Answer:
Humans started to use pesticides dating back to before 2000 BC.
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Explanation:
Explanation:
5 I don't know what is the answer if I got it wrong
Answer:
2.94 x 
Explanation:
First we need to find out how many moles of ammonia there are, using the formula: Mass = mr x moles.
We know the mass is 83.1g, now we need to find the mR of ammonia - NH3.
N = 14, H = 1, so 14 + (3x1) = an mr of 17.
Moles = mass/ mr = 83.1/17 = 4.8882
Now we can multiply the moles by avogadro's constant to find the number of molecules:
4.8882 x (6.02 x 
) = 2.94 x molecules of ammonia
If 5.0 grams of KCl is dissolved in 500 ml of water, the concentration of the resulting solution will be 0.134M.
<h3>How to calculate concentration?</h3>
The concentration of a solution can be calculated by using the following formula;
Molarity = no of moles ÷ volume
According to this question, 5.0 grams of KCl is dissolved in 500 ml of water. The concentration is calculated as follows:
no of moles of KCl = 5g ÷ 74.5g/mol = 0.067mol
Molarity = 0.067mol ÷ 0.5L = 0.134M
Therefore, if 5.0 grams of KCl is dissolved in 500 ml of water, the concentration of the resulting solution will be 0.134M.
Learn more about concentration at: brainly.com/question/10725862
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