Explanation:
1 Cal of energy is equivalent to 4.184 Joules.
A.
770Cal of energy = 3221.680 joules
Therefore, 780kCal of energy = 3221680 Joules.
B.
3200000 Joules (in 2 s.f).
C.
I000 joules = 1 kJoule
3221680 joules = 3221.689 kJoules.
D.
3200 kJ (in 2 s.f).
Answer:
1.56 g of water was involved in the reaction
Explanation:
From the stoichiometric equation
2Na + 2H2O = 2NaOH + H2
NB : Mm Na= 23, Mm H2O = ( 2+16)= 18
2(23) of Na requires 2(18) of water
Hence 1.99g of Na will require 1.99×2×18/2(23) of water = 1.56 g of water
The answer is: " S²⁻ " .
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Answer:
option C is correct (250 g)
Explanation:
Given data:
Half life of carbon-14 = 5700 years
Total amount of sample = 1000 g
Sample left after 11,400 years = ?
Solution:
First of all we will calculate the number of half lives passes during 11,400 years.
Number of half lives = time elapsed/ half life
Number of half lives = 11,400 years/5700 years
Number of half lives = 2
Now we will calculate the amount left.
At time zero = 1000 g
At first half life = 1000 g/2 = 500 g
At second half life = 500 g/2 = 250 g
Thus, option C is correct.
Answer:
Radiation is being released from the reactor.
Explanation:
( A P E X )
