A solution is prepared by dissolving 49.3g of NaCl in enough water to form 438mL of solution. Calculate the mass% of sodium chloride in the solution if the density of the solution is 1.06 g/mL

• 10.6% NaCl

• 11.3% NaCl

• 9.6% NaCl

• 12.7% NaCl

• 10.1% NaCl

Suppose you have three beakers, labeled I-III, containing the following solutions:

I.) CuI₂(aq)

II.) KC₂H₃O₂(aq)

III.) CaSO₄(aq)

If a solution of lead(II) nitrate, Pb(NO₃)₂, is added to each beaker, in which will a precipitate form?

• Only beaker (II) will contain a precipitate

• All three beakers will contain precipitates

• Only beaker (I) will contain a precipitate

• Only beaker (III) will contain a precipitate

• Beakers (I) and (III) will contain precipitates

How many grams of sodium azide, NaN₃ (molar mass = 65.02g/mol) are needed to react by the equation below in order to inflate a 66.0L air bag with N₂(g) at 294K and 0.989atm pressure?

2NaN₃(s) --> 2Na(s) + 3N₂(g)

• 95.1g

• 44.2g

• 117g

• 60.1g

• 176g

How many molecules of gas are present in a 0.500L container of N₂ at 25.0°C and 760. mmHg of pressure?

• 9.36 x 10²⁴ molecules

• 1.23 x 10²² molecules

• 1.23 x 10²³ molecules

• 7.55 x 10²¹ molecules

• 6.02 x 10²³ molecules

What is the molarity of a HCl solution, if 15.78mL of the acid is needed to completely neutralize 10.00mL of a 0.2000M NaOH solution?

hint: think dilution

• 0.03156M HCl

• 31.56M HCl

• 7.890M HCl

• 0.3156M HCl

• 0.1267M HCl

An excess of nitric acid is added to 2.50g of copper metal.

Cu(s) + 4HNO₃(aq) → Cu(NO₃)₂(aq) + 2NO₂(g) + 2H₂O(l)

What is the volume of NO₂ gas produced at a pressure of 1atm and temperature of 0°C (STP conditions)?

• 44.8L

• 0.881L

• 112L

• 1.76L

• 0.0787L

Potassium nitrate, KNO₃, is added to toothpaste at 5.00% by mass to treat tooth pain. How much potassium nitrate is contained in a 124g tube of toothpaste?

• 6.20g

• 130.g

• 4.24g

• 5.26g

• 118g

At a constant temperature and pressure, 4 balloons are each filled with a different gas. The mass of each gas is given below. Which balloon will have the largest volume?

• balloon A with 15g Kr

• balloon B with 15g O₂

• balloon C with 15g Ne

• balloon D with 15g F₂

• All of the balloons will have the same volume.

What mass of hydrogen fluoride gas is needed to react with 50.0mL of 0.027M thorium(IV) hydroxide, Th(OH)₄, according to the following equation?

Th(OH)₄(aq) + 4HF(g) → ThF₄(s) + 4H₂O(l)

• 6.8g of HF

• 0.0068g of HF

• 0.27g of HF

• 0.0054g of HF

• 0.11g of HF

What is the pressure of 3.20 mol of laughing gas, N₂O, in a 20.0L tank at 21°C?

• 0.276atm

• 3.20atm

• 4.47atm

• 3.86atm

• 1.45atm