How many milliliters of a 1: 5000 w/v solution of the preservative benzalkonium chloride can be made from 125 ml of a 0.2% w/v solution of the preservative? a. 1250 ml b. 2500 ml c. 625 ml d. 1875 ml

a. 1250 mL

Explanation:

We use the C1V1=C2V2 equation to solve this problem, with:

C1=1/5000=0,0002 w/v,             V1=?

C2=0,2%=0,2/100=0,002 w/v     V2=125 mL

Then:

V1=C2V2/C1=0,002*125/0,0002=125O mL

Thus, 1250 mL of the preservative 1:5000 w/v can be made from 125 mL of a 0,2% w/v solution.

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.