Answer: 
Explanation:Bond energy of H-H is 436.4 kJ/mole
Bond energy of C-H is 414 kJ/mol
Bond energy of C=C is 620 kJ/mol
Bond energy of C≡C is 835 kJ/mol

= {1B.E(C≡C)+2B.E(C-H) +1B.E(H-H)} - {1B.E(C=C)+4B.E(C-H)}


Answer:
True
Explanation:
magnesium and copper react with dilute acids to make salts and hydrogen gas
<u>Answer:</u> The amount of heat required to warm given amount of water is 470.9 kJ
<u>Explanation:</u>
To calculate the mass of water, we use the equation:

Density of water = 1 g/mL
Volume of water = 1.50 L = 1500 mL (Conversion factor: 1 L = 1000 mL)
Putting values in above equation, we get:

To calculate the heat absorbed by the water, we use the equation:

where,
q = heat absorbed
m = mass of water = 1500 g
c = heat capacity of water = 4.186 J/g°C
= change in temperature = 
Putting values in above equation, we get:

Hence, the amount of heat required to warm given amount of water is 470.9 kJ
Answer: 1.4x10-3 g N2O4
Explanation: First convert molecules of N2O4 to moles using Avogadro's Number. Then convert moles to mass using the molar mass of N2O4.
9.2x10^18 molecules N2O4 x 1 mole N2O4 / 6.022x10²³ molecules N2O4
= 1.53x10-5 moles N2O4
1.53x10-5 moles N2O4 x 92 g N2O4/ 1 mole N2O4
= 1.4x10-3 g N2O4