To transform electrical energy into mechanical energy, the electromagnet in a motor must rotate in just one direction. What allows this consistent rotation
to occur?
O A. The terminals of the battery frequently switch polarity.
O B. The electric current in the loop of wire frequently reverses
direction.
O C. The commutator frequently causes the loop of wire to turn.
O D. The poles of the permanent magnets frequently switch places.
SUBMIT

The combustion of methane, ch4, releases 890.4kj/mol. that is, when one mole of methane is burned,890.4 kj are given off to the surroundings. this meansthat the products have 890.4 kj less than the reactants.thus, ah for the reaction = - 890.4 kj. a negative symbolforah indicates an exothermic reaction.ch (g) + 20 (g)> co2 (g) + 2 h0 (1); ah = - 890.4 kga) how much energy is given off when 2.00 mol of ch,are burned? b) how much energy is released when 22.4g of ch. areburned?