Which of the following occurs when a catalyst is used in a chemical reaction? A. the catalyst speeds up the rate of the chemical reaction
B. the catalyst always brings the reactants close together
C. the catalyst is permanently changed by the reaction
D. the catalyst increases the activation energy needed for the reaction to take place

What type of light does this light bulb produce most (i. e. at what wavelength does the spectrum have maximum intensity)?

Which notation is used to represent an alpha particle? a. b. c. d.

I'm thinking it's 2 you are asked to explain the earth's magnetic field. which is the best reply? 1. the earth's magnetic south is similar to the north pole of a magnet. 2. the earth's core has a strong magnetic charge similar to the south pole of a magnet. 3. the earth's geomagnetic south is similar to the south pole of a magnet. 4. the earth's magnetic charge is not centered at either pole; it varies based on location.