If the heat of formation of H2O(l) is –286 kJ/mol, which of the following thermochemical equations is correct?
(a) 2 H(g) + O(g) H2O(1)
AH = -286 kJ
(b) 2 H2(g) + O2(g) 2 H2O(1)
AH = -286 kJ
(c) H2(g) + 3 02(8) H2O(0
AH = -286 kJ
(d) H2(g) + O(g) →→ H2O(g)
AH = -286 kJ
(e) H2O(1) H2(g) + 2 02(8)
AH = -286 kJ
Practice Exercise 2

Which statement accurately describes the relationship between air pressure, air density, or altitude? as altitude increases, pressure increases. as altitude increases, air density increases. air pressure and density are lowest at sea level. denser air exerts more pressure than less dense air.

Which of the following best explains why the end of a spoon sticking out of a cup of hot water also gets hot? question 7 options: the heat from the hot water is conducted through the spoon handle the hot water heats the air surrounding the upper part of the spoon. the hot water causes a physical change in the spoon handle. the hot water causes a chemical reaction to take place in the spoon.

When balancing a chemical equation: