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What are the numbers that must be placed in the blank to balance the chemical equation?
SO2 + ___ H2 > S + H2O
1,2,1,2
2,1,1,2
2,1,2,1
1,2,2,1

What is true of both gravity and magnetism?

Both are dependent on mass.
Both forces can act without objects touching.
Both forces are directly proportional to the distance between the objects.
Neither is a fundamental force of nature.

What is true of both light and sound?

They are both transverse waves.
They can both travel through the vacuum of space.
Both can be modeled as waves having amplitude, frequency and wave lengths.
They both move at the same speed.

When the motion energy of an object changes, there is inevitably some other change in energy at the same time. If an object is slowing down, where is the energy going? (Check all that apply)

The potential energy could be increasing, like a ball thrown into the air.
The kinetic energy could be lost to friction or air resistance.
The ball could be returning to its natural resting state.
Due to the conservation of energy, the kinetic energy must stay the same.

1.) A - 1,2,1,2

2.) Both forces can act without objects touching.

3.) C

Both can be modeled as waves having amplitude, frequency and wave lengths.

4.) A, B and C

Explanation:

1.) SO2 + ___ H2 > S + H2O

Looking at above equation, we have one molecule of surfur at the right hand side (RHS), and one molecule of surfur at the left hand side (LHS).

Two atoms of hydrogen and both RHS and LHS

But oxygen is not balanced. We have two atoms of oxygen at the RHS while having one at the LHS.

So let's make oxygen 2 atoms at LHS by adding 2 to water molecules and hydrogen molecules at the RHS.

SO2 + ___ 2H2 > S + 2H2O

The correct answer is A - 1,2,1,2

2.) Both magnetic force and gravitational force obey inverse square law with distance. They are not directly proportional but inversely proportional to the square distance. B is the correct answer because Both forces can act without objects touching.

3.) Light waves are transverse waves which can travel through a vacuum without a medium while sound waves are longitudinal waves which cannot travel through vacuum without a medium. But both can be modeled as waves having amplitude, frequency and wave lengths.

4.) If an object is slowing down, due to conservation of energy,

The potential energy could be increasing, like a ball thrown into the air.

The kinetic energy could be lost to friction or air resistance.

The ball could be returning to its natural resting state.

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form