Answer:
destroyed, from, endothermic
Explanation:
Energy is conserved in chemical reactions. It is neither created nor destroyed but can be transferred from one form to another.
An exothermic reaction transfers energy from the reacting substance to the surroundings. The body of the container feels warm. An exothermic reaction has a negative value of enthalpy.
An endothermic reaction transfers energy from the surroundings to the reacting substance. The body of the container feels cold. In an endothermic reaction, enthalpy is positive.
Answer:
Covalent bonds usually occur between nonmetals. For example, in water (H2O) each hydrogen (H) and oxygen (O) share a pair of electrons to make a molecule of two hydrogen atoms single bonded to a single oxygen atom. ... Covalent compounds tend to be soft, and have relatively low melting and boiling points.
Answer:
They are both building blocks
Explanation:
DNA builds up life while legos build things
Answer:
Empirical Formula = C₁H₄ or CH₄
Explanation:
Data Given:
Mass of C = 12.0 g
Mass of H = 4 g
Step 1: <u>Calculate Moles of each Element;</u>
Moles of C = Mass of C ÷ At.Mass of C
Moles of C = 12.0 ÷ 12.0
Moles of C = 1.0 mol
Moles of H = Mass of H ÷ At.Mass of H
Moles of H = 4.0 ÷ 1.0
Moles of H = 4.0 mol
Moles of O = %O ÷ At.Mass of O
Moles of O = 53.924 ÷ 16.0
Moles of O = 3.370 mol
Step 2: <u>Find out mole ratio and simplify it;</u>
C H
1.0 4.0
1.0/1.0 4.0/1.0
1 4
Hence,
Empirical Formula = C₁H₄ or CH₄
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>
