Remember: energy is conserved in a chemical reaction (visualize the reaction and question whether heat lies on reactant side (left) or product side (right))
-exothermic- heat is released (heat is on the product side)
>forming an ionic lattice (SALT)- mixture of Na and Cl results in a more stable ionic lattice, causing this reaction to be exothermic
>burning wood
-endothermic- heat is absorbed (heat is on the reactant side)
> cooking an egg
Answer:
THE MOLARITY OF SODIUM CHLORIDE IN THE CONTAINER IS 0.3846 M.
Explanation:
Molarity of a solution is the number of moles of solute per dm3 of solution.
Mass concentration = Molar concentration * Molar mass
1. calculate the mass concentration;
Mass conc. = 45 g in 2 L
= 45 g in 2 dm3
In 1 dm3, the mass will be 45 / 2
= 22.5 g/dm3 of NaCl.
2. Calculate the molar mass;
(Na = 23, Cl = 35.5)
Molar mass = ( 23 + 35.5 ) g/mol
Molar mass = 58.5 g/mol
3. calculate the molarity
Molarity = mss concentration / molar mass
Molarity = 22.5 g/dm3 / 58.5 g/mol
Molarity = 0.3846 mol/dm3 of NaCl.
The molarity of sodium chloride in the container is 0.3846 mol/dm3
<span> they are known as spermatophytes</span>
