcium Carbonate 6) NiPO4 Nickel (III) Phosphate 7) Li2SO3 Lithium Sulfite 8) Zn3P2 Zinc Phosphide 9) Sr(C2H3O2)2 Strontium Acetate 10) Cu2O Copper (I) Oxide

Semester I Review