Answer:
162.7miles/hr
Explanation:
Given parameters:
Distance covered by the train = 813.5miles
Time taken = 5hours
Unknown:
Speed of the train = ?
Solution:
Speed is a physical quantity.
It is mathematically expressed as;
Speed = 
So, input parameters and solve;
Speed = 
= 162.7miles/hr
Answer:
Populations have genetic variation.
The environment changes.
Organisms must have specific traits in order to survive and reproduce.
Explanation:
Natural selection provides an advantage during an adverse condition for organisms that have a rich genetic variation in their population.
Also, environmental changes induced natural selection whereby organisms must adapt to changes around them.
For organisms to survive, they must have specific traits that gives them a competitive reproductive advantage.
Among the choices given, the correct answer is the first option. Substance X most likely is a crystal, and substance Y most likely is a liquid. Substance X having a fixed volume describes a crystal because crystals occupy a certain volume. Substance Y is a liquid because liquids can still be compressed further in order to attain a more packed <span>structure.</span>
Molar mass of sodium=23g
2 mole sodium gives 2 g H2
i.e 46g sodium gives 2g H2
so 65.4g will give=2.84g H2
now no. of molecules = 2.8/2*avogadros number
Answer:
The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.
