A substance that speeds up the rate of a chemical reaction is called

a. a catalyst

b. a substrate.

c. an enzyme.

d. Both A and C

The ionization energies of several of the Group 1 elements in the periodic table are shown in the table below

The half-life of Radium-226 is 1590 years. If a sample contains 100 mg, how many mg will remain after 4000 years?

Which one of the following statements is not true for a compound to be considered as aromatic? A. The compound must be cyclic and planar B. The compound must be monocyclic. C.

Which of the following pairs have the same specific heat? a. 1 g of solid lead; 10 g of solid lead?

Which is most like a scientific model? A. a thermometer B. an inch C. an element D. a map

At 400 K, the rate of decomposition of a gaseous compound initially at a pressure of 12.6 kPa, was 9.71 Pa s-1 when 10.0 per cent had reacted and 7.67 Pa s-1 when 20.0 percent had reacted. Determine the order of the reaction.

What particles are used to form bonds

Explain how antimony is useful for humans. What is it used for?

Classify these compounds as ionic or molecular. ncl3 nabr

If 3.64g of sand is separated from 5.25g of a mixture of salt and sand what is the percentage of sand in the sample