Gen Chem Exam 1 Review

Math

100

How many sig figs does 0.00030 have? 

2

200

Convert 529 C to K

K= C + 273.15 

K= 529 C + 273.15 = 802.15 K = 802 K

300

[60.891+78.90]/ 14.906 X 0.45 = 

2.0 X 10²

400

Tell me the rules for significant figures. 

(+/-) round to least sig decimal place

(x & /) least # of sig figs 

All nonzero, 0's btw nonzeros, 0's at the end of decimal numbers, 0's in the coefficient of #'s written in significant notation,  #'s are significant 0

0's at the end of nondecimal and beginning of decimal #'s, are NOT significant

500

What is the # of moles of NaCl contained in 0.500 L of a 1.5 M solution? 

0.75 moles of NaCl

Conversion

100

mm stands for? 

millimeter

200

0.18 kg in grams

180 g 

300

If milligrams is 10^-3 then micrograms is? 

10^-6

400

Unit for microliter is? 

μl

500

10.3 picometers are how many nanometers and meters? 

0.0103 nanometers and 1.03 x 10^-11

Elements, CP, and Mixtures

100

What are the two kinds of pure substances? 

Elements and Compounds

200

Mixtures are classified as?

Homogenous and heterogeneous

300

Is lucky charms a pure substance or mixture? Is it an element, cp, homogenous, or heterogenous? 

Mixture & heterogenous 

400

Is food digestion a chemical or physical process? 

Chemical

500

What is the difference between an element and a compounds? Give examples. 

Element is made up of one atom and a compound is containing two or more elements 

Chapter 2

100

What is the formula for density and what are the units? 

D= m/ v ; g/mL or g/cm³

200

The element is? 28 and 19 refer to? 

²⁸₁₉ K

Potassium, 28 = Mass # ; 19 = Atomic #

300

Boron - 10. What does the number mean? 

 mass #

400

Name all 8 Metalloids. 

B, Si, Ge, As, Sb, Te, Po, At

500

What is the ionic formula that has a cp of Mg and O?

Mg₂O_{2 = MgO ; look at charges, Mg has 2+ and O has 2-}

Chapter 3

100

The __ is the sum of the atomic weights of the atoms in a molecule?

Molecular Mass. 

C₂H₆: C (2) (12.011) amu 

+.      H (6) (1.007) amu 

----------------------------------

            30.064 amu

200

What does Avogadro's # tell us?

That there are 6.022 x 10²³ objects in 1 mol 

300

What is the name for compounds FeCl₂?

Iron (II) Chloride

400

Percetage composition by mass of H in ethane (C2H6) is: 

% Element={ [# of atoms x atomic mass ] / mass of cp } 100 

[( 6 x 1.008 amu)/ 30.064 amu ] x 100 = 20.098%

500

A cp is composed of 52.14% C, 13.13% H, and 34.73% O by mass. What is the empirical formula? If the molar mass is 138.204 g/mol, what is the molecular formula? 

Empirical: C2H6O1

Molecular: C6H18O3