I think the correct answer from the choices listed above is option B. The reactants calcium sulfide and sodium sulfate will react and form a precipitate which is calcium sulfate since it is only slightly soluble in aqueous solution. Hope this answers the question.
D will be the answer I hope that help good luck I hope. My answer help you
Answer: 
Explanation: 1 gram is equal to 1000 Milligrams so
Since you go straight across its just multiplication so 0.00200x1000=200mg
To answer it in scientific notation it should just be mg
Answer:
0.1 L
Explanation:
divide the volume value by 1000
8) The gravitational force is a force of attraction between two objects. It can be expressed mathematically as:
F = G m₁*m₂/d² ------(1)
m₁ and m₂ are the masses of two interacting systems
d = distance between them
G = gravitational constant
Thus according to equation(1), the gravitational force is directly proportional to the mass of the objects. Greater the masses, stronger will be the force of attraction.
In this case, the distance (d) and the one of the masses i.e. mass of earth would be the same for both situations. However, since an elephant would weigh more than a human, the gravitational force will be stronger between an elephant and earth.
9) Since the masses of spheres is the same, the gravitational force between the red and blue spheres would be the same as well, provided the distance d remains constant.
