What is mass? is it just particles?

A sample of hydrogen gas occupies 17.5 L at STP. How many moles of the gas are present? Answer in units of mol.

A student is trying to dissolve 20 grams of sugar in a beaker containing 250 milliliters of water at room temperature. What can the student do to make the sugar dissolve faster in the water?

1-Which reaction shown below is carried out by nitrifying bacteria? I will mark you as brainlist Choose: A.{ammonium} to {nitrate} B.{nitrate} to {nitrogen gas} C.{nitrogen gas} to{ammonium}

How many grams of mercury are needed to react completely with 157g of sulfur to form hgs?

Knowing the reactions between hydrogen gas and oxygen gas to form water is exothermic which would you say is greater: the average bond energies for hydrogen and oxygen or the bond energies for water? Explain.

If you went to the moon, how would your mass change relative to your mass on Earth? It would be the same on the moon as on Earth It would increase because of less gravity It would decrease because of less gravity None of the above

The pH of a solution is 2.60. What is the [H3O+] for the solution? 2.51 * 102 M 3.98 * 102 M 2.51 * 10-3 M 3.98 * 10-3 M

there are 25 elements found in living things. how many of these elements are found in some organisms but not at all?

What is every stored in atomic bonds called

What happens to energy when Sally kicks a soccer ball? A. Kinetic energy is transformed to chemical energy in muscles. B. Potential energy is transformed to chemical energy in muscles. C. Kinetic energy is transferred from the leg to the soccer ball.