Answer:
0.136g
Explanation:
A student dissolved 5.00 g of Co(NO3)2 in enough water to make 100. mL of stock solution. He took 4.00 mL of the stock solution and then diluted it with water to give 275. mL of a final solution. How many grams of NO3- ion are there in the final solution?

Initial mole of Co(NO3)2 

Mole of Co(NO3)2 in final solution

Mole of NO3- in final solution = 2 x Mole of Co(NO3)2

Mass of NO3- in final solution is mole x Molar mass of NO3

When y equals 5, x is 104.3
When y equals 3 then x is 108.3
<em><u>Solution:</u></em>
<em><u>Given expression is:</u></em>

<h3><u>If y equals 5 what is x ?</u></h3>
Substitute y = 5 in given expression
5 = 57.15 - 0.5(x)
5 = 57.15 - 0.5x
0.5x = 57.15 - 5
0.5x = 52.15
Divide both sides by 0.5
x = 104.3
Thus when y equals 5, x is 104.3
<h3><u>If y = 3 what is x ?</u></h3>
Substitute y = 3 in given expression
3 = 57.15 - 0.5(x)
3 = 57.15 - 0.5x
0.5x = 57.15 - 3
0.5x = 54.15
Divide both sides by 0.5
x = 108.3
Thus when y equals 3 then x is 108.3
Answer:
B6Br4
Explanation:
Chemical formula gives a representation of the number of atoms that each element in a compound or molecule. In this question which is asking to give the formula of hexaboron tetrabromide, the hexa means 6 while the tetra means four.
Since the number of atoms of each element is written as a prefix before the main element, this means that the chemical formula of hexaboron tetrabromide will be B6Br4.