Answer: The correct option is C ( is very hard and burns cleanly).
Explanation:
COAL is a form of rock that is made up of mostly carbon amongst other elements which includes sulphur, nitrogen, hydrogen and oxygen. There are different types of coal which include:
--> anthracite ( 90% carbon)
--> bituminous coal ( 70-90% carbon)
--> lignite ( 60- 70% carbon) and
--> peat (60 % carbon).
Anthracite is the type of coal that contains the highest carbon content ( 90% carbon). This makes it very hard and is often a times referred to as HARD COAL. Anthracite is a higher quality coal for domestic and open fire heating. This is because it contains less impurities than other type of coal and thereby making it to BURN CLEANLY avoiding atmospheric pollution.
Answer:
The behavior of molecules in different phases of matter represents a balance between the kinetic energies of the molecules and the attractive forces between them. All molecules are attracted to each other. The molecules are in the solid-state. At higher temperatures, the kinetic energy of the molecules is higher.
Answer:
A sample of an ideal gas has a volume of 2.21 L at 279 K and 1.01 atm. Calculate the pressure when the volume is 1.23 L and the temperature is 299 K.
You need to apply the ideal gas law PV=nRT
You have the pressure, P=1.01 atm
you have the volume, V = 2.21 L
The ideal gas constant R= 0.08205 L. atm/ mole.K at 273 K
find n = PV/RT = (1.01 atm x 2.21 L / 0.08205 L.atm/ mole.K x 273 K)
n= 0.1 mole, Now find the pressure for n=0.1 mole, T= 299K and
L=1.23 L
P=nRT/V= 0.1mole x 0.08205 (L.atm/ mole.K x 299 k)/ 1.23 L
= 1.994 atm
Explanation:
Answer: The frequency of this light is 
Explanation:
To calculate the wavelength of light, we use the equation:

where,
= wavelength of the light =
c = speed of light = 
= frequency of light = ?

The frequency of this light is 
Distance = 1500m, time = 14min 34.56s = 14*60 + 34.56 = 874.56s
Speed = Distance / time = 1500/874.56 = 1.715 m/s
In order to swim 0.7 miles, 1 mile = 1609.344 m
Time = Distance / speed = 1609.344 m / 1.715 m/s = 938.393 seconds
938/60 = 15 minutes, 38 seconds.
= 15 minutes 38.393 seconds.