Chemistry L3 Midterm Exam Review Problems 1. Physical or chemical change? a. Iron rusting b. Paper burning c. Crumpling paper 2. Convert 150km to m 3. Convert 1.56x105cm to km 4. Convert 654214dg to ng 5. Convert 45 mi/hr to m/s 6. Convert 678 mL/s to L/hr 7. Mrs. Neuman walks/runs on a semi-regular basis. She walks/runs for 45 minutes 3 days a week. She averages out to moving 4.75 miles per hour. How many meters has Mrs. Neuman walked/ran after 12 weeks? (1.61 km = 1 mile) 8. Convert 35 °F to °C. 9. Convert 313K to °F. 10. Put the following numbers in scientific notation: a. 0.00135 b. 14569.34 11. Take the following numbers out of scientific notation a. 3.45 x 103 b. 7.89 x 10-5 c. 6.23 x 100 12. How many sig figs are in the following numbers: a. 5005 b. 600. c. 50 d. 3.40 x 105 e. 0.7521 f. 0.009140 13. Round the following numbers to 4 sig figs: a. 16995 b. 87.297 c. 40001 14. What is the formula for density? a. What is the unit for mass? b. What is the unit for volume? c. What are the units for density? 15. What does a cubic centimeter equal? 16. Find the density of a block of wood with a mass of 25.00 g and a volume of 80.000 cm3 17. An irregularly shaped stone was lowered into a graduated cylinder holding a volume of water equal to 2 ml. The height of the water rose to 7 ml. If the mass of the stone was 25 g, what was its density? 18. What is the voume of a sample of a metal that has a mass of 0.40g and a density of 11.7g/mL? 19. Mrs. Stabile is terrible a darts. All of her darts hit the wall outside of the dartboard in a small cluster. a. Is Mrs. Stabile accurate when she plays darts? b. Is Mrs. Stabile precise when she plays darts? 20. In lab, you find the density of an object to be 5.16 g/mL. The actual density is 4.75 g/mL. What is your percent error? 21. What is important about the BrInClHOF elements? 22. What are isotopes? 23. Naturally occurring magnesium has three isotopes: Isotope Abundance Mass 24Mg 78.99% 23.985amu Chemistry L3 Midterm Exam Review Problems 25Mg 10.00% 24.986amu 26Mg 11.01% 25.983amu
What is the average atomic mass of magnesium? Show all work, sig figs, and units!!
24. Fill-in the chart: Symbol 133Cs 55 Protons Neutrons Electrons Atomic Number Mass Number Average Atomic Mass 25. Name the following compounds: a. HCl
b. MgCl2
c. PCl5
d. HBrO3
e. HClO2 26. Balance the following ionic compounds (criss-cross method) a. Lithium sulfide b. Calcium bromide c. Cuprous chloride 27. Name the type of reaction:
a. C10H8 + 12 O2 ---> 10 CO2 + 4 H2O
b. 8 Fe + S8 ---> 8 FeS
c. Mg(s) + 2 HCl(aq) → MgCl2(aq) + H2(g)
d. 2 H2O ---> 2 H2 + O2
e. Pb(NO3)2 + 2 KI ---> PbI2 + 2 KNO3 28. Balance the following reactions:
a. HgO Hg + O2
b. Al + Pb(NO3)2 Al(NO3)3 + Pb 29. Predict the products of the following reactions:
a. Ca(BrO3)2 + Na
b. F2 + MgCl2
c. CdBr2 + I2 30. Use your solubility rules to predict the products and balance the equations.
a. Na2CO3 + Ca(NO3)2
b. NaOH + CaCO3
31. Redox: Sb + H2SO4 Sb2(SO4)3 + SO2 + H2O a. Who is oxidized? b. Who is reduced? c. Who is the oxidizing agent? d. Who is the reducing agent?
32. What is the molecular weight of Ca3(PO4)2?
33. How many moles are in 562.40g NaHCO3? 34. How many molecules are in 2.74 moles NaCl? 24 35. How many grams are in 7.09 x 10 molecules of ZnCl2?
36. Determine the percent composition of CaCl2. Chemistry L3 Midterm Exam Review Problems 37. A chemist combines 1.26g iron with 0.56g oxygen to form rust. What is the percent composition of this new compound?
38. Cerium (III) iodide (CeI3) occurs as a hydrate with the composition 76.3% CeI3 and 23.7% H2O. Calculate the formula of the hydrate. Name the hydrate.
39. A 17.44g sample of a hydrate of zinc sulfate (ZnSO4) is heated strongly in a crucible to drive off all water of hydration. After heating, the sample has a mass of 9.79g. Calculate the molecular formula for this hydrate. Name the hydrate. 40.What’s the empirical formula of a molecule containing 65.5% carbon, 5.5% hydrogen, and 29.0% oxygen? 41. If the molar mass of the compound in problem #40 is 110 grams/mole, what’s the molecular formula?