Chem 210 Fall 2009 Practice Exam #1 (HBA week 6 due 9/22/09)
1. Show all of your work and leave the answer in the correct number of significant figures.
2. Look through the entire exam and do the problem you feel most confident about first.
3. Put your name on the back of the information sheet and turn it in with your exam.
4. I agree to not discuss the details of this exam with anyone until the exam is returned. I understand that I will receive a zero on the exam if I cheat in any manner.
Signature __________________________________________________________
Question 1 Circle the correct choice T = true F = false
T F The value 0.0320 g has 3 significant figures.
T F 10 mm3 has the same volume as 1 cm3
T F A buret is more precise than a beaker.
T F Percent error is used to calculate the accuracy of an experiment.
T F C3H7OH is a condensed structural formula.
T F An anion has less electrons than protons.
T F Metals form cations in ionic compounds.
T F All compounds have a zero charge overall.
T F One mole of water has more molecules than one mole of hydrogen gas.
T F In our class the coefficients of the balanced equation have units of moles.
Question 2 Circle the correct choice from the ( ) to fill in the blank.
A) Water boils when heated. This is a ___________ (chemical, physical) change.
B) Carbonic acid breaks down into water and carbon dioxide. This is a ___________ (chemical, physical) change.
C) Ice floats on water. If you have 1 ml of each which one has the smaller mass?___________ (ice, water)
D) Atoms of the same element always have the same ______________(mass number, atomic number)
A) What is the molar mass of Fe2(SO3)3 ?
B) Write the atomic symbol for 19 protons, 21 neutrons and 18 electrons
C) Write the atomic symbol for 7 protons, 8 neutrons and 10 electrons
D) Sketch the periodic table as we did in lecture label the metals and the nonmetals.
E) What is the density of one metal bead if a sample of 100 metal beads weighs 27.134 grams and when the 100 metal beads are placed in a graduated cylinder the volume goes from 11.0 mL to 13.0 mL ?
F) A saline solution has a density of 1.149 g/ml. How many ml are required 23.36g?
G) What is the average and standard deviation for the following set of data points?
13.223 13.225 13.222 13.227 13.221
Write the formulas for the following.
Lead (II) arsenite _________________________
Mercury (I) fluoride ______________________
Aluminum sulfate trihydrate ________________
Iodine____________
Barium hydrogen carbonate ____________
Disulfur pentanitride _____________________
Name the following compounds.
CCl4 ______________________________
HBrO (aq)__________________________
CuNO3 ____________________________
KOH___________________________
NH4NO3 ________________________
Mn 5+ ____________________________
Question 5
A) A compound is composed of 39.1% C, 8.7% H and 52.2% O. Determine the empirical formula.
B) What is the molecular formula of a compound with a molar mass of 150 g/mol and the empirical formula is CH2O?
Question 6 Balance the following equations and state what type of reaction each is.
A) MgCl2 + Li3PO4 à
B) The decomposition of iron(III) oxide into its elements.
C) The formation of sodium dihydrogen phosphate from its elements.
D) The combustion of C5H11OH.
E) In + H2SO4 à
Question 7
A) How many grams of water (18.02 g/mol) are required to completely react with
300.0 grams of PCl3 ( 137.5 g/mol)?
PCl3 + 3 H2O à H3PO3 + 3 HCl
B) This reaction has an 85.3 % yield in HNO3. If 200.0g H2O2 (34.0 g/mol) reacts with excess N2H4, how many grams of HNO3 ( 63.0 g/mol) will be made?
7 H2O2 + N2H4 à 2 HNO3 + 8 H2O
C) K2O + H2O à 2 KOH
If you have 30.0 grams of each reactant in the reaction above answer the following.
(K2O 94.2 g/mol, H2O 18.0 g/mol, KOH 56.1 g/mol)
i) How many grams of KOH are produced?
ii) What is the limiting reagent?
iii) What is the excess reagent?