Answer:
Answer: The mass of product left in the test tube will be less than the initial measured mass of the reactants.
Explanation: This is because one of the products of the reaction is a gas (hydrogen) and it escapes as the reaction happens in an open system.
This is the reaction,
Mg(s) + 2HCl(aq) --------> MgCl2(aq) + H2(g)
So, evidently, only MgCl2 is left in the reaction test tube together with unreacted reactants.
But, the hydrogen gas that escapes accounts for the lesser mass at the end of the reaction.
The mass in the test tube at the end of the reaction +
the mass of Hydrogen gas that escapes = the mass of reactants before the reaction; consolidating the law of conservation of mass.
Answer:
4.3 x 10(d) J
Q= 400 x 45 x 0.233 = 4.419 kj
Explanation:
Not sure if this is what your looking for... hope it helps though :)
Answer:
Both molarity and molality involves number of moles of solute
Explanation:
Molarity is obtained by dividing the number of moles of solute by the volume of solution in liters. Note that a solution is formed when a solute is dissolved in a given volume of solvent.
Molality, of a solution is obtained by dividing the number of moles of a solute by the number of kilogrammes of solvent.
In both cases, the number of moles of solute is involved. Hence, the number of moles of solute present is common to both molarity and molality calculation.
Answer:
2.843 M
Explanation:
Molarity = moles / volume
<u>Milliliters to liters:</u>
500 mL <u>= .500 L</u>
<u>Grams to moles:</u>
MgO molar mass = 16.00 + 24.31 = 40.31 g/mol
57.3 g x 1 mol / 40.31 g = <u>1.421 mol</u>
<u>Molarity:</u>
1.421 mol / .500 L = 2.843 M