Answer:What happens to the temperature of a substance during a phase change? Why does this happen?
Explanation:During a phase change the temperature remains constant. This is because the heat supplied to change the state of matter is used in breaking the intermolecular forces and other attractive forces. Therefore, the temperature remains constant as no heat is absorbed or released.
Mixture. Mixtures can be separated into their component parts, while substances are chemically bonded atoms that can't be separated by physical means.
Answer:
See explanation
Explanation:
Potassium is a metal. Remember that metals are electropositive in nature. This implies that they give out electrons when they undergo ionic bonding with nonmetals.
Chlorine is a nonmetal. So the bond between chlorine and potassium is ionic. Potassium gives out one electron to chlorine and the both ions now attain a stable octet.
The electronic configuration of potassium is [Ar]4s1. After giving out an electron to chlorine in an ionic bond, its electronic configuration is now [Ar].
Answer: 0.887 g of 
should be added to excess HCl(aq).
Explanation:
According to ideal gas equation:
P = pressure of gas = 805 torr = 1.06 atm (760torr=1atm)
V = Volume of gas = 235 ml = 0.235 L
n = number of moles = ?
R = gas constant =
T =temperature =
According to stoichiometry:
1 mole of chlorine is produced by = 1 mole of
Thus 0.0102 moles of chlorine is produced by = 
moles of
Mass of =
0.887 g of should be added to excess HCl(aq).
1 molecule of NO2 included N atom and 2 oxygen atoms, so a total of 3 atoms per molecule.
1.3 x 10^22 times 3 = 3.9 x 10^22 atoms
