Practice Test for 6.1-6.3 1. Complete the following molarity calculations: a. What is the molarity of a solution containing 25.3 grams of copper (II) chloride dissolved in 140 mL of water? b. How many grams of sodium hydroxide are needed to make 2 L of a 0.05 M solution?
4 Calculate the molar mass of these compounds: (relative atomic masses: H = 1; N = 14; O = 16; S = 32; Cu = 64; Br = 80; Pb = 207) (a) copper nitrate, Ca(NO3)2 (b) lead bromate, Pb(BrO3)2 (c) ammonium sulfate, (NH4)2SO4 5 The equation for the complete combustion of methane is shown below. CH4 + 2O2 → CO2 + 2H2O When 80 g of methane is completely combusted, 220 g of carbon dioxide and 180 g of water are formed. (a) Why is the mass of carbon dioxide formed greater than the mass of methane burnt? (b) Calculate the mass of oxygen that reacted. (c) Calculate the mass of water formed when 20 g of methane undergoes complete combustion.
First, we had to calculate how many grams of copper (II) sulfate we needed to form 100 mL of a 0.200 M solution of copper (II) sulfate. We determined that we needed to use 4.994g of copper (II) sulfate to make the solution. We added distilled water to the 4.994g of copper (II) sulfate in a beaker until it reached 100 mL. Then we put the beaker on a hot plate and added a magnetic stirrer. We determined that the mass of zinc necessary to completely react with the copper (II) ions in the solution was 1.308g.
- 1 Spectrophotometer. Method to obtain solutions: - Weigh 0.25g of Cu powder in a beaker. - Under fuming cupboard add 1 cm^3 of Nitric Acid in the same beaker. - Pour the Copper Nitrate solution into the 250 cm^3 volumetric flask and dilute it with water until it reaches the line. - Using a pipette pour 5cc, 10cc, 15cc and 20cc of the solution into different volumetric flasks each of 100 cm^3 volume and dilute them until the line mark and
Siddharth Rajendran Chemistry HL Urea Dissolution Lab Raw Data:- (Expected Values) Change in Enthalpy: 14 kJ mol-1 Change in Gibbs free energy: 6.86 kJ mol-1 Change in Entropy: 69.5 J mol-1 Molar Mass of Urea: 60.06 g mol-1 Heat Capacity: 4.184 J g-1º Data Table 1: To calculate the Enthalpy change Mass of Urea Tablet (g) (±0.01g) | Volume of Water(mL) (±0.05mL) | Initial Temperature (Cº) (±0.2 Cº) | Final Temperature(Cº) (±0.2 Cº) | 3.04 | 50.0 | 21.3 | 17.4 | Initial Observations:- * There was a decrease in temperature at a fast rate. * The temperature of the solution was slowing down continuously but the rate started decreasing. * The Urea dissolved and the rate was decreasing continuously. * The temperature gradually started to increase after almost the Urea present had dissolved. Data Table 2: Mass, Volume and Temperature during Dissolution of Urea (To calculate Keq) Mass of Urea(g) (±0.01g) | Initial Temperature(Cº) (±0.2 Cº) | Final TemperatureCº) (±0.2 Cº) | Initial Volume(mL)(±0.05 mL) | Final Volume(mL)(±0.05 mL) | 3.76 | 21.4 | 22.9 | 5.02 | 7.14 | Processing Raw Data * Determining the Final temperature of dissolution of Urea in the Styrofoam cup.
What volume of concentrated (18.0 M) sulfuric acid would be required to make each of the following? a. 1.25 L of 6.00 M solution Mconc x Vconc = Mdil x Vdil (18.0 M) x (Vconc) = (6.00 M) x (1.25 L) Vconc=0.417 L b. 575 mL of 0.100 M solution Mconc x Vconc = Mdil x Vdil (18.0 M) x (Vconc) = (0.100 M) x (0.575 L) Vconc=0.00319 L Acid-Base Titrations 5. Calculate the molarity of an HCl solution if 20.0 mL of it requires 33.2 mL of 0.150 M NaOH for neutralization.
6.02 x 1023 atoms C. 6.02 x 1023 ions B. 6.02 x 1023 grams D. 6.02 x 1023 molecules 5. What ts the correct unit of a formula weight? A. gram B mol C. gram/mol D. mole/gram 6. How many individual atoms are there in 250 grams of O2?
1. Calculate the average atomic mass of silver using the following data: |Isotope |Abundance |Mass | |107Ag |51.84% |106.9051amu | |109Ag |48.16% |108.9048amu | |106.91 amu • 107.87 amu • 108.00 amu • 108.90 amu What is the average mass of one S atom? • 32.07 g • 32.07 amu • 32.07 g/mol • 32.07 mol What is the mass of 3.50 x 1024 Ti atoms? • 47.9 amu • 47.9 g • 5.81 g • 278 g How many C atoms are in 5.50 g of C? • 5.01 x 1022 C atoms • 2.76 x 1023 C atoms • 3.31 x 1024 C atoms • 5.50 x 1023 C atoms How many Cl atoms are in 0.0728 g of PCl3?
Create reactions with anion placeholders for copper compound and Zinc. If the copper is cuprous, or Cu+1, the reaction is: 2Cu+1(A-1) (aq)+ Zn+2(s) Zn+2(A-1)2 (aq)+ 2Cu+1(s) (A= anion) If the copper is cupric, or Cu+2, the reaction is: Cu+2(A-1)2 (aq) + Zn+2(s) Zn+2(A-1)2 (aq) + Cu+2(s) Calculate the grams of Zinc needed for the reaction if copper compound is cuprous (+1) or cupric (+2). If the Copper is Cuprous: 2Cu+1(A-1) (aq) + Zn+2 (s) Zn+2(A-1)2 (aq) + 2Cu+1(s) Grams of Zn = 1 gram of Cu(A) The amount of Cu(A) that will be used. 1 mol of Cu(A) Divided by the molar mass of Cu(A) 170.49 grams of Cu(A) as given by the instructor. 1 mol of Zn Multiplied by the mole ratio of Zn to Cu(A) 2 mol of Cu(A) in the reaction.
1. A solution containing 1.000M acetic acid (CH3COOH) and 1.000M ethyl alcohol (CH3CH2OH) at 150oC produced 0.171 mole/liter of the product ethyl acetate (CH3COOCH2CH3) when equilibrium was established. Determine Kc for the reaction. CH3COOH (aq) + CH3CH2OH (aq) CH3COOCH2CH3 (aq) + H2O (l) 2. Using the equilibrium constant from above, calculate the equilibrium concentrations of all the compounds in the reaction if 1.000M acetic acid is reacted with 2.000M ethyl alcohol.