Sodium metal forms at the cathode
Answer:
b) The dehydrated sample absorbed moisture after heating
Explanation:
a) Strong initial heating caused some of the hydrate sample to splatter out.
This will result in a higher percent of water than the real one, because you assume in the calculation that the splattered sample was only water (which in not true).
b) The dehydrated sample absorbed moisture after heating.
Usually inorganic salts may absorbed moisture from the atmosphere so this will explain the 13% difference between calculated water percent the real content of water in the hydrate.
c) The amount of the hydrate sample used was too small.
It will create some errors but they do not create a difference of 13% difference as stated in the problem.
d) The crucible was not heated to constant mass before use.
Here the error is small.
e) Excess heating caused the dehydrated sample to decompose.
Usually the inorganic compounds are stable in the temperature range of this kind of experiments. If you have an organic compound which retain water molecules you may decompose the sample forming volatile compounds which will leave crucible so the error will be quite high.
Answers:
1. B.)
2. Both A.) and B.)
3. A.)
Step-by-step explanation:
1. Ions in gas phase
A plasma is a gas consisting of electrons and positively charged ions.
Because the particles are ions and electrons, rather than neutral atoms or molecules as in ordinary gases, scientists consider a plasma to be a fourth state of matter<em>.</em>
2. Kinetic Molecular Theory
Both activities illustrate the postulate.
A.) If the particles are extremely small and far apart, most of the volume of a gas is empty space. That's why it's easy to push the plunger of a capped nozzle syringe containing a gas.
B.) If the particles are far apart, it's easy for a coloured gas to spread into an inverted jar placed on top of a jar containing the gas.
3. Hot air balloon
The high temperature in the balloon makes the gas molecules spread apart according to Charles's law, because this law describes how a gas will behave at constant pressure.
As the hot air escapes from the vent, the combined mass of balloon + hot air becomes less than the mass of cold air that it displaces, and the balloon rises.
B.) is <em>wrong</em>. Boyle's law applies only when both the number of moles and the temperature remain constant.
Answer:
2200 L
Explanation:
Ideal gas law:
PV = nRT,
where P is absolute pressure,
V is volume,
n is number of moles,
R is universal gas constant,
and T is absolute temperature.
The initial number of moles is:
(110 atm) (80 L) = n (0.0821 L atm / K / mol) (30 + 273.15) K
n = 353.58 mol
After some gas is removed, the number of moles remaining is:
(80 atm) (80 L) = n (0.0821 L atm / K / mol) (30 + 273.15) K
n = 257.15 mol
The amount of gas removed is therefore:
n = 353.58 mol − 257.15 mol
n = 92.43 mol
At normal conditions, the volume of this gas is:
PV = nRT
(1 atm) V = (92.43 mol) (0.0821 L atm / K / mol) (273.15 K)
V = 2162.5 L
Rounded, the volume is approximately 2200 liters.
