If 450.0 mL of a 0.500 M solution is mixed with 200.0 mL of water, what is the molarity of the new
solution?
A. 0.346 M
B. 0.625 M
C. 1. 86 M
D. 2.50 M

A) .346 M

Explanation:

Given:

- 450 mL

- .5 M soln

-200 mL water

1) Convert mL to L

450 mL = .45 L

200 mL = .2 L

2) Find mols in solution

.5 M = x/.45 L

x = .225 mol

3) Find total volume of solution

.45 L + .2 L =.65 L

4) Find new molarity

molarity (M) = mols solute/ L solution

y = .225 mol (from step 2)/ .65 L (from step 3)

y = .346 M

A) .346 M

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !

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