vinager analyzing lab 1) A solid sample contains both NaOH and NaCl. 0.500 g of

Question

vinager analyzing lab

1) A solid sample contains both NaOH and NaCl. 0.500 g of this solid sample was dissolved in water to make a 20.0 mL solution and then this solution was titrated by 0.500 mol/L HCl solution. If 23 mL of HCl was used to reach the end point, what is the mass % of NaOH in the original solid sample?

NaOH + HCl --> NaCl + H2O

2)Instead of using 10 mL vinegar, a student used 15 mL vinegar for all his titrations. How will this affect the experimental result of Vinegar Analysis lab?

3) A pressure gauge was used to measure the air pressure inside a tire. If the pressure gauge reads 26 psi, what is the real pressure in psi of air inside this tire? Assume atmospheric pressure is 15 psi.

4) At constant pressure, density of gas is inversely proportional to its temperature. This is how hot air balloon is floating in air: burning fuel makes inside air temperature higher and density lower; low density air balloon float on high density regular air. What is the density of air in g/L at 55 degree C if the atmospheric pressure is 1.0 atm? The average molar mass of air is about 29 g/mol. Keep two decimal places for your answer.

5) At STP, 0.106 g of a gas sample occupies a volume of 51.3 mL. What is the molar mass of this gas? Keep 3 sig figs for your final answer.

6) Butane gas was collected in a graduated cylinder over water in Gas Laws lab. If the water vapor pressure at the given temperature is 2.2 kPa and the atmospheric pressure is 100.9 kPa, what is the pressure of butane in kPa inside the graduated cylinder? Keep one decimal place for your final answer.

7) Use solubility rules from your textbook and/or lecture slides to answer the following question:

Strong bases are metal hydroxides that are soluble in water. Which of the following is a strong base?

8) Spectator ions are ions from initial reactants that did not participate in net-ionic equation. For reaction between Fe and H2SO4 (see lab manual for reaction equations), what is the spectator ion?

9) Check all categories of weak electrolyte.

10) Acid rain may damage statues partially due to the following reaction:

2 H+ + CaCO3 --> Ca2+ + CO2 + H2O

What is the primary driving force of the reaction?

11) Idea of single displacement reaction:

1. Stronger metal can displace weak metal or hydrogen out of their compound.

2. Stronger halogen can displace weaker halogen out of their compound.

Which halogen element is the strongest?

12) Acid anhydride are nonmetal oxides that are resulted from oxyacid molecules losing water. For example, losing one molecule of H2O from H2SO4 produces its acid anhydride SO3. Acid anhydride can also combine with water to form the corresponding acids: SO3 + H2O --> H2SO4. This is why sulfur oxides, such as SO2 and SO3, are major sources of acid rain.

CO2, a component of air, is an acid anhydride of carbonic acid (H2CO3).

Given above knowledge, which one is correct about a sample of pure water after it is exposed to air for a while? Assume the air quality is excellent and there is no pollutant in air.

Explanation / Answer

1-NaOH + HCl --> NaCl + H2O

mole of HCl used= 23x10^-3 x 0.5 =11. 5 x10^-3

mole of HCl = mole of NaOH= 11.5x10^-3mole =0.460g

mw of NaOH=40g/mol

% mass of NaOH = 92%

2-It will make the mass % concentration of acetic acid in vinegar artifially higher.

5- At STP, 0.106 g of a gas sample occupies a volume of 51.3 mL.

at STP 1mole of gas occupies 22.4l

51.3 x10^-3L ...........wt =0.106g

22.4L ................wt = 0.106x22.4/51.3x10^-3 = 46.285g = molar mass

7- alkali & alkaline earth metal hydroxide are strong base so,

ans-Ba(OH)2

6-Ptotal = Pwater + Pgas

The pressure inside the container is the same as that outside

100.9 = 2.2 + P butane

Pbutane = 100.9- 2.2 = 98.7KPa

8- H+

9-weak electrolyte not completely dissociate in solution

weak acid, weak base

10-Nutralisation

11-F2

12-The water will be perfectly neutral (or pH = 7).

3-Absolute pressure = Gauge pressure + Atmospheric pressure= 26 +15 = 41psi

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