HELP PLS

Calculate the mass percentage of water in the formula Na2OCO3 x 10H20

Achemical reaction (also known as a chemical change) produces substances that are chemically different from the starting materials. an example of a chemical reaction is the formation of water from hydrogen and oxygen gas.in a physical change, a substance changes its physical appearance but not its chemical identity. an example of physical change is the formation of liquid water from solid water, a familiar process called melting. physically, liquid water looks very different from solid water (ice) but the chemical identity, water, is the same for both. which of following changes that affect the composition of our atmosphere involve physical changes and which involve chemical reactions? oxygen gas changes to ozone during thunderstorms carbon dioxide is produced by the combustion of gasoline in an automobile engine. when coal, oil, and natural gas are decomposed in landsills they produce methane gas. freezing rain develops when a warm air mass overrides a cold air mass. fog forms from water vapor when the temperature drops below the dew point

What is the mass of 0.46 mol of mgcl2

The table lists the lattice energies of some compounds.compoundlattice energy (kj/mol)lif            –1,036licl            –853naf            –923kf            –821nacl            –786which statement about crystal lattice energy is  best  supported by the information in the table? the lattice energy increases as cations get smaller, as shown by lif and kf.the lattice energy increases as the cations get larger, as shown by lif and licl.the lattice energy decreases as cations get smaller, as shown by nacl and naf.the lattice energy decreases as the cations get smaller, as shown by naf and kf.