Calculate the change in the internal energy of a system when it releases 140 J of heat to the surroundings and does 85 J of work on the surroundings at the same time.

What is the ground-state electron configuration of copper (Cu) atom?

When the equation below is properly balanced with the smallest set of whole numbers, the coefficient in front of O2 is __________. NH3 + O2   → NO  +  H2O2  

How many moles of iron (Fe) are in 88.63 g of Fe3O4 (molar mass: 231.53 g/mol)?

How many carbon atoms are in 20.0 g of C3H6 (molar mass: 42.08 g/mol)?

What is the valence electron configuration of In (element #49)?

Given that 1 inch (in) = 2.54 cm, 33.8 in2 = ________ cm2

In general, electronegativity ____ down a group and ____ from left to right across a period.

What is the approximate measure of the indicated H-C-C bond angle in the following molecule?

What is the mass of NaNO3 (molar mass: 84.99 g/mol) needed to prepare 500.0 mL of 1.30 M NaNO3 solution?