Answer:
The answer is: <u>Al2O3</u>
Explanation:
The data they give us is:
To find the empirical formula without knowing the grams of the compound, we find it per mole:
- 0.545 g Al * 1 mol Al / 27 g Al = 0.02 mol Al
- 0.485 g O * 1 mol O / 16 g O = 0.03 mol O
Then we must divide the results obtained by the lowest result, which in this case is 0.02:
- 0.02 mol Al / 0.02 = 1 Al
- 0.03 mol O / 0.02 = 1.5 O
Since both numbers have to give an integer, multiply by 2 until both remain integers:
Now the answer is given correctly:
The number of molecules decrease
Answer:
[Au] = 0.171 M
Explanation:
For this question, we assume the rock is 100 % gold.
First of all, we determine the moles of gold
67.3 g . 1mol/ 196.97g = 0.342 moles
Molar concentration is defined as the moles of solute, contained in 1L of solution.
Our solution volume is 2L.
M = 0.342 mol / 2L = 0.171
Molar concentration, also called molarity of solution is the most typical unit of concentration.
Answer: C
Explanation: Pesticides protect our crops, but some studies show that they cause consumers to gain weight:)
There are 115 known elements as of today (Feb. 13, 2016)
so, 'C' is the correct answer
