2. Calculate the amount of heat in kilocalories produced by the burning of 52.4 g of methane (CH) in an excess of air according to the following equation:
CH, + 02 - CO2 + 2H,0 + 890kJ

Asample of silver (with work function ? = 4.52 ev) is exposed to an ultraviolet light source (? = 200 nm), which results in the ejection of photoelectrons. what changes will be observed if: silver is replaced with copper (? = 5.10 ev) more photoelectrons ejected no photoelectrons are emitted fewer photoelectrons ejected more energetic photoelectrons (on average) less energetic photoelectrons (on average)

If a 12-v battery is connected to a circuit that has a current of 3.0 a, what is the total resistance in the circuit? 36 ohms 4 ohms 0.25 ohms

If you burn 10 kilograms of wood in a fire (combustion) what is the weight of the products after the fire has finished burning the wood?