The law of blank of mass states that in any physical or chemical change, matter is neither created nor destroyed.

How many atoms are in 45.6 g gold, Au

A graduated cylinder was filled with 25.0 mL of liquid. A solid object weighing 73.5 g was immersed in the liquid, raising the liquid level to 43.9 mL. Calculate the density of the solid object.

In general, the nucleus of a small atom is stable. Therefore, over very short distances, such as those in a small nucleus, a. the strong nuclear force equals the electric force. b.

How does the energy of an electron change when the electron moves closer to the nucleus

A chemist prepared aqueous solutions of two weak acids: solution A is hydrazoic acid (HN3), and solution B is propanoic acid (HC2H5CO2). At 25°C, the acid-dissociation constant (Ka) for hydrazoic acid is 2.

Hypervitaminosis is a serious health threat associated with excessive amounts of ingested fat-soluble vitamins. why do water-soluble vitamins not commonly pose the same threat?

Hydrogen is an element with two naturally occurring isotopes: 2 H and 3 H. This means that 2 H, which has a mass number of 2, has fewer than 3 H, which has a mass number of 3. True/False

C₂H₂ + O2 - CO₂ + H₂ How many moles of oxygen are necessary to react completely with 4.0 moles of propane (CH) ?

What are the two main classifications of energy resources?

A liquid is heated and a solid forms at the bottom of the beaker. Is this a physical or chemical change?