Which of these is true of a chemical reaction

a. Energy is either released or absorbed.

b. Energy is always absorbed.

c. Energy is always released.

d. Energy is not transferred.

Q. 40 g of water. specific heat of water is 4.18 J/g*°C. temperature changes from 20° C to 25°C, how much heat energy (Q) moves from the water to the surroundings? a 3,344 J b 836 J c 4,180 J d 209 J

Zinc reacts with hydrochloric acid according to the reaction equation Zn (s) + 2 HCl (aq) ⟶ ZnCl2 (aq) + H 2 (g) How many milliliters of 5.00 M HCl (aq) are required to react with 8.05 g Zn (s)

Any change that alters a substance without changing it into another substance.

Which one of the following statements is correct. a. an electron has a neutral electrical change, b. An electron has a negative electrical change. c. An electron is located inside the nucleus of an atom. d. An electron is much larger than an atom.

Select the choice that best completes the following sentence. Simple machines A. cannot be combined to make compound machines. B. are tools that make work easier. C. reduce the amount of energy needed to do work. D.

Calculate the volume of a 0.323-mol sample of a gas at 265 K and 0.900 atm.

What is the molar mass of the following substance : Cs2CO3

What does the velocity of a wave describe

Sulfur (S) has 16 protons and 16 neutrons. How many electron shells does an element of sulfur have?

Which one of the following statements about orbital energies is incorrect? A) The energy of a given orbital increases as the nuclear charge Z increases. B) In many-electron atoms the energy of an orbital depends on both n and l.