WHITE BOARD REVIEW HONORS CHEMISTRY

Question How many formula units are in 4 g AlCl3? 1.81 x 1022 formula units AlCl3

Question What’s the atomic mass of Fe? 55.85 g

Question A 45 g metal at 98°C is dropped into 64 g of water at 23°C. The final temperature of the system is 54°C. What’s the specific heat of the metal? 4.19 J/g°C

Question Determine the ∆H of NO + ½O2  NO2 given: ½N2 + ½O2  NO 90.29 kJ ½N2 + O2  NO2 33.2 kJ -57.1 kJ

Question Using: 4NH3 + 5O2  4NO + 6H2O, determine how many grams of H2O are formed from 100 grams NH3 and 100 grams of O2? Which reactant is limiting? Which is in excess? 67.58 g H2O Limiting: O2 Excess: NH3

Question The pressure of a sample of He in a 2.0 L container is 2.50 atm, at constant temp. What’s the new pressure if the sample is placed in a 4.0 L container? 1.25 atm

Question How many moles were dissolved in 400 g of water to make a 6.4 m solution? 2.56 moles

Question How many grams of solute are in 4500 g of a 40,000 ppm solution? 180 g

Question How much energy (in kJ) is released when condensing 62 g of water? -140.12 kJ

Question How many grams are in 4 mol AlCl3? 533.32 g AlCl3

Question How many kg of NaCl are dissolved in 4.9 kg of water to make a 5.0 m solution? 1.43 kg NaCl

Question How many formula units are in 4 mol AlCl3? 2.4 x 1024 formula units AlCl3

Question What’s the percent of Calcium in CaCO3? 40%

Question What’s the empirical formula of a compound where 36.2% is Al and 63.8% is S? Al2S3

Question Determine the Keq and favorability of the reaction: H2(g) + I2(g) ↔ 2HI(g) with equilibrium concentrations of: 3.56 M H2, 1.25 M I2 and 15.59 M HI Keq = 54.62 Products favored

Question How much energy does 26 g of steam at 112°C release to turn to ice at -5°C? -79,213.42 J

Question A sample contains 66.66% C, 3.74% H and 9.60% O. The formula mass of the sample is 216 g/mol. What’s the molecular formula of the sample? C12H8O4

Question What is the volume of air in a balloon that occupies 0.62 L at 25°C, at constant pressure, if the temp is lowered to 0°C? 0.57 L

Question How many grams of an ideal gas sample of Ne are in a 4000 mL sample at 29.4 psi and 25°C? 6.60 g Ne

Question A 162.29 g sample of CuSO4•XH2O is heated. After the water is heated off, 103.74 g of the anhydrate remain. Determine the formula of the hydrate. CuSO4•5H2O

Question A sample of air at 1 atm, contains CO2, N2 and O2. If the PN2 is 593.525 torr and PCO2 is 0.285 torr, what’s PO2 (in torr)? 166.19 torr

Question Using: H2 (g) + Cl2 (g)  2HCl (g), at STP, how many liters of Cl2 are needed to make 44.8 g of HCl? 13.76 L Cl2

Question Using: H2 (g) + Cl2 (g)  2HCl (g), at STP, how many molecules of H2 are needed to make 44.8 L of HCl? 6.022 x 1023 molecules H2

Question What’s the molarity when 0.96 moles of solute are dissolved to make 4.8 L solution? 0.2 M

Question How many moles were dissolved to make 4.0 L of a 3.4 M solution? 13.60 moles

Question What’s the percent of oxygen in CaCO3? 48%

Question How many grams of NaCl are dissolved to make 0.5 L of a 3.0 M solution? 87.66 grams NaCl

Question What’s the molality when 0.96 moles of solute are dissolved in 2.5 kg water? 0.384 m

Question How many kPa are in 782 mmHg? 104.23 kPa

Question How many grams of water are boiled when absorbing 46,000 J of energy? 20.35 g

Question What’s the final temperature of 56 g of water at 21°C that releases 500 J? 18.87°C

Question What’s the concentration in ppm, when 56 g of KBr dissolve to make a 3500 g solution? 16,000 ppm

Question At STP a gas occupies 30.0 mL. If the temp is increased to 30°C and the new volume is 20 mL, what’s the new pressure? 1.66 atm

Question An ideal gas sample occupies 8.77 L at 20°C. What is the pressure, in atm, if there are 1.45 mol in the sample? 3.98 atm

Question How many grams of water release 400 J of energy when cooling from 45°C to 32°C? 7.35 g

Question How much energy does 56 g of ice at -15°C absorb to turn to water at 54°C? 33,061.62 J

Question H2 is collected over water at 20°C. The PH2 is 712.5 mmHg. What’s the atmospheric pressure? 730 mmHg

Question What’s the concentration in ppm, when 56 g of NaBr are dissolve in 4.5 kg of water? 12,291.48 ppm

Question A 3.0 M of a 320 mL solution is diluted to 500 mL. What’s the new concentration of the solution? 1.92 M

Question How many mL of water are added to 100 mL of a 3.5 M solution to create a 1.5 M solution? 133.33 mL

Question Determine the rate law & orders of the reaction 2A + 4B  3C using the data table: R = k[A][B]2 first order in A second order in B third order overall Trial [A] [B] Rate 1 1.2 1.4 3.3 2 2.4 6.6 3 2.8 13.2

Question How many mL of a 5.0 M solution are needed to make 40 mL of a 3.5 M solution? 28 mL

Question How many Calories are in 300 calories? 0.30 Cal

Question How many Joules are in 400 calories? 1,673.6 J

Question A gas at 660 torr and 22°C at constant volume is heated to 44.6°C, what’s the new pressure? 710.56 torr

Question How many Joules are in 160 Calories? 669,440 J

Question How many Calories are in 70 kJ? 16.73 Cal

Question How much energy is released when 40 g of water cools from 87°C to 23°C? -10,711.04 J

Question How much energy is absorbed when 20 g of water heats from 17°C to 53°C? 3,012.48 J

Question What’s the specific heat of an unknown metal with a mass of 4.25 g that absorbs 200 J of energy going from 53°C to 79°C? 1.81 J/g°C

Question Using: 4NH3 + 5O2  4NO + 6H2O, determine how many moles of NO are formed from 15 mole O2? 12 mol NO

Question Using: 4NH3 + 5O2  4NO + 6H2O, determine how many grams of H2O are formed from 10 mole O2? 216.24 g H2O

Question How much energy (in kJ) is absorbed when melting 52 g of water? 17.37 kJ

Question Using: H2 (g) + Cl2 (g)  2HCl (g), at STP, how many liters of Cl2 are needed to make 48 L of HCl? 24 L

Question Using: 4NH3 + 5O2  4NO + 6H2O, determine how many moles of H2O are formed from 100 grams O2? 3.75 mol H2O

Question Using: 4NH3 + 5O2  4NO + 6H2O, determine how many grams of H2O are formed from 200 grams NH3? 317.25 g H2O

Question Using: 4NH3 + 5O2  4NO + 6H2O, determine the percent yield when 45 g of NH3 produces 65 g NO in the lab? 82.02%

Question How many psi are in 1.45 atm? 21.32 psi

Question How many torr are in 1.45 atm? 1102 torr

Question How many mmHg are in 15.8 psi? 816.87 mmHg

Question What’s the molar mass of (NH4)2SO4? 132.17 g