Answer:
D. all atoms with an atomic number over 83
If it is average speed per hour, then you just have to divide 3.5 into 60
60/3.5 = 17.143 so around 17km/h
When she releases the ball, it has some of both. (C)
Answer:
per mole of pentane = 3157.53 kJ/mol
Explanation:
Given:
Mass of pentane, m = 0.468 gram
Molar mass of pentane, M = 72.15
Now, mol of pentane, n = mass/M = 0.468/72.15 = 0.00648 mol of C5H12
Now,
ΔT = 23.65 - 20.45 = 3.2°C
Heat capacity of the calorimeter, C = 2.21 kJ/°C
Specific heat capacity of the water, Cp = 4.184 J/g.°C
Now,
the heat gained = the heat lost

also,


or

and
Now,

we have,
(Here negative sign depicts the release of the heat)
per mole of pentane =-20460.8/(0.00648 ) = 3157.53 kJ/mol