A microwave oven has a power requirement of 1,239 W. A frozen dinner requires 4.4 min to heat on full power. (a) How much electrical energy (in kWh) is used?  ____ kWh (b) If the cost of electricity is 15¢ per kWh, how much does it cost to heat the dinner? (Do not round your final answer. Fractional cent values are acceptable.) ____ ¢

1.42 (a) and (b)

If 227.9 Joules of heat are added to 25.96 grams of a liquid, raising the temperature of the liquid from 27°C to 33.8°C, what is the specific heat capacity of the liquid with units of J/g•°C? Report your answer with 3 significant figures.

Part A If 52 J of heat is added to an aluminum can with a mass of 29.1 g , what is the temperature change? The specific heat capacity of aluminum is 0.903 J/g°C. Express your answer using two significant figures. ΑΣφ AT = °C

1. How much heat, in joules and in calories, must be added to a 75.3 g chromium block with a specific heat of 0.450 J/g·°C to increase its temperature from 25°C to its melting temperature of 1907°C?  J  =  cal = 2. A piece of unknown substance weighs 45.9 g and requires 2730 J to increase its temperature from 23.1°C to 88.9°C. (a) What is the specific heat (in J/g·°C) of the substance?  J/g·°C (b) If it is one of the substances found in the table below, what is its likely identity? Specific Heats of Common Substances at 25°C and 1 bar Substance Symbol (state) Specific Heat (J/g·°C) gold Au(s) 0.129 copper Cu(s) 0.384 iron Fe(s) 0.449 argon Ar(g) 0.521 silicon Si(s) 0.712 carbon dioxide CO2(g) 0.843 aluminum Al(s) 0.904 nitrogen N2(g) 1.039 water H2O(l) 4.1801 helium He(g) 5.196

Copper and zinc have have the same specific heat, (0.39 J/g x 1/C), how might you determine which metal you have as an unknown ?

If 901 J of heat is available, what is the mass in grams of iron (specific heat = 0.450 J/g･°C) that can be heated from 22.5°C to 120.0°C?

Part A Ammonia reacts with oxygen according to the equation: 4NH3(g) + 502(g) → 4NO(g) + 6H20(g), AHrxn = -906 kJ Calculate the heat (in kJ) associated with the complete reaction of 155 g of NH3. Express the heat in kilojoules to three significant figures. V ΑΣΦ ? heat = kJ Submit Previous Answers Request Answer

A)   An iron nail with a mass of 12 gg absorbs 15 J of heat. If the nail was initially at 30 ∘C, what is its final temperature? Express your answer using two significant figures. B) When 47.1 J of heat is added to 13.8 g of a liquid, its temperature rises by 1.74 ∘C. What is the heat capacity of the liquid?

If 901 J of heat is available, what is the mass in grams of iron (specific heat = 0.45 J/g･°C) that can be heated from 22.5°C to 120.0°C?