Answer:
Pure substances are made up of a bulk quantity of individual atoms or molecules.
Each pure substance is made up of one of Individual atoms of the same type that are connected to form extended structures.
A chemical reaction happens when substances break apart or combine to form one or more new substances.
- New substances form when bonds break and new bonds form.
Answer:
by using this formula you will get it
Explanation:
number of mole = number of particles÷ Avogadro's number
n=3.51×10^23÷ 6.02×10^23
n = 0.58 moles
Answer : The fuel value and the fuel density of pentane is, 49.09 kJ/g and respectively.
Explanation :
Fuel value : It is defined as the amount of energy released from the combustion of hydrocarbon fuels. The fuel value always in positive and in kilojoule per gram (kJ/g).
As we are given that:
Fuel value =
Molar mass of pentane = 72 g/mol
Fuel value =
Fuel value = 49.09 kJ/g
Now we have to calculate the fuel density of pentane.
Fuel density = Fuel value × Density
Fuel density = (49.09 kJ/g) × (0.626g/mL)
Fuel density = 30.73 kJ/mL =
Thus, the fuel density of pentane is
Answer:
Hi the answer should be B or 2
Explanation:
Hope this helps!
Answer:
Explanation:
This question is incomplete. However, let's understand what a single displacement reaction is and what occurs during such reactions.
A single displacement reaction is a reaction in which a more reactive element displaces/replaces a less reactive element in a compound. The reactions below depict a single displacement reaction.
A + BC ⇒ AC + B
2Al + Fe₂O₃ ⇒ Al₂O₃ + 2Fe
During chemical reactions, heat is either absorbed from the environment (endothermic reaction) or given off into the environment (exothermic reaction). <u>During bond formation (in a reaction), heat is released into the environment (exothermic) while when bonds are broken, heat is absorbed from the environment (endothermic).</u>
During single displacement reaction, heat is given off, hence single displacement reaction is an exothermic reaction because it involves the formation of a bond (for the compound formed in the product).
Please note that <u>it can be argued that bonds were also broken in the reactants before new ones are formed in the products, however the bonds broken in the reactant do not require much heat from the environment because the more reactive element ordinarily has a higher activity than the displaced element thus, the entire reaction produces heat (exothermic) when the new bond is being formed</u>.
What is usually observed during a single displacement reaction is the release of heat and this shows the reaction is an exothermic reaction.