Which one of this is endothermic and which one is exothermic?

CH2+O2 - > CO2+H2O+Energy

CaCo+Energy - > CaCo+CO2

What is the percent mass of C8H10 when 123 g of C8H10 dissolved in 765 g of C6H6? Express your answer to three significant figures.

How many kilograms of the rock must be processed to obtain 2.0 kg of Pb?

Suppose a sample of air can hold at most 10 grams of water vapor. If the sample actually had 2 grams of water vapor, what is its relative humidity

What standard reduction electrode has a half-cell potential of 0.00 V? Oxygen hydrogen lithium Fluorine

Which set of numbers gives the correct possible values of I for n = 2? 0 0,1 O, 1, 2 O, 1, 2, 3

How does an atom with too few neutrons relative to protons undergo radioactive decay? * by converting proton to a neutron by converting a neutron to a proton by emitting an alpha particle

What is the chemical formula for the compound formed between sodium and iodine?

8. Write a balanced chemical equation showing how you could prepare each of the following salts from an acid-base reaction: KNO3, NaBr, and Cas.

Is calcium carbonate a compound element or mixture?

Why do covalent bonds not involve the transfer of electrons