1 m = 0,001 km
1m³ = 0,000000001 km³
278 m³ = 0,000000278 km³ = 2,78×10^(-7) km³
:•)
Answer:
The balance chemical equation can be given as:

Explanation:
When zinc sulfide is allowed to react with zinc sulfate it gives zinc metal and sulfur dioxide gas as a product.The balance chemical equation can be given as:

According to reaction we can see when 1 mol of zinc sulfide reacts with 1 mol of zinc sulfate it forms 2 moles of zinc metal and 2 moles of sulfur dioxide gas.
A drop of iquid mercury is D. <span> a pure substance and an element. This is because mercury is an element which exists as liquid in the normal or standard conditions. It is a metal that is toxic to all environments. It is pure because it is composed only of one kind of substance.</span>
The dissociation of isocyanic acid in water produces its conjugate base, C N- since it will accept a proton to form isocyanic acid.
<h3>What is a conjugate base?</h3>
A conjugate base is a substance which is formed from the loss of the hydrogen ion of an acid and which will act as a base by accepting a proton.
The dissociation of Isocyanic acid in water is given below:

The conjugate base is C N- since it will accept a proton to form isocyanic acid.
Learn more about conjugate base at: brainly.com/question/22514615
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