Which of these is an indicator that a chemical reaction has occurred?

precipitate forms

temperature remains the same

color is diluted

mass increases

Analyze: The metallic character of an element is determined by how readily it loses electrons. Elements that lose electrons most easily have the greatest metallic character A. Which group has the greatest metallic character? B.

Scientists are studying how substance A and substance B react. When substance A and B are mixed, a substance different from A and B floats to the top of the solution. This is evidence that a (n). physical change occurred. endothermic change occurred.

How many orbitals does the p subshell contain

A scuba tank is being prepared for a deep sea dive 9 atms of He, 1.5 atms of Nitrogen gas and 6 atms of oxygen gas are added to the tank. What is the total pressure?

Electronegativity tends to increase from left to right across a row because

The part of a soil profile that is made up of partly weathered rock is the, bedrock subsoil, regolith, topsoil.

How many atoms are in a molecule

Analytical chemists can detect very small amounts of amoin acids, down to 3x10^-21 mol. how many molecules of an amino acid (mr=200) would this be?

Are Nighthowlers real and are they poisonous

An atom had a mass of 43 and it also has has 21 electrons