454 teraHz I think, tell me if this is wrong
Answer:
D. 2.5 × 10–4 M
Explanation:
Data given in the question are;
rate constant of 5.0 × 10–2 mol/L·s
[A]0 = 1.0 × 10–3 M
5 × 10–3 sec
It was mentioned that the reaction is a zero order reaction. One interesting charaacteristics about zero order reactio is that the rate of reaction is indepenedent on the concentrations of the reactants.
This means in zero order reactions, we have;
Rate = Rate constant
Rate = 5.0 × 10–2 mol/L·s
What is the concentration of B after 5 × 10–3 sec?
Concentration = Rate * Time
Concentration = 5.0 × 10–2 * 5 × 10–3
Concentration = 2.5 × 10–4 M
Correct option = D
f it is solid iron, use the density to get the mass. D x V = mass
Use the mass to find the moles of Fe. Mass/atomic mass = moles
Moles x Avogadro's number will give you the particles, assuming that you mean atoms.
Answer:
Q = 270 Joules (2 sig. figs. as based on temperature change.)
Explanation:
Heat Transfer Equation of pure condensed phase substance => Q = mcΔT
Mixed phase (s ⇄ l melting/freezing, or l ⇄ g boiling/condensation) heat transfer equation => Q = m∙ΔHₓ; ΔHₓ = phase transition constant
Since this is a pure condensed phase (or, single phase) form of lead (Pb°(s)) and not melting/freezing or boiling/condensation, one should use
Q = m·c·ΔT
m = mass of lead = 35.0g
c = specific heat of lead = 0.16J/g°C
ΔT = Temp change = 74°C - 25°C = 49°C
Q = (35.0g)(0.16J/g·°C )(49°C) = 274.4 Joules ≅ 270 Joules (2 sig. figs. as based on temperature change.)
Answer:
Explanation:
Mg + 2HCl = Mg Cl₂ + H₂
.594 g = .594 / 24.3
= .02444 mole
Heat evolved = msΔ T , m is mass of water ( solvant ) , s is specific heat of water , Δ T is rise in temperature
= 100 x 4.2 x ( 41.83 - 25 )
= 7068.6 J
.02444 mole of Mg evolves 7068.6 J of heat
1 mole of Mg evolves 7068.6 /.02444 J
= 289222.6 J
= 289 kJ .
Molar heat enthalpy = 289 kJ .
