Question 3 (2010)
A sample of the insecticide dichlorodiphenyltrichloroethane (DDT), C14H9Cl5, was found to contain 0.120 g of carbon. What mass of chlorine was present in the sample?
A. 0.127 g
B. 0.355 g
C. 0.994 g
D. 1.01 g
Question 10 (2009)
The level of carbon dioxide in the air in a spacecraft can be controlled by passing the air through canisters containing lithium hydroxide, LiOH. In a laboratory trial, the air in a 5.00 L container at 1.10 × 102 kPa and 25.0°C was passed through a canister of LiOH. The pressure of the air in the container decreased to 1.00 × 102 kPa, measured at 25.0°C. The mass of CO2 absorbed from the air sample by the LiOH in the canister was A. 0.89 g
B. 9.77 g
C. 10.6 g
Question 3 (2008)
Xylose is a compound that has five carbon atoms in each molecule and contains 40% carbon by mass. What is the molar mass of xylose? A. 30
D. It cannot be determined without further information.
Question 3 (2009)
A student is to accurately determine the concentration of a solution of sodium hydrogencarbonate in a titration against a standard solution of hydrochloric acid, HC1. The first step in this experiment is to accurately dilute 100.0 mL of a 1.00 M HCl stock solution to a 0.100 M solution using a 1.00 L volumetric flask. However, instead of using distilled water in the dilution, the student mistakenly adds 900.0 mL of 0.0222 M sodium hydroxide, NaOH, solution. a.Write an equation for the reaction that occurs in the 1.00 L volumetric flask. 1 mark b.Calculate the concentration of the hydrochloric acid in the 1.00 L volumetric flask after the student added the sodium hydroxide solution. Give your answer to correct significant figures. 2 marks The student then uses this contaminated hydrochloric acid solution to determine the accurate concentration of the unknown sodium hydrogencarbonate solution. c.Will the calculated concentration of sodium...