Answer:
10
x
^3
−
10
x
^2
+
10
x
−
12
Explanation:

The chemical property deals with the ability of a substance being able to burn is called combustibility [ option b ] .
<u>More</u><u> to</u><u> know</u><u> </u><u>:</u><u>-</u>
<em>1</em><em>)</em><em> </em><em>Combustion</em><em> </em><em>:</em><em>-</em>
Combustion is a chemical process in which a substance reacts rapidly with oxygen and gives out heat.
The fuel can be any one of the 3 states of matter that is - solid , liquid & gases .
Examples of combustible substances :-
Solid - Coal
Liquid - Petrol , Disel , etc.
Gas - Hydrogen , Oxygen , etc .
Answer:
mass (m) of the snow that the backpacker collected= 0.855 kg
Explanation:
Given that:
Q = 643 kJ = 643000 J
ΔHfusion = 6.02 kJ/mol = 6020 J/mol
number of mole of water H2O = 
c = 4.18 J/g⋅K
ΔT = 100 K
Since there is a phase change from solid to liquid; then :

ΔH = 
However without the given mass; we substitute
for the number of moles; so:
Q =



m = 855 g
m = 0.855 kg
mass (m) of the snow that the backpacker collected= 0.855 kg
Explanation:
I'll give you a real answer later need points for test questions sorry
Answer: C. ethanol
The enthalpy of combustion is the amount of heat produced when one mole of ethanol undergoes complete combustion at 25 ° C and 1 atmosphere pressure, yielding products also at 25 ° C and 1 atm.
<u>The enthalpy of combustion of the unknown compound is</u>
ΔH = - 320 kJ / 0.25 mol = - 1280 kJ / mol
<u>To choose a probable compound according to this combustion enthalpy, we must evaluate the deviation in relation to the values reported in the literature for the three probable compounds</u> (methane, ethylene and ethanol). The deviation (e%) will be calculated according to the following equation,
e% = ( | ΔHx - ΔH | / ΔHx ) x 100%
where ΔHx is the enthalpy of combustion of the probable compound.
The following table shows the combustion enthalpies of the probable compounds and their deviation in relation to the enthalpy of ΔH = - 1280 kJ / mol
Compound Enthalpy of combustion (kJ/mol) Deviation
Methane - 890.7 43.8%
Ehylene -1411.2 9.3%
Ethanol -1368.6 6.5%
According to the previous table, we can say that the most probable compound is ethanol, since it has the smallest deviation in relation to the experimental enthalpy value of combustion.