Moles = weight in grams / molecular weight.
So I would divide the "grams of barium" by its molecular weight (which is 137.3) to get "moles of barium". :)
Enyzmes speed up all chemical reactions
(Just took an AP Bio test with this question on it)
Answer:
A combustion reaction
Explanation:
C
organic compound(contains carbon) reacts with oxygen to give out carbon dioxide and water is a complete combustion.
1M KCl will require 25 mL to generate 100 mL of 0.25M KCl.
Molarity of a solution is defined as number of moles of solute present in 1000 mL of the solution.
So molarity is inversely proportional to the volume of the solution.
As solution is diluted. Molarity of the solution decreases.
1M of KCl means 1 mole of KCl in 1000 mL of the solution.
1M KCl is four times as concentrated as 0.25M KCl.
Therefore, to make 100 mL of 0.25M will require 
of 1M KCl diluted to 100 mL of distilled water.
Easy alternative: Dilution formula
Where 
are volume and concentration of first solution
and 
are of second solution.
Learn more about dilution formula here,
brainly.com/question/18917740
#SPJ4
The answer is -60.57. With appropriate sig figs it becomes -60.6 KJ.
<span>I think you were on the right track. However you need to multiply H2O by its coefficient from the balanced equation. Then you also need to keep in mind the signs. </span>
<span>Maybe it's easier if I write what I did out: </span>
<span>2H2O > 2H2 +O2...............-H= 2* -285.83 </span>
<span>Ca + O2 + H2 > Ca(OH)2....H= -986.2 </span>
<span>2C + H2 > C2H2.................H= 226.77 </span>
<span>The above H's stand for standard enthalpy of formations. These can be found in textbook appendix. Notice the negative infront of the enthalpy (H) for H2O. This is to remind me/you that the heat lost is gained in the rxn. </span>
<span>So then you add them up. 226.77 - 986.2 + (2*285.83) = -187.77 </span>
<span>Add back the total enthalpy that is given in the question -187.77+127.2 = -60.57 </span>
<span>If signs cross you up find a way to remember that works for you. </span>
