Which of these is a typical property of a substance that is composed of atoms that are held together by covalent bonds?
it conducts electricity when in solid form.
it conducts electricity when in molten form.
it conducts electricity when it is dissolved in water.
it does not conduct electricity in any form.

How much energy is required to vaporize 2 kg of copper? a 4730 kj b 207kj c 9460 kj d 414kj

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?

Jill is pushing a box across the floor. which represents the upward force perpendicular to the floor? a) fp b) ff c) fn d) fg