Is making ice cream a physical or chemical change

What is the result of multiplying (2.5 × 1010) × (2.0 × 10-7)? a. 5.0 × 103 b. 5.0 × 10-3 c. 5.0 × 1017 d. 5.0 × 10-17

Which type of substance ionizes partially and gives off hydrogen ions when dissolved in water? a. strong acid b. strong base c. weak acid d. weak base

Long term exposure to waves can cause sunburns and skin cancer. a) visible b) infrared c) gamma rays d) ultraviole