Answer:
1.07 g
Explanation:
Half-life of Pu-234 = 4.98 hours
Initially present = 45 g
mass remains after 27 hours = ?
Solution:
Formula
mass remains = 1/ 2ⁿ (original mass) ……… (1)
Where “n” is the number of half lives
To find "n" for 27 hours
n = time passed / half-life . . . . . . . .(2)
put values in equation 2
n = 27 hr / 4.98 hr
n = 5.4
Mass after 27 hr
Put values in equation 1
mass remains = 1/ 2ⁿ (original mass)
mass remains = 1/ 2^5.4 (45 g)
mass remains = 1/ 42.2 (45 g)
mass remains = 0.0237 x 45 g
mass remains = 1.07 g
Answer:
Explanation:
Al (s) + CuSO4 (aq) → Cu (s) + Al2(SO4)3 (aq)
2Al (s) + 3CuSO4 (aq) → 3Cu (s) + Al2(SO4)3 (aq).
is the balance chemical equation
Answer is: the specific heat capacity of the metal is <span>A) 0.129 J/gK.
</span>m(metal) = 15,1 g.
Q = 48,75 J.
ΔT = 25 K.
Q = C · ΔT · m(metal).
C = Q ÷ ΔT · m(metal).
C = 48,75 J ÷ 25 K · 15,1 g.
C = 0,129 J/g·K.
Answer:
W = -10.3 kJ
Explanation:
During combustion, the system performs work and releases heat. Therefore, the change in internal energy is negative, and the change in enthalpy, which is equal to heat at constant pressure, is also negative. Work is then calculated by rearranging the equation for the change in internal energy:
w=ΔE−qp=−5084.3 kJ−(−5074.0 kJ)
The release of heat is much greater than the work performed by the system on its surroundings. The potential energy stored in the bonds of octane explains why considerably large amounts of energy can be lost by the system during combustion.
Answer:
Explanation:
Mass percent is defined as the mass of an element divided by the sum of masses of all the elements multiplied by 100. It is generally used to define the concentration. It does not depend on concentration.
It is given as;
Mass percent = (mass of an element / Total mass of the compound ) × 100
Mass of compound (alloy) = 78.2 g copper + 103.5 g zinc +2.8 g lead = 184.5 g
(a) Cu
Mass of Cu = 78.2
Mass percent = (78.2 / 184.5) * 100 = 42.38%
(a) Zn
Mass of Zn = 103.5
Mass percent = (103.5 / 184.5) * 100 = 56.10%
(c) Pb
Mass of Pb = 2.8
Mass percent = (2.8 / 184.5) * 100 = 1.52%
