Answer:
Air is less dense on a mountaintop than at sea level.
Air pressure is lower at low altitudes.
As you climb a mountain, air pressure increases.
More force pushes on the air at the bottom of an air column.
As you descend a mountain, air molecules are closer together.
Explanation:
Lets do process of elimination!
A. Breaking glass - That is a psychical change because if you break it, it is still glass. It didn't change to another substance.
B. Melting ice on a windshield - During the melting process, there is no chemical change, and therefore, no new substance is created.
C. Burning gasoline - When gas burns it usually combines with oxygen to give carbon dioxide, water etc. It is a chemical change.
D. Denting a bumper - The bumper is still a bumper, only thing is it has a dent in it. The properties did not change, meaning no chemical change.
Answer:
204g of NH3
Explanation:
The balanced equation for the reaction is given below:
N2 + 3H2 —> 2NH3
Next, we shall determine the number of mole NH3 produced by reacting 6moles of N2. This is illustrated below:
From the balanced equation above,
1 mole of N2 reacted to produce 2 moles of NH3.
Therefore, 6 moles of N2 will react to produce = 6 x 2 = 12 moles of NH3.
Finally, we shall convert 12 moles of NH3 to grams. This is illustrated below:
Number of mole of NH3 = 12 moles.
Molar mass of NH3 = 14 + (3x1) = 17g/mol
Mass of NH3 =..?
Mass = mole x molar mass
Mass of NH3 = 12 x 17
Mass of NH3 = 204g.
Therefore, 204g of NH3 will be produced from the reaction.
Answer:
Four electrons are present in the valence shell of Silicon.
Explanation:
Valence shell electrons are those electrons which are present in the outermost shell of an atom. These valence shell electrons are responsible for in the formation of bonds with other atoms.
Silicon having atomic number 14 has fourteen electrons in its neutral state and has the electronic configuration as follow;
1s², 2s², 2p⁶, 3s², 3p²
In given configuration the valence shell (outermost shell) is 3 and the number of electrons present in it are four i.e. 3s² and 3p² (2 + 2 = 4) respectively.
Hydrogen is usually –1. This is INCORRECT. The oxidation number for H is +1.
Oxygen is usually –2. This is CORRECT.
A pure group 1 element is +1. This is INCORRECT. It does not follow. This will depend on the other elements and the overall charge.
A monatomic ion is 0. This is INCORRECT. Diatomic ion is 0.
