Question

A scientist is working with two different concentrations of hydrochloric acid (HCI). One bottle is 80% HCI, and the other is 40% HCI. For their experiment they need 1 liter of 70% HCI.


How many liters of the 80% solution do they need?

How many liters of the 40% solution?​

Answer 1

Answer:

80% of HCl used is 0.75 of a liter

40% or HCl used is 0.25 of a liter.

Step-by-step explanation:

Comment

You need a total of 1 liter which has a concentration of 70%.

Let x be the concentration of the 80%  HCl

Let 1-x be the concentration of the 40% HCl

Solution

(1 - x)*40/100 + x*80/100 = 70/100 * 1           Multiply by 100

40*(1-x) + 80x = 70                                         Remove the brackets (left)

40 - 40x + 80x = 70                                       Combine

40 + 40x = 70                                                 Subtract 40  from both sides

40-40 + 40x = 70 - 40                                    Combine

40x = 30                                                          Divide by 30

x = 30/40

Answer

x = 0.75 of a liter

1-x = 0.25 of a liter.