Enter the appropriate symbol for an isotope of calcium-42 corresponding to the isotope notation AZX

Which explanation of the solar system best fits the observations of the planets and how they orbit the sun? Question 20 options: A comet hit the sun and sent off fragments that became the planets.

Which of the following is separated by physical mean.? a) Radicals b) compounds c) elements d) mixture

WiFi, which allows wireless access to the internet, uses which electromagnetic wave? A. Infared light B. Radio waves C. Ultraviolet light D. Microwaves

When a lamp is turned on, only about 10% of the energy is transformed into light. What happens to the rest of the energy? A. The remaining energy is destroyed B. Energy that is not transformed into light becomes thermal energy C.

How many electrons can be held in the innermost energy level of atoms

Which of these is not a covalent molecule? 1. F2 2. CO 3. LiF 4. NH3

Define buffer capacity. a. buffer capacity is the amount of acid or base that can be added to a buffer without destroying its effectiveness. b. buffer capacity is the amount of acid that can be added until all of the base is used up. c.

Which of the following is not a chemical reaction a) gas formation b) solid formation c) energy change d) state change

How many moles of copper are needed to react with sulfur to produce 0.25 moles Ol copper (1) sulfide according to the following reaction: 2 Cu + S + Cuzs

If you wish to warm 52 kg of water by 22 ∘c for your bath, find what the quantity of heat is needed. express your answer in calories cal.