Which type of force does a window washer want acting on him when trying to keep the same position

When the following equation is balanced using the smallest possible integers, what is the coefficent of oxygen gas? c7h16o(g) + o2(g) → co2(g) + h2o(g) -1 -5 -8 -16 -21

There are main groups in the modern periodic table of elements

Can someone me with 3 and 4 plz. this is for masteries test.