Answer:
- <u><em>1.7 × 10³ kg of ore.</em></u>
Explanation:
Call X the amount of aluminum ore mined to produce 1.0 × 10³ kg the aluminum metal.
Then, taking into account the yield of the reaction (82 % = 0.82) and the percent of aluminun in the ore (71% = 0.71), you can write the following equation:
- X × 71% × 82% = 1.0 × 10³ kg
↑ ↑ ↑ ↑
(mass of ore) (% of Al in the ore) (yield) ( Al metal to obtain)
You must just simplify, solve and compute:
- X = 1,000 / (0.71 × 0.82) = 1,000 / 0.5822 = 1,717.6 Kg
Round to two significant figures; 1,700 kg = 1.7 × 10³ kg of ore ← answer.
Answer:
C
Explanation:
C) an atom with an atomic number of 18
Answer:
3:2, B
Explanation:
The mole ratio is simply the coefficients in a balanced chemical reaction and their relation to each other.
One simple way to easily know b is the correct answer is to look at the units for the answer choices. A is a ratio of Fe to Fe, C is a ratio of Mg to Fe, and d is a ratio of Mg to Fe. That alone must mean B is the correct answer.
We can also use the definition of a mole ratio, as stated above. Given that this equation is balanced, the mole ratio is simply the ratio of the coefficients, and is thus 3:2.