The answer to this question is A
Answer:
D. chemical alters the atomic structure of a substance, while physical does not
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Answer:
When a Magnesium Ribbon is burnt, a powdery substance called magnesium oxide is formed.
Explanation:
There has obviously been a chemical change because several chemical properties of the magnesium have been modified: the color, the texture and the mass.
The increase in mass is due to the fact that oxygen from the air has combined with the magnesium to make magnesium oxide, MgO.
The chemical equation, Mg + O2 MgO shows this reaction but it needs to be balanced to make 2Mg + O2 2MgO.
Using stoichiometry, we can convert this eqation into an equation with moles:
2 mol Mg + 1 mol O2 2 mol MgO.
Next, we convert to grams using atomic masses obtained from the periodic table:
48g Mg + 32g O2 80g MgO
Lastly, we determine the same thing in the proportions we used. In other words, we used only 0.15g of Mg (not 48g) so everything needs to be divided by 320. So 80 / 320 = 0.25 g. If we burn 0.15 g of Mg, we obtain 0.25 g of MgO.
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This is my first answer.
<span>The question says,'which statement best describes how an ionic bond forms. The correct option is A. Ionic bonds are formed as a result of complete transfer of electrovalence electrons from one atom to another. The atom that donate the electron become a positively charged ion while the atom that received the atom become a negatively charged ion.</span>
The answer should be 2KI(aq)+Hg(NO3)2(aq) = 2KNO3(aq) + HgI2(s). This is a double replacement reaction, the valence of elements will not change. The HgI2 is not soluble in water.
