Answer:
-105 kJ
Explanation:
The enthalpy change of a reaction is the sum of the energy of the bonds of the reactants and the products. The bonds at the reactants are being broken, so it's an endothermic reaction, so the bond energy must be positive.
The bonds at the products are being formed, so the process is exothermic, and the bond energy must be negative. There are being broken 1 N≡N bond and 3 H-H bonds, and are being formed 6 N-H bonds:
Reactants: 945 + 3*432 = 2241 kJ
Products: 6*(-391) = -2346 kJ
ΔH = 2241 - 2346
ΔH = -105 kJ
I'd say false because copper is what they used to drink out of in the middle ages, and it caused them to get very sick, so I doubt they would use copper in your mouth.
Explanation:
desk I have a lot of work and I will send it in the one
Answer:
B. observing that a bone placed in a beaker of acid becomes bendy
Explanation:
The hypothesis suggests that when chicken bones are placed in vinegar, they become bendy due to the loss of calcium in their bones.
Calcium is identified as the ossifying material that strengthens the bone. When the acid that makes up the vinegar comes in contact with it, calcium is removed from the bone.
Now we know that calcium has capabilities of reacting with acids.
This suggests that if we also place the bone in an acid, they will bend due to reaction of calcium in the bones with the acid.
