61. If a 1.0 M solution of HA, a weak acid, has a pH of 2.0, then the value of Ka, the acid-dissociation constant, for HA is closest to A. 1.0 × 10-4 B. 1.4 × 10-4 C. 1.0 × 10-2 D. 1.4 × 10-2 E. 1.4 × 10-1

When balancing a chemical equation:

The twister and runaway train are two coasters at the same amusement park. both coasters start at the same height. the coaster for the twister is twice the mass of the coaster for the runaway train. which roller coaster has greater gravitational potential energy at the start of the ride?

What is the ph of a solution that has a hydrogen ion concentration of 1.0 * 10 -9 m?