Which of the following is true about melting point determination?
a. at the melting point of a substance, the solid and vapor states exist in equilibrium.
b. an impure compound has a narrow, sharp melting point range.
c. a solid is said to sublime when it first liquefies and then vaporizes to a gas.
d. at the eutectic point, the melting point of a mixture of two compounds is sharp.
e. although a substance may exist in different crystalline forms, it has only one characteristic melting
point.

Lewis structure and molecular geometry for nh2cl

Which of the following statements about acidic water is true? a. acid has no effect on the h,o molecules. b. the solution contains a larger number of oh ions than h,o ions. c. the solution contains a larger number of h,o ions than qh ions. d. the solution contains an equal number of h,o ions and oh ions. none of the above e.

Select the correct answer from each drop-down menu.describe what happens to a carbon-11 atom when it undergoes positron emission.the decay of a carbon-11 atom _1_, and this causes it to emit _2_.options for 1: > changes a neutron into a proton> changes a proton into a neutron> is hit with a neutron> reconfigures its protons and neutronsoptions for 2: > a negatively charged electron-sized particle> a positively charged election-sized particle> two atoms and several neutrons> two neutrons and two protons