Chemistry Answers

You want to create a 0.25 M Sodium Bicarbonate solution. You weigh 5.00 grams of Sodium Bicarbonate. How much water is needed?

1. A sample of gaseous uranium hexafluoride, UF6, is held at a temperature of 300 K and a pressure of 0.1 mbar. The collision diameter of UF6 is 0.40 nm. (i) Calculate the root-mean-square (r.m.s.) speed of the molecules. Make sure to show all units in your working and how the units cancel out. [5 marks] (ii) Estimate the mean free path and collision frequency under these conditions. [10 marks]

Rank the following compounds from weakest to strongest intermolecular forces. Justify your answer.

1. a. H₂S b. I₂ c. N₂ d. H₂O

2. a. H₂Se b. H₂S c. H₂Po d. H₂Te

7.36 x 1024 free oxygen atoms     

Number of carbon atoms in 2.5g of HC2H3O2

Suppose that you are travelling in the Space Shuttle Endeavor on a journey to Mars. The atmosphere (of the vehicle) consists of 20% oxygen and 80% helium by volume. It was noticed before take off from the Kennedy Space Center that there is a small leakage which if unchecked, would lead to a continual loss of gas at a rate of 0.05 atm/day through effusion. If the temperature in the space shuttle is maintained at 22°C and the volume of the vehicle is 15,000 liters. Calculate the amounts of helium and oxygen in grams that must be stored on a 5-day journey to allow for the leakage.

Calculate the volume of a given mass of gas at 760mmhg when its volume was increased by 10dm3 st 710 mmHg of the gas

In a particular experiment, 50 drops of HCl solution were dispensed from a burette, and the final and initial readings of the burette were 45.03 mL and 15.03 mL respectively. What was the volume of each drop?

Recall that the length of the box is a substitute measure for the box’s volume. Plot a graph of your results from part A.

When 47.4 g of KClO3  is completely decomposed, what is the theoretical yield, in grams, of O2 ?