Answer:
The change in internal energy is - 1.19 kJ
Explanation:
<u>Step 1:</u> Data given
Heat released = 3.5 kJ
Volume calorimeter = 0.200 L
Heat release results in a 7.32 °C
Temperature rise for the next experiment = 2.49 °C
<u>Step 2:</u> Calculate Ccalorimeter
Qcal = ccal * ΔT ⇒ 3.50 kJ = Ccal *7.32 °C
Ccal = 3.50 kJ /7.32 °C = 0.478 kJ/°C
<u>Step 3:</u> Calculate energy released
Qcal = 0.478 kJ/°C *2.49 °C = 1.19 kJ
<u>Step 4:</u> Calculate change in internal energy
ΔU = Q + W W = 0 (no expansion)
Qreac = -Qcal = - 1.19 kJ
ΔU = - 1.19 kJ
The change in internal energy is - 1.19 kJ
They are all pentoses. In their linear forms, they all contain carbon carboxyl and several hydroxyl functional groups. In their linear forms, they all contain a carbonyl and several hydroxyl functional groups.
Carbon is a chemical element with the symbol C and atomic number 6. Carbon is a non-metal and is tetravalent. That atom donates four electrons to form a covalent chemical bond. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025% of the Earth's crust.
Carbon is used in some form in almost every industry in the world. It is used as fuel in the form of coal, methane gas, and crude oil (used to make gasoline). It is used to make all sorts of materials, including plastics and alloys such as steel (a combination of carbon and iron). Carbon is also found in fossil fuels such as petroleum (crude oil), coal and natural gas. Carbon is also found in dead, decaying animals and animal waste soils. Carbon is stored in the biosphere of plants and trees.
Learn more about carbon here
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Answer:
19,700 Joules
Explanation:
Quantity of heat (Q) = mc(T2-T1)
m (mass of ethanol) = 183g
c (specific heat capacity of ethanol) = 2.44J/g°C
T2 (boiling temperature of ethanol) = 78°C
T1 (initial temperature of ethanol) = 33.9°C
Q = 183×2.44(78 - 33.9) = 183×2.44×44.1 = 19691.532 = 19,700 Joules (to three significant digits)
The mantle has a mass of around
that is around 68.4% of earth's mass.
So to calculate moles we need to first find out the mass of oxygen and silicon present in mantle. It is given that oxygen is 44.8% by mass in mantle and 21.5% by mass in mantle, therefore to calculate its mass, we need to use 
Now, to calculate mass percentage of oxygen


Similarly the mass of silicon can be calculated

Now, the moles of any substance is calculated by


where, mass of oxygen in kilograms is 
So,
Similarly 

Now, to calculate mole ratio we need to divide every moles to the lowest calculated mole that is the moles of Si and round it off to the nearest whole number.




