Substances that are good conductors of heat and electricity at room temperature usually

Combustion analysis of toluene, a common organic solvent, gives 5.27 mg of co2 and 1.23 mg of h2o. if the compound contains only

kherson [118]

C7H8 First, determine the number of relative moles of each element we have and the molar masses of the products. atomic mass of carbon = 12.0107 atomic mass of hydrogen = 1.00794 atomic mass of oxygen = 15.999 Molar mass of CO2 = 12.0107 + 2 * 15.999 = 44.0087 Molar mass of H2O = 2 * 1.00794 + 15.999 = 18.01488 We have 5.27 mg of CO2, so 5.27 / 44.0087 = 0.119749 milli moles of CO2 And we have 1.23 mg of H2O, so 1.23 / 18.01488 = 0.068277 milli moles of H2O Since there's 1 carbon atom per CO2 molecule, we have 0.119749 milli moles of carbon. Since there's 2 hydrogen atoms per H2O molecules, we have 2 * 0.068277 = 0.136554 milli moles of hydrogen atoms. Now we need to find a simple integer ratio that's close to 0.119749 / 0.136554 = 0.876937 Looking at all fractions n/m where n ranges from 1 to 10 and m ranges from 1 to 10, I find a closest match at 7/8 = 0.875 with an error of only 0.001937, the next closest match has an error over 6 times larger. So let's go with the 7/8 ratio. The numerator in the ratio was for carbon atoms, and the denominator was for hydrogen. So the empirical formula for toluene is C7H8.

4 0

3 years ago

Which elements in the periodic table are metalloids or have semimetallic properties?

inessss [21]

B, As only are metalloids or have semimetallic properties.

3 0

2 years ago

What is the formula for calcium chloride? Ca2Cl CaCl CaCl2 CaCl3

djyliett [7]

Hello there, and thank you for asking your question here on brainly.

The answer to this is Answer choice C: CaCl2

Hope this helped you! ♥

8 0

3 years ago

Read 2 more answers

Stearic acid (C18H36O2) is a fatty acid, a molecule with a long hydrocarbon chain and an organic acid group (COOH) at the end. I

Paha777 [63]

Answer:

There is 9671 Kj of heat released

Explanation:

Step 1: The balanced equation:

C18H36O2(s) + 26O2(g) --> 18CO2(g)+18H2O(g)

This means for 1 mole of C18H36O2 consumed there is 26 moles of O2 needed to produce 18 moles of CO2 and 18 moles of H2O.

Step 2: Calculate the heat of combustion

ΔH (combustion) = [18*(ΔHf of CO2) + 18*(ΔHf of H2O)] - [1*(ΔHf of C18H36O2) + 26*(ΔHf of O2)]

ΔH (combustion) = [18*(-394 kJ/mol) + 18*(-242 kJ/mol)] - [1*(-948 kJ/mol) + 26*(0 kJ/mol)]

ΔH (combustion) = [(-7092 kJ/mol) + (-4356 kJ/mol)] - (-948 kJ/mol)

= -10500 kJ/mol

ΔH (combustion) = heat released / number of moles of stearic acid

Step 3: Calculate moles of stearic acid

moles of stearic acid = mass / Molar mass of stearic acid

moles of stearic acid = 262g / 284.48 g/mole = 0.921 moles

Step 4: Calculate moles of oxygen

moles of O2 = 914.5 / 32g/mole

moles of O2 = 28.578125 moles

Stearic acid is the limiting reactant: it will completely react

There will react 26*0.921 mole = 23.946 mole of O2

This means there will remain 4.63 moles of O2

Step 5: Calculate heat released

q = (ΔH combustion) * (moles of stearic acid) = (-10500 kJ/mol) * (0.921 moles) = 9671 Kj

There is 9671 Kj of heat released

6 0

2 years ago

So i need answers. Take your time its alright im not going to push it out. Thanks!

kirill115 [55]

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

3 0

2 years ago