How many moles of NH4SO4 are in 17.492 grams

The enthalpy of formation of water is -285.8 kj/mol. what can be inferred from this statement?

Write the symbol for every chemical element that has atomic number greater than 3 and atomic mass less than 12.0 u.

There is a single path for electrons. the current decreases when additional resistors are added. the current will be the same in each resistor. these statements best describe a(n) circuit.