Answer:
2. Copper (II) carbonate plus sulfuric acid produces copper (II) sulfate and carbon dioxide and water.
- We need the "II" after copper to specify what charge it is. It's +2 because carbonate is -2.
3. Calcium hydroxide plus carbon dioxide gas produces calcium carbonate and water.
Mass of the steel is 
- density of a substance can be regarded as the ratio of the mass of that substance to that of it's volume.
- Mass of substance can be regarded as the quantitative measure of inertia, it can be simply explained as a fundamental property of all matter
<em> We can express this mathematically as ;</em>
Given :
Density of this steel= 8.1g/cm3

If we make Mass subject of formula,

Then let us substitute the values into the expression

Therefore, mass of the steel is 
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Answer:
Sulfur reacts with oxygen to form sulfur dioxide. When nonmetals reactwith one another, the product is a molecular compound. Often, the nonmetal reactants can combine in different ratios and produce different products. Sulfur can also combine with oxygen to produce sulfur trioxide.
<span>B. S⁰(s) + 2H⁺ + 2e⁻ –--> H2S⁰(g)
by mass: 1 S and 2 H ----> 2 H and 1S True.
by charge : 0 +(2*(+1)) + 2*(-1) = 0, 0+2-2=0, 0 = 0 True.</span>
1 valence electron in alkali metals.