The chloroform contamination level in water is 15 ppm (by mass of chloroform). Calculate the molality of chloroform in this water sample, which represents the number of moles of chloroform dissolved per kilogram of pure water solvent:

1.	3.25 × 10-4	2.	1.5 × 10-3
3.	7.5 × 10-3	4.	1.25 × 10-4

For the reaction:
A + B₂ → AB₂
Which of the following cases represent situations in which A acts as the limiting reagent?

 
Choose the correct option:

If 10 volumes of H₂ react completely with 5 volumes of O₂, what volume of water vapor will be produced under the same conditions of temperature and pressure?

1. Nine (9)

2. Eight (8)

3. Ten (10)

4. Eleven (11)

Find the value of 15.15 pm expressed in the basic SI unit of length.

1. 1.515 × 10^–12 m

2. 2.57 × 10^–11 m

3. 2.87 × 10^–11 m

4. 1.515 × 10^–11 m

Determine the number of significant figures that should be present in the final answers for each of the following expressions:

The molar mass of naturally occurring Argon isotopes is: 

Find the mass of CaCO₃ required to completely react with 25 mL of 0.75 M HCl according to the reaction:

CaCO₃(s) + 2HCl(aq) → CaCl₂(aq) + CO₂(g) + H₂O(l)

1. 0.36 g

2. 0.09 g

3. 0.96 g

4. 0.66 g

How many grams of HCl are required to react with 5.0 g of manganese dioxide in the reaction provided?
\(4 \mathrm{HCl}_{(\mathrm{aq})}+\mathrm{MnO}_{2(\mathrm{~s})} \rightarrow 2 \mathrm{H}_2 \mathrm{O}_{(\mathrm{l})}+\mathrm{MnCl}_{2(\mathrm{aq})}+\mathrm{Cl}_{2(\mathrm{~g})}\)

1. 4.8 g

2. 6.4 g

3. 2.8 g

4. 8.4 g

Which of the following correctly represents 234,000 and 6.0012 in scientific notation?