Endothermic reaction definition chemistry

Why is there day and night

This element is the halogen in the 4th period.

Substances x and y are examples of which kind of molecule?

Which term best defines the controlled, measured addition of the amount of a solution of known concentration required to react completely with a measured amount of a solution of unknown concentration?

How does the ph of an acid compared to the ph of a base?

In solid KCl, which has the same solid state structure as NaCl (simple cubic unit cell), the distance between the ions is 314 pm. Calculate the length of the edge of the unit cell.

Planck's constant is approximately equal to which of the following? The product of the uncertainties in electron position and electron momentum. The sum of the uncertainties in electron position and electron momentum.

Which is the MOST accurate description about how the different types of feedback mechanisms work

Which of the following equations violates the law of conservation of mass? A) 2Al + 6HCl yields 2AlCl3 + 3H2 B) Na2C2O4 + Pb (NO3) 2 yields PbC2O4 + 2NaNO3 C) AgNO3 + LiCl yields AgCl + LiNO3 D) 3Ca + 2Cr (NO3) 3 yields 3Ca (NO3) 3 + 2Cr

Which of the following is a true statement about energy? a. energy can be created and destroyed. b. energy is never created nor destroyed. c. energy is easily created, but cannot be destroyed. d. energy cannot be converted from one form to another.