Question: salt water is an example of

a.Element

b.Substance

c.Homogeneous mixture *

d.Heterogeneous mixture

e.compound

Sheldon wants Leonard to honor room mate agreement section 8 subsection 2b by using precisely no more than 172.5 cm3 of space for his visiting non-human guest (density of guest=2.3 lb / 1.2 quarts). Choose the best equation to find out if Leonard’s 4.11 pound non human guest, can stay

a. 4.11 lb x 2.3 lb x 1.06 quart x 1 L x 1 mL = 7.9 x 10-3 cm-3

1.2 quart 1 L 1000 mL 1 cm3

Yes, non human guest is allowed. (units = lb2/cm3)

b. 4.11 lb x 1.2 quart x 1 L x 1000 mL x 1 cm3 = 2000 cm3

2.3 lb 1.06 quart 1 L 1 mL (2.0 x 103 cm3) No, non human guest is not allowed. * (correct answer)

c. 1.2 quart x 1L x 1000 mL x 1 cm3 = 490 cm3/lb 2.3 lb 1.06 quart 1 L 1 mL Yes, non human guest is allowed. (wrong unit for volume)

d. 1 x 2.3 lb x 1.06 quart x 1 L x 1 mL = 4.9 x 10-4 cm -3

4.11 lbs 1.2 quart 1 L 1000 mL 1 cm3

Yes, non human guest is allowed. (cm-3 not volume unit)

e. None are correct. Leonard will veto the room mate agreement & will accept non human guest into the apartment regardless.

For the following symbol 17O 8

a. 17 is the # of neutrons & protons

b. 8 is the number of protons

c. 17-8 = number of neutrons

d. Statements a and b are true.

e. a,b,c are true. *

Given the periodic table, choose the one incorrect statement.

a. Periods go horizontally across the table. Groups are vertical.

b. The alkaline earth metal elements are in group IA and the alkali metals start with Be and end with Ra. * (backwards IA alkali metal)

c. Noble gases consist of He to Rn and are very inert to chemical reaction.

d. Halogens consist of F,Cl,Br, I and At.

e. The chalcogens consist of group VIA.

38

For the element Sr 87.62

(this is what you see in periodic table)

a. The number of protons = 38 & the number of electrons = 38. The number of neutrons = 87.62 - 38

b. The element is in group IIA and has a charge of negative 2. (not true, +2)

c. Sr(NO3)2 is named strontium nitrate. d. Statements a and c are true. *e. Statements a,b are true.

Al (s) + HCl AlCl3 + H2

The coefficients are:

a. 1, 1, 1, 1

b. 2,3,1,2

c. 2,6,2,3*

d. 1,3,1,3

e. 1,3,1,1

The molecular weight of H2SO4 is:

a. MW=2(1.01) x 32.0 x 4(16.0)

b. MW= 1.01 + 32.0 + 16.0

c. MW = 2(1.01) + 32.0 + 4(16.0) *

d. MW= 2(1.01) + 16.0 + 4 (8.0)

Choose the one incorrect statement:a. 1 mole of the element Li has 6.02 x 1023 atoms

of Li and weighs 6.94 grams

b. 1 mole of Ca(OH)22 has 6.02 x 10 23 molecules of Ca(OH)2 and weighs [40.1+2(16.0+1.01)]= 74.12grams)

c. 1 mole of SF6 has 4 x (6.02 x 1023) atoms of F and has 4 x 19.0 = 76 grams of F (6)incorrect

d. 1 molecule of Ca(OH)2 weighs 74.12 amu

e. 1 mole of N2 has 2 x (6.02 x 1023) atoms of N and 6.02 x 10 23 molecules of N2

Choose the one best statement.

a. 1 mole has 6.02 x 10 23 atoms of an element.b. A mole weighs the same as the atomic mass

of the element in grams (ex: molar mass of Mg is 24.3 grams)

c. 1 mole of a molecule has 6.02 x 10 23

molecules. d. 1 mole weighs the same as the molecular

weight of the molecule in grams. (ex: molar mass of MgCl2 is [24.3 + 2(35.5)] grams)

e. All statements are correct. best statement

How many atoms of Cl is in 354.2 g of MgCl2

[FW (MgCl2) = 95.3 g] ?

a. 95.3 g MgCl2 x 354.2 g MgCl2 x 6.02 x 1023 atoms Cl

mol MgCl2 35.4 g Cl

b. 354.2 g MgCl2 x 1 mol MgCl2 x 2 mol Cl x 6.02x1023 atoms Cl

correct 95.3 g MgCl2 1 mol MgCl 2 1 mol Cl

c. 354.2 g MgCl2 x 95.3 g MgCl2 x 1 mol MgCl2 x 6.02x1023atomCl

1mol MgCl2 2 mol Cl 1 mol Cl

d. There is not enough information to answer this question – duh!

For the reaction 2H2 + O2 2H2O, if you start with 2.0 grams of O2 [MW (H2) = 2.02, MW (O2) = 32.0, MW (H2O) =18.02] (Choose the one best statement.)

a.grams(H2O)=2.0 g O2x 1mol O2 x 1 mol H2O x 18.02 g H2O

formed 32.0 g O2 1 mol O2 1 mol H2O

b.grams (H2)=2.0 gO2 x 1 mol O2 x 2 mol H2 x 2.02 g H2

(consumed) 18.02 g O2 1 mol O2 1 mol H2

c.moles (H2O)=2.0 g O2 x 1 mol O2 x 2 mol H2O correct

formed 32.0 g O2 1 mol O2

d. moles (H2)=2.0 g O2 x 1 mol O2 x 1 mol H2

(consumed) 32.0 g O2 1 mol O2

e. All statements are correct.