It was a power supply of a circuit that was horizontal of the ladder where they controlled the circuit.
For the discovery of the elements polonium and radium. Prohibited from higher education in her native Poland (then controlled by Russia), she moved to Paris in 1891 and studied at the Sorbonne.
Answer:
94.58 g of 
Explanation:
For this question we have to start with the reaction:
Now, we can balance the reaction:
We have the amount of 
and the amount of 
. Therefore we have to find the limiting reactive, for this, we have to follow a few steps.
1) Find the moles of each reactive, using the molar mass of each compound (
).
2) Divide by the coefficient of each compound in the balanced reaction ("2" for and "1" for ).
<u>Find the moles of each reactive</u>
<u>Divide by the coefficient</u>
<u />
The smallest values are for , so hydrogen is the limiting reagent. Now, we can do the calculation for the amount of water:
We have to remember that the molar ratio between and is 2:2 and the molar mass of is 18 g/mol.
C the two students watered the seeds differently
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>
