Answer:
0° Celsius
Explanation:
The thermometer shows 0° Celsius which corresponds to 32° F.
Answer:
Because only a few bacterias can "fix" the atmosphere nitrogen.
Explanation:
The nitrogen at the atmosphere is in the form of N₂ and represents 78% of the atmosphere composition. The element is part of the constitution of nucleic acids and proteins, so the living beings needed them.
However, the animals and the plants can't catch the N₂. Some bacterias that live in mutualism with plants have this ability, and they "fix" the atmosphere nitrogen, transforming the N₂ in the ions nitrite (NO₃⁻) or ammonia (NH₃), which can be caught by the plants.
Them, when the primary consumers eat the plants they catch the nitrogen, which will be passed through the food chain.
So, it's difficult to pull nitrogen from the atmosphere into the nitrogen cycle of the biosphere because only a few bacterias can do it.
Answer:
B
Explanation:
The electrochemical series can be used to check if a particular element has a greater activity than the other. Firstly, on the electrochemical series, it can be seen that lead is at a higher position compared to mercury. All things being equal, it will show a higher activity than mercury and hence can knock it off its salt.
Although it is the Overall standard electrode potential that tells us if a reaction is feasible or not, we can use the activity series to quickly discern if the reaction is possible or not. The overall standard electrode potential of both is positive which makes the reaction to be feasible and hence lead can display mercury off its salt
Answer:
3 is the coefficient of oxygen.
Explanation:
Chemical equation:
CH₃OH + O₂ → CO₂ + H₂O
Balanced chemical equation:
2CH₃OH + 3O₂ → 2CO₂ + 4H₂O
The given reaction is combustion reaction. In this reaction methanol is burn in the presence of oxygen and produces carbon dioxide and water.
The balance equation show reaction also follow the law of conservation of mass.
This law was given by French chemist Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.
Answer : The 
for the reaction is, 54.89 KJ
Solution : Given,
Mass of ZnS = 48.7 g
Molar mass of ZnS = 97.474 g/mole
First we have to calculate the moles of ZnS.
The balanced combustion reaction is,
From the given reaction, we conclude that
As, 2 moles of ZnS gives energy = 220 KJ
So, 0.499 moles of ZnS gives energy = 
Therefore, the for the reaction is, 54.89 KJ
