Chemistry FALL semester review

2012-2013

1. Classify each of the following as a homogeneous or heterogeneous mixture:

a. slice of bread HOMOGENEOUS

b. a cup of coffeeHOMOGENEOUS

c. 14 kt. Gold HOMOGENEOUS

d. CarpetHETEROGENEOUS

2. Classify the following substances as pure or mixtures:

a. sugarpure

b. airmixture

c. cookiemixture

d. gasoline mixture

e. hand lotion mixture

3. Classify each of the following as a physical or chemical change:

a. spoiling cheese chemical b. dusting physicalc. rusting chemical d. Evaporating physicale. crushing physicalf. corrosion chemical g. cooking chemical h. Melting physical

4. Classify the following properties as either an intensive property and an extensive property.

a. 0.475 g extensive b. blue color intensive c. melting point intensived. Mass extensivee. weight extensivef. density intensiveg. odor intensiveh. Volume extensive

5. How has the periodic table developed?

(how does Medeleev’s table compare to Mosley’s)

• 1st table=Medeleev made and ordered elements by average atomic MASS

• Our table now=Mosley’s ordered elements by atomic NUMBER

6. In the element symbol Carbon-14, the number is the :

mass number.

7. An isotope has 15 protons, 16 neutrons, and 15 electrons.

– What is the atomic # of this isotope? • 15

– What is the identity of the isotope? • Phosphorus

– What is the mass # of this isotope?• 31

– What is the average atomic mass of all of the isotopes of this element?• 30.9793

8. What part of Dalton’s atomic theory was disproved by Thomson’s experiment?

• Dalton said atoms were solid spheres, like pool balls-indivisible….

• Thomson proved that there were charged particles that made up parts of the atom when he discovered the electron…

9-11. Name of Model:

Dalton : Billiard ball

Thomson: Plum Pudding

Rutherford : Nuclear

12-13. Subatomic Particle DiscoveredExperiment

Thomson: electron

Rutherford: proton

14. How many electrons are indicated by the following symbols?

– Mg2+ __lost 2 e-__ (magnesium gained or lost electrons). Now has 10 e-

– P3- __gained 3 e-__(Phosphorus gained or lost electrons) Now has 18 e-

15. What is the average atomic mass of Mg if 78.99% of Mg atoms are isotopes with a mass of 23.9850 amu, and 21.01% have a mass of

24.5 amu?

.7899 x 23.9850 = 18.95

.2101 x 24.5 = 5.15

Then : 18.95 + 5.15 = 24.1

16. Correctly order the following electromagnetic waves from most to least energy:

gamma ray, x-ray, microwave, UV, visible, infrared, radio

17. Which of the following has the largest wavelength /least energy? (Be able to

answer this type of question for any of the colors.)

– Green light or red light: Red– Purple light or yellow light: Yellow light

ROY G BIV(Longest wavelength/Lowest energy to shortest

wavelength/highest energy)

18. Which of the following has the largest frequency/ most energy? (Be able to answer this type of question for any of the colors.)

– Blue light or orange light: blue light– Green light of red light: green light

ROY G BIV(Longest wavelength to shortest)

19. How would you rearrange the following equation: c = f•λ to solve for

(hint…remember the triangle??)

F = C λ

λ = C f

20. What is c in this formula (always)?

Look at your “constants and conversions” on your formula chart!!!

The speed of light!

21. Perform the following calculations:

What is the wavelength of a wave with a frequency of 7.21 x 1014 s-1?c = λ (3.00 x 108 m)(s) = 0.000000416 m OR 416 nmf (s)(7.21 x 1014)

A wave has a wavelength of 3.21 x 10-6. What is its frequency?

• c = f (3.00 x 108 m) = 9.35 x 1013 Hz λ (s)(3.21 x 10-6m)

22. What is the energy of a photon of light with a frequency of 6.2 x 1014 Hz?

• E = hf h = 6.6262 x 10-34 J•s

• E = (6.6262 x 10-34 J•s) (6.2 x 1014) = 4.1 x 10-19JS

23. What are valance electrons?

The electrons on the outer most shell, they are available for bonding…

24. What is true about the valance electrons of all of the elements in a group on the periodic table?

They are equal to the group A number.

What element doesn’t follow the rule described above?– Helium…doesn’t have 8, has 2

25. How many valance electrons do each of the following elements have?

– Ca: 2– C: 4– F: 7– Li: 1

26. How many energy levels do each of the following elements have, which has

the largest atomic radius?

– Na: 3 – Ge: 4– He: 1– I: 5

27. As you move from left to right on the periodic table,

– What happens to radius? • Gets smaller

– What happens to ionization energy? • Gets larger

28. As you move from top to bottom on the periodic table,

– What happens to radius? • Gets larger

– What happens to ionization energy? • Gets smaller

29. Place the following elements in order from smallest to largest atomic radius

Br, Ca, K, Ga:

• Br, Ga, Ca, K

30. Label the groups of the periodic table31. Label the metals, metalloids, and nonmetals

32. What is the electron configuration for Calcium, atomic number 20?

• Longhand : 1s22s22p63s23p64s2

• Shorthand : [Ar]4s2

• Orbital Diagram :

33-36. Write the balanced equations for the following nuclear reactions and answer the questions:

Alpha decay (what is emitted): Helium is emited 4 252

2 101Beta Decay (what is emitted): electron is emitted 0 201 -1 80What is emitted in Gamma reactions?

ENERGY!!!

Lr256103

Au20179

He + Md

e + Hg

Alpha decay (emits helium):

Beta Decay (emits and electron):

37. Give the formulas for the following compounds:

– potassium sulfate = K2SO4

– ammonium phosphate= (NH4)3PO4

– iron (III) chlorite= Fe(ClO2)3

– strontium phosphate= Sr3(PO4)2

38.Give the names of the following compounds:

– Fe2CO3 = iron carbonate

– Na3PO4 = sodium phosphate

– Ca(ClO3)2 = calcium chlorate

– Al2O3 = aluminum oxide

39. Draw the Lewis structures and name the shapes of each compound:

– HBr

– BH3

– CCl4

40. Name the following compounds:

N2O3 = Dinitrogen trioxide

SBr2 = Sulfur dibromide

41. Write the formulas of the following compounds:

– Disulfur tetraflouride = S2F4

– Trinitrogen hexafluoride = N3F6

42. Law of conservation states that you cannot create atoms or destroy them, they are just rearranged during chemical reactions. Balance the following reactions:

2 KClO3 2 KCl + 3O2

1 K3PO4 + 3 HCl 3KCl + 1H3PO4

1 C3H8 + 5 O2 3 CO2 + 4H2O