Heating a substance causes molecules to speed up and spread slightly further apart, occupying a larger volume that results in a decrease in density. Cooling a substance causes molecules to slow down and get slightly closer together, occupying a smaller volume that results in an increase in density.
From: www.middleschoolchemistry.com
The trajectory of their motion knocked the Earth into a different orbit.
Answer:
1= 2H₂ + O₂ → 2H₂O
2=CaCo₃ + heat → CaO +CO₂
3=CH₄ + 2O₂ → CO₂ +2H₂O
4=HCl + NaOH → NaCl + H₂O
Explanation:
1 = Simple composition
The formation of water molecule is simple composition reaction. In this reaction two hydrogen atoms react with one oxygen atom and form one water molecules.
2H₂ + O₂ → 2H₂O
The amount of energy released is -285.83 KJ/mol. It is exothermic reaction.
2 = Simple decomposition reaction:
The break down of sodium hydrogen carbonate into sodium carbonate, carbondioxide and water is decomposition reaction. The decomposition reactions re mostly endothermic, because compound required energy to break.
2NaHCO₃ + heat → Na₂CO₃ + H₂O + CO₂
It is endothermic reaction.
Another example is:
CaCo₃ + heat → CaO +CO₂
3 = Combustion reaction
Consider the combustion of methane:
CH₄ + 2O₂ → CO₂ +2H₂O
The burning of methane is exothermic. The combustion reactions are exothermic because when fuel are burns they gives energy.
4 = Neutralization reaction
The neutralization reactions are those in which acid and base react to form the salt and the water. Some neutralization reactions are exothermic because they release heat. e.g
Consider the neutralization reaction of HCl and NaOH.
HCl + NaOH → NaCl + H₂O
Natural selection makes it so that an organism from a species has a better chance of surviving than an organism in the same species, but with different traits. Survival of the fittest proves that certain traits can help an organisms survive better than its peers. For example, say there was an allele that made bears have thicker fur than others. The year-round climate is extremely cold. The bears with thicker fur are more likely to survive due to the warmth their fur provides and will have more offspring. The bears with thinner fur will die more often and not produce healthy offspring due to the frigid temperature. Eventually, the allele for thin fur will die out because the bears with these alleles cannot survive in their habitat.
Answer: The molarity of this solution is 0.159 M.
Explanation:
Given: Mass of solute = 16.3 g
Volume = 1.75 L
Number of moles is defined as the mass of substance divided by its molar mass.
Hence, moles of NaCl (molar mass = 58.44 g/mol) ar calculated as follows.
Molarity is the number of moles of a substance present in a liter of solution.
So, molarity of the given solution is calculated as follows.
Thus, we can conclude that the molarity of this solution is 0.159 M.
