To measure a vector is to characterize both its direction (in one form or another) and a value (usually, a number). For example, velocity of a car moving on the road is a vector and, to measure it, we have to specify its direction (e.g. North or at angle 20 degrees from the North) and value (e.g. 40 m/sec).
<span>Answer:
Q = 500.0 x 4.18 x 8.63 = 18037 J => 18.037 kJ
moles anthracene = 0.455 g/ 178.234 g/mol=0.00255
0.00255 moles give 18.037 kJ
0.00255 : 18.037 = 1 mole : x
x = 7073 kJ/mol
enthalpy = - 70.73 kJ/mol</span>
Heat energy can be calculated by using the specific heat of a substance multiplying it to the mass of the sample and the change in temperature. It is expressed as:
<span>
Energy = mCΔT
</span><span>Energy = 132 (0.385) (45 - 32.2)
</span><span>Energy = 650.50 J</span>
Cutting of Nails is a Physical Change since no new substance is formed.
Don't confuse it with Reversible and Irreversible Changes
Answer: Divide the mass of the object by its volume to yield the density of the object. For example, the object density = mass / (Vf – Vi). Compare the measured density to that of pure gold (19.3 g/cc) to determine whether the object is made of pure gold.
Explanation: I searched it
