Which statement describes evidence of a chemical reaction?

a. ice melting

b. water boiling

c. lighting a match

d. grape juice freezing

The ionization energy for a hydrogen atom is 1.31*106 J/mol. What is the ionization energy for He+?

Spots drinks contain sugar, salt, and flavorings dissolved in water. They can be made more or less sweet by adding different amounts of sugar. It is a mixture or compound?

What are three physical factors that can be done to speed up a chemical reaction

The enthalpy of combustion of acetylene C2H2 is described by C2H2 (g) + (5/2) O2 (g) →2CO2 (g) + H2O (l),  H rxn = - 1299 kJ/mol.

Radium-221 has a half-life of 30 sec. How long will it take for 96% of a sample to decay?

When magnesium combines with sulfur to form magnesium sulfide, it is oxidized to Mg2+. Which statement is true about this reaction? A. It involves gain of electrons. B. It involves loss of electrons. C. It involves loss of oxygen. D.

Equilibrium reaction chromate

How does food in a fridge cool down

How many electrons would be found in the ion whose symbol is given below? N3-

In an atomic model that includes a nucleus, positive charge is a. located in the space outside the nucleus. b. spread evenly throughout an atom. c. concentrated at multiple sites in an atom. d. concentrated in the center of an atom.