. Write a balanced equation for the combustion of propane,
C3H8
When balanced, the equation indicates
that moles of
O2 are required for each mole of C3Hg8

C3H8 + 5O2 = 3CO2 + 4H2O

Explanation:

1.  First start by writing out the unbalanced equation

2.  Count all the atoms on both sides of the equation

C = 3         C =1

H = 8         O=3

O = 2         H =1

3.   Start by balancing the carbon atoms. What would it take to have 3 Carbon atoms on the left? You would add a 3 in front of the carbon atoms on the left side to match the carbon atoms on the right.

4.   Now Try balancing the H atoms. You have 8 H atoms on the right and 1 H atom on the left. To balance these out you would need to add a 4 in front of the H atom which gives you 8 on both sides.

5.  Now balance out the oxygen atoms. Since we added coefficients to the compounds on the left we now have 10 oxygen on the left 4x1=4 + 3x2=6 now balance out the right side of the equation by adding a 5 in front of the O2 5x2 Oxygen gives you 10.

I hope this helps

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.