B is the answer. hope this helps
Answer:
- second choice:<em><u> 1.0 g of the solution contains 15 × 10⁻⁶ g of benzene.</u></em>
Explanation:
ppm is a unit of concentration that means parts per million. In grams that is grams of solute per one million (10⁶) grams of solution.
Then, <em>15 ppm of benzene</em> means that there are 15 grams of benzen in 1,000,000 grams of solution.
That leads to:
- 1,000,000 g solution / 15 g benzene
Multiplying numerator and denominator by 10⁻⁶ you find:
- 1,000,000 × 10⁻⁶ g solution / (15 × 10⁻⁶ g benzene)
Simplifying:
- 1.0 g solution / (15 × 10⁻⁶ g benzene)
Which is read as 1.0 g of the solution contains 15 × 10⁻⁶ g of benzene, i.e. the second answer choice.
I'm not sure how to write this but the size shrinking could be due to erosion
Answer:
Li3PO4 - correct
FePO4 - correct
Cu3PO4 - correct
Mg3(PO4)2 - correct
Explanation:
In order to answer this question we must be conversant with the idea of valency as well as the idea of writing formula of ionic substances.
Lithium has a valency of 1 while PO4^3- has a valency of 3 so the correct formula of lithium phosphate must be Li3PO4 after the exchange of valencies.
Iron III has a valency of 3 while the phosphate ion also has a valency of 3 so the subscripts cancel out and iron III phosphate is FePO4.
Copper I ion has a valency of 1 and the phosphate ion has a valency of 3. When they exchange valencies, the formula of the compound is Cu3PO4.
Magnesium has a valency of 2 while the phosphate ion has a valency of 3. The exchange of valency gives us the formula Mg3(PO4)2.
