This substance can be used to find the general density of most substances. It has a density of 1.0 g/ml when it is at 4 degrees celcius. What is this substance?

When a spring is compressed, the energy changes from kinetic to potential. which best describes what is causing this change?

The activation energy for the reaction no2(g)+co2(g)⟶no(g)+co(g) is ea = 300 kj/mol and the change in enthalpy for the reaction is δh = -100 kj/mol . what is the activation energy for the reverse reaction?

20 grams of water. she poured out 15 grams. which of the following physical properties of the water changes? a .boiling point b. density c .electrical conductivity d .volume