In a chemical reaction, reactants that are not used up when the reaction is finished are called excess reagents. The reagent that is completely used up or reacted is called the limiting reagent, because its quantity limits the amount of products formed. The limiting reactant or limiting reagent is the first reactant to get used up in a chemical reaction. Once the limiting reactant gets used up, the reaction has to stop and cannot continue and there is extra of the other reactants left over. Those are called the excess reactants. The reactant that produces a lesser amount of product is the limiting reagent. The reactant that produces a larger amount of product is the excess reagent. To find the amount of remaining excess reactant, subtract the mass of excess reagent consumed from the total mass of excess reagent given.
Answer:
c. H₂O (l) → H₂O(s)
Explanation:
The correct answer is option C: The molecular formulas for the substance(s) on the left side of the equation and on the right side of the equation are identical. This means that there was not a chemical change, but a physical one.
In this concrete example, what happened was a <em>change of states of matter</em>: from liquid (l) to solid (s).
Other reactions have different molecular formulas on both sides of the equation, thus they represent chemical changes.
When there is a transfer of heat a wind usually blows from where the heat is transferred from
Answer:
alkyl halide + 2 (ammonia) → alkyl amine + ammonium halide
Explanation:
In this type of preparation of alkyl amine this process works through substitution nucleophilic second order reaction and the nucleophile in this case is the ammonia and the leaving group will be the chloride ion
When ammonia attacks opposite to the way in which leaving group leaves, the chloride ion will be leaved and the nitrogen attains positive charge
So one of the hydrogen attached to the nitrogen will be removed and as there is another mole of ammonia and as ammonia is a base, it takes that hydrogen and it will form ammonium ion and to this ion chloride ion will get attracted as both have opposite charges and at last alkyl amine and ammonium halide will be formed
<span>(A) Cell walls have gap junctions. Cell membranes have plasmodesmata.
</span>