Answer:
59.89 KJ
Explanation:
Data Given:
mass of H₂O (m) = 26.5 g
heat released (Q) = ?
Solution:
This question is related to the latent heat of condensation.
Latent heat of condensation is the amount of heat released when water vapors condenses to liquid.
Formula used
Q = m x Lc . . . . . (1)
where
Lc = specific latent heat of condensation
Latent heat of vaporization of water is exactly equal to heat of condensation with -ve charge
So, Latent heat of vaporization of water has a constant value
Latent heat of vaporization of water = 2260 J/g
So
Latent heat of condensation of water will be = - 2260 J/g
Put values in eq. 1
Q = (26.5 g) x (- 2260 J/g)
Q = - 59890 J
convert J to kJ
1000 J = 1 KJ
59890 J = 59890 / 1000 = 59.89 KJ
So, 59.89 K of heat will be released. negative sign indicate release of energy for condensation
Answer:
3.3792 g
Explanation:
The balanced equation for the reaction is given as;
2 C2H2(g) + 3 O2(g) --> 2 CO2(g) + 2 H2O(g)
From the reaction;
2 mol of C2H2 requires 3 mol of O2
2.0 g of C2H2
Number of moles = Mass / Molar mass = 2 / 26.04 = 0.07680 mol
5.0 g of O2
Number of moles = Mass / Molar mass = 5 / 32 = 0.15625 mol
The limiting reactant is; C2H2
2 mol of C2H2 produces 2 mol of CO2
0.07680 mol produces x
Solving for x;
x = 0.07680 mol
Mass = Molar mass * Number of moles = 44 g/mol * 0.07680 mol = 3.3792 g
The object will speed up and start to spin in different directions.
Answer:
The correct answer is <u>Option</u><u>-</u><u>B</u> (Convert grams of Mg to moles)
Explanation:
In stoichiometry problems the first step is always to balance the given unbalanced chemical equation. In our case the given equation is already balanced hence, we looked for the second step.
As Niven wants to calculate the mass of MgO (which is the product) with respect to Mg (reactant) hence here comes another important rule. In such cases if one wants to compare masses of two reactants or reactant product. or product product then one should first convert the given mass into moles, also the same conversion for the second mass and then compare the moles and at last convert the moles back into mass. So, the flow chart should be like,
Mass (Mg) → Moles (Mg) : (MgO) Moles ← (MgO) Mass
After finding moles following step take place,
Moles (MgO) → Mass (MgO)