Answer:
An alcohol thermometer can measure the freezing point of a liquid that freezes at −80 °C.
Explanation:
A thermometer is a device used to measure temperature. A thermometer must contain a thermometric substance. A thermometric substance is any substance having a particular physical property that changes with temperature.
For all liquid-in-glass thermometers, the property that changes with change in temperature is the height of the liquid. There are two kinds of liquid-in-glass thermometers; mercury-in-glass thermometer and alcohol-in-glass thermometer.
Alcohol-in-glass thermometer measures very low temperatures up to as low as -115°C. If it measures such a low temperature, then it can efficiently measure -80°C hence the answer.
Alcohol-in-glass thermometers have a narrower temperature range than mercury-in-glass thermometer. The later is well adapter for the measurement bof higher tempetures up to 357°C.
Answer : Colloid
Explanation : Any colloid which consist of a solid evenly dispersed in a gas phase can be called as smoke. So, if smoke has to be given a matter of substance then it is can be categorized as a Colloid present in gaseous phase. Smoke is a solid which contains minute particles of dust which is homogeneously dispersed in the air.
Answer:
Initial rate of the reaction when concentration of hydrogen gas is doubled will be
.
Explanation:

Rate law says that rate of a reaction is directly proportional to the concentration of the reactants each raised to a stoichiometric coefficient determined experimentally called as order.
Initial rate of the reaction = R = 
![R = k\times [N_2][H_2]^3](https://tex.z-dn.net/?f=R%20%3D%20k%5Ctimes%20%5BN_2%5D%5BH_2%5D%5E3)
![4.0\times 10^5 M/s=k\times [N_2][H_2]^3](https://tex.z-dn.net/?f=4.0%5Ctimes%2010%5E5%20M%2Fs%3Dk%5Ctimes%20%5BN_2%5D%5BH_2%5D%5E3)
The initial rate of the reaction when concentration of hydrogen gas is doubled : R'
![[H_2]'=2[H_2]](https://tex.z-dn.net/?f=%5BH_2%5D%27%3D2%5BH_2%5D)
![R'=k\times [N_2][H_2]'^3=k\times [N_2][2H_2]^3](https://tex.z-dn.net/?f=R%27%3Dk%5Ctimes%20%5BN_2%5D%5BH_2%5D%27%5E3%3Dk%5Ctimes%20%5BN_2%5D%5B2H_2%5D%5E3)
![R'=8\times k\times [N_2][H_2]^3](https://tex.z-dn.net/?f=R%27%3D8%5Ctimes%20k%5Ctimes%20%5BN_2%5D%5BH_2%5D%5E3)

Initial rate of the reaction when concentration of hydrogen gas is doubled will be
.
If the crucible wasn't covered with a lid the reactants may have produced a gas that was released into the surroundings, or mass may have been lost in the form of water vapour.
Potassium or any other metals.