<span>First we can calculate the area of the rectangular lawn using the formula:
Area = Width x Length = 21 ft x 20 ft = 420 square feet
And the total number of snow flakes per minute on the entire lawn is:
(1350 snowflakes per minute per square foot) x (420 square feet) = 567,000 snowflakes per minute
In one hour (or 60 minutes) we get a total of:
(567,000 snowflakes per minute) x (60 minutes / 1 hour) = 34,020,000 snowflakes
The total mass of which would be:
34,020,000 snowflakes x 1.60 mg = 54,432,000 mg = 54.432 kg (as 1 kg = 1,000,000 mg).
So 54.432 kg of snow accumulates every hour on the lawn.</span>
Answer:
B. A chemist
<em>Hope it's help :)</em>
The molality is 0.54 M when 1.34 moles of NaCl is present in 2.47 kg of solvent.
<u>Explanation:</u>
Molality is the measure of how much of amount of solute is dissolved in the solvent. So it is calculated as the ratio of moles of solute to the grams of solvent.

As in this case, the solute is NaCl and solvent is unknown. So the moles of solute is given as 1.34 moles and the mass of solvent is given as 2.47 kg.
Hence, 
Thus, the molality is 0.54 M when 1.34 moles of NaCl is present in 2.47 kg of solvent.
Answer:
Fe₃Si₇
Explanation:
In order to determine the empirical formula, we have to follow a series of steps.
Step 1: Determine the percent composition
Fe: 46.01%
Si: 53.99%
Step 2: Divide each percentage by the atomic mass of the element
Fe: 46.01/55.85 = 0.8238
Si: 53.99/28.09 = 1.922
Step 3: Divide all the numbers by the smallest one
Fe: 0.8238/0.8238 = 1
Si: 1.922/0.8238 = 2.33
Step 4: Multiply by numbers that make the coefficients whole.
Fe: 1 × 3 = 3
Si: 2.33 × 3 = 7
The empirical formula is Fe₃Si₇.