Consider the following equation for the combustion of acetone (C3H6O), the main ingredient in nail polish remover. C3H6O(l) + 4O2(g) → 3CO2(g) + 3H2O(g) ΔHrxn = −1790kJ
If a bottle of nail polish remover contains 143 g of acetone, how much heat would be released by its complete combustion? Express your answer to three significant figures.

a) 4869 kj will be released

b) 43.86 g of octane

Explanation:

The heat of combustion is the amount of heat released when one mole of a substance reacts with enough oxygen

since the heat of combustion is per mol of combustible substancewjat we are required to do in this problem is calculate number moles in the reactions although in a different manner

a) MW C3H6O = 158 g/ mol

mol C3H6O = 158 g × 1 mol/ 58.08 g

= 2.72 - 1790 kj / mol ×2.72 mol = 4869 kj

b) Here we are asked the mass of octane to produce 1950 kj of heat knowing that per mole of octane we get 5074.1 kj then

1 mol / 5074.1kj × 1950 kj= 0.384 mol

mass C8H18 = 0.384 mol × 114.23 g/ mol = 43.86 g

The density of acetone is 0.788 g/mL.

the answer would be c

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.