What is the number of valence electron of (Na).?

Which the following accurately describes a trade-off of using nuclear energy to produce electricity? A. The energy source is renewable, but the power plant disturbs natural ecosystems by stopping the flow of rivers B.

All of the following are true for a catalyst except that it A. provides an alternative pathway for a reaction. B. increases the rate of a chemical reaction. C. provides a lower required activation energy. D. is consumed during a chemical reaction.

A container contains 3.5 L of hydrogen gas at 32 degrees * C. What will be its volume if the temperature increases to 97 degrees * C keeping the pressure constant?

Covalent bonds are stronger and an electron is shared between the atoms. true or false

How many electrons, protons, and neutrons does copper have?

Hydrogen peroxide decomposes to water and oxygen at constant pressure by the following reaction: 2H2O2 (l) → 2H2O (l) + O2 (g) ΔH = - 196 kJ Calculate the value of q (kJ) in this exothermic reaction when 3.

What is the concentration of hydronium in each of the following cases: [OH-] = 10-12 M? [OH-] = 10-2 M?

Which statement best explains why elements are matter? An element is a physical substance that has mass and takes up space. Elements are pure substances that cannot be divided chemically. Each element is a pure substance composed of one type of atom.

Which of the following best describes what causes the phases of the moon? The alignment of the sun, Earth, and moon The speed of the moon around the Earth The speed of the Earth around the sun The alignment of the planets

At which temperature would atoms of a He (g) sample have the greatest average kinetic energy? (1) 25°C (3) 273 K (2) 37°C (4) 298 K