chem 1

What mass of water is produced from the complete combustion of 5.90×10−3 g of methane?

1.33×10−2 g

For a given sample of CH3OH, the enthalpy change during the reaction is 82.4 kJ . What mass of methane gas is produced?

10.5 g

Calculate the amount of heat transferred when 29.0 g of CH3OH(g) is decomposed by this reaction at constant pressure.

114 kJ

How many kilojoules of heat are released when 38.6 g of CH4(g) reacts completely with O2(g) to form CH3OH(g) at constant pressure?

304 kJ

A volume of 125 mL of H2O is initially at room temperature (22.00 ∘C). A chilled steel rod at 2.00 ∘C is placed in the water. If the final temperature of the system is 21.20 ∘C , what is the mass of the steel bar? Use the following values: specific heat of water = 4.18 J/(g⋅∘C) specific heat of steel = 0.452 J/(g⋅∘C)

48.2 g

Consider this combination reaction: 2Mg(s)+O2(g)→2MgO(s) ΔH=−1204 kJ What is the enthalpy for the decomposition of 1 mole of MgO(s) into Mg(s) and O2(g)?

602 kJ/mol

The specific heat of water is 4.18 J/(g⋅∘C). Calculate the molar heat capacity of water. Express your answer to three significant figures and include the appropriate units.

75.2 Jmol⋅∘C

First, launch the video below. You will be asked to use your knowledge of chemistry to predict the outcome of a demonstration. Then, close the video window and answer the questions at right. You can watch the video again at any point to review. When HCl(aq) and NaOH(aq) are mixed in a beaker, the beaker feels warm to the touch. What is known about the enthalpy of this reaction?

The reaction is exothermic.

Consider the following reaction: 2CH3OH(g)→2CH4(g)+O2(g),ΔH=+252.8 kJ You may want to reference (Pages 172 - 176) Section 5.3 while completing this problem. Is this reaction exothermic or endothermic? exothermic endothermic

endothermic

Calculate ΔE, if a system releases 66.7 kJ of heat to its surroundings while the surroundings do 44.0 kJ of work on the system. Express your answer using two significant figures.

ΔE = -23 kJ