River's chemistry class is doing an experiment in which the students create a 30% hydrochloric acid mixture by mixing a certain amount of 25% solution with a different amount of 50% solution. The amount of 25% solution used is 20 liters less than 5 times the amount of 50% solution used. How much of the 25% solution and the 50% solution are needed in all

20 liters of 50% solution and 80 liters of 25% solution

Explanation:

Let x litres be the amount of 50% solution to be used.

Since the amount of 25% solution used is 20 liters less than 5 times the amount of 50% solution used, then the 25% solution would be (5x -20) litres.

Therefore, 50x + 25(5x-20) = 30(x + 5x-20)

50x + 125x - 500 = 30x + 150x - 6 00

175x - 500 = 180x - 600

Collecting like terms

180x - 175x = 600 - 500

5x = 100

x = 20

Therefore, volume of 50% solution needed = 20 litres

Volume of 25% solution needed = (5 * 20) - 20 = 80 litres

20 liters of 50% solution and 80 liters of 25% solution

2b2t

explanation:

2b2t

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.