Which of the following is not a statement of Dalton's atomic theory of matter?a. Elements are made of atomsb. Atoms of a given e
1 answer:
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Answer:
The heat required to raise the temperature of 12g of water from 16 C to 21 C is 60 cal.
Explanation:
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.
There is a direct proportional relationship between heat and temperature. The constant of proportionality depends on the substance that constitutes the body as on its mass, and is the product of the specific heat by the mass of the body. So, the equation that allows calculating heat exchanges is:
Q = c * m * ΔT
where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.
In this case, you know:
- Q=?
- c= 4.186
- m= 12 g
- ΔT=Tfinal - Tinitial= 21 °C - 16°C= 5 °C
Replacing:
Q= 4.186 *12 g *5 °C
Solving:
Q=251.16 J
Since 1 J is equal to 0.2388 cal, then the following rule of three can be applied: if 1 J is equal to 0.2388 cal, then 251.16 J to how many cal are?
cal= 59.98 ≅ 60
<u><em>The heat required to raise the temperature of 12g of water from 16 C to 21 C is 60 cal.</em></u>
Explanation:
In order to find the molecular formula, we have to find the empirical formula first of all.
It is known that is a styrofoam, elements present are carbon and hydrogen atoms.
Element % Atomic mass Molar ratio Simple ratio
C 92.25 12.01 = 7.68
= 1
H 7.75 1.008 = 7.68
= 1
As empirical formula of styrofoam is C_{x}H_{x}.
Hence, empirical mass = (12.01 + 1.008) g/mol = 13.018 g/mol = 13.0 g/mol (approx)
Molar mass given is 104 g/mol.
So, =
= 8
Thus, we can conclude that molecular formula of the given styrene is .