Answer:
The answer is a.
Explanation:
Most of the costs associated with using renewable resources are due to overuse of the resources.
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>
Answer:
83.20 g of Na3PO4
Explanation:
1 mole of Na3PO4 contains 3 moles of Na+.
Mole of Na ion to be prepared = Molarity x volume
= 0.700 x 725/1000
= 0.5075 mole
If 1 mole of Na3PO4 contains 3 moles of Na ion, then 0.5075 Na ion will be contained in:
0.5075/3 x 1 = 0.1692 mole of Na3PO4
mole of Na3PO4 = mass/molar mass = 0.1692
Hence, mass of Na3PO4 = 0.1692 x molar mass
= 0.1692 x 163.94
= 83.20 g.
83.20 g of Na3PO4 will be needed.
Answer:
You'll have to record the observations in appropriate ways and organize them The way you collect your data should relate to how you're planning to analyze and use it These might for instance include entering numerical observations into a Qualitative data are collected as descriptions anecdotes opinions quote
Explanation:
Answer:
4- radioactive isotopes
Explanation:
I don't remember exactly but this question was on the regents
