The top number on elements in the periodic table is the atomic number, so when you look at the periodic table you can see that 42 is Mo (Molybdenum), and this is the only element with that atomic number.
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-2.5089 kJ is the amount of heat is released by the combustion of the naphthalene.
<h3>How we calculate the released heat?</h3>
Released amount of heat is calculated by using the below formula:
Q = -mcΔT, where
m = mass of naphthalene = 0.25g
c = specific heat of calorimeter = 4.13 kJ/°C
ΔT = change in temperature = 26.43°C - 24°C = 2.43°C
Putting all these values in the above equation, we get
Q = - (0.25 × 4.13 × 2.43) = - 2.5089 kJ
Hence, - 2.5089 kJ heat is released.
To know more about released heat, visit the below link:
brainly.com/question/13439286
Answer:
Almost 3 snicker's bar will contain the worth of energy stored in the battery which makes option A correct (Fewer than 5)
Explanation:
Step 1
The energy stored in a charged battery is 840 Watt- hours
Recall from the question that 1 KWh = 3600 KJ
So how many Kilo-joules will be in 840 Watt- hours?
I will convert 840 Watt- hours to KWh = 840 / 1000
= 0.840 KWh
Since I KWh gives 3600 KJ
then, 0.840 KWh will give x
x = 3024 KJ
3024 KJ of energy is stored in the battery
Step 2
A snicker bar contains 250 cal and 1 cal = 4.184 KJ
Convert 250 cal to KJ?
250 cal = 1046 KJ
Each snicker bar contains 1046 KJ
To calculate how many snicker's bar worth energy stored in the battery will be (y) ?
y = 3024 / 1046
y = 2.9 snicker's bar approximately 3
The correct option is Fewer than 5
