Answer:
B
Explanation:
the candle is hot so the first energy form should be heat. u could now just eliminate the rest but for further notice. the heat melts the wax in the candle, which is a physical change but also the thread is burning out which is a chemical change then light follows
Answer:
1
all matter is made of tiny particles called atom
Answer:
D
Explanation:
The amount of energy released or absorbed is equal the product of the mass, the specific heat capacity and the temperature change. The temperature change being the difference between the final and initial temperature.
Q = mc∆T
Q = heat energy (Joules, J) m = mass of a substance (kg) c = specific heat (units J/g∙K)
∆ is a symbol meaning "the change in" ∆T = change in temperature (Kelvins, K)
From the data provided in the question, we can deduce that:
Q = 16.7KJ = 16,700J
m = 225g
c = 1.74J/g.k
For the temperature, let the final temperature be f. This means our ∆T = f - 20
16,700 = 225 * 1.74 * (f - 20)
16700 = 391.5 (f - 20)
f - 20 = 16700/391.5
f - 20 = 42.7
f = 20 + 42.7 = 62.7
Using Avogadros number, we can get that 1 mole of an atom
contain 6.022 x 10^23 atoms. Therefore we can use this conversion factor to get
the number of moles:
moles ZnCO3 = 6.11 x 10^22 atoms * (1 mole / 6.022 x 10^23
atoms) = 0.10146 moles
The molar mass of ZnCO3 is about 125.39 g/mol, therefore the
mass is:
mass ZnCO3 = 0.10146 moles * (125.39 g / mol)
<span>mass ZnCO3 = 12.72 g</span>
