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1. (2 points) Elemental iron is produced in what is called the thermite reaction

ID: 1044946 • Letter: 1

Question

1. (2 points) Elemental iron is produced in what is called the thermite reaction because it produces enough heat (850.0 kJ of heat energy) that the iron is initially in the molten state. The balanced thermite reaction is shown below. What mass (in grams) of aluminum is needed to produce 35.8 kJ of heat energy? 2Al (s) + Fe2Os (s) -> A2Os (s) +Fe () AH -850.0 kJ 2. (2 points) Let's say I'm using a portable gas burner to heat this water. This burner uses propane (CHsCH2CH3) gas as the fuel source. Given the following equation, how much propane (in grams) would I need to provide enough heat to raise the temperature of 1500.0 g of water from 22.2 C to 100.0°C? The molar mass of propane 44.1 g/mol. ??????? (g) + 502 (g) 3CO2 (g) + 4H20 () H-2220 kJ (2 points) Let's say I'm preparing a large pot of water with the intention of cooking pasta. I'm trying to heat 2000.0 g of water (about 8.5 cups) from 22.5 °C (about room temp) to 100.0 °C (boiling point of water). How much heat (in kJ) would I need to add to the water to reach 100.0 °C? (note: the specific heat of water is 4.184 J/g.°c) 3.

Explanation / Answer

Ans 1 :

2 moles of Al weighing 53.96 g releases 850.0 KJ of energy

So the mass of Al required to release 35.8 KJ of energy will be :

= ( 35.8 x 53.96) / 850.0

= 2.27 grams