The answer is 3. The releasing of energy means exothermic reaction. So the ΔH should be negative. And the greatest quantity of energy released means that the greatest number. So according to the table I, the answer is 3.
Answer:
Chemical Change
Explanation:
chemical bonds within the substance have been altered because a new substance has been produced. It cannot be a mixture because they do not involve changes in matter, it cannot be a physical change because they do not result in new substances, it is not a solution because those do not involve changes in matter.
They should report the density as 1.11 g/L
.
Density = mass/volume = 2.260g/2.04 mL
My calculator says the density <em>1.107 843 137 g/mL</em>
However, the answer can have <em>no more</em> significant figures than are in the number with the <em>fewest </em>significant figures.
The volume measurement has only three significant figures, so we must round off the density to three significant figures.
We drop all the digits after the zero.
The digit to be dropped is 7, so we <em>round up </em>the last significant figure of the answer.
1.10<u>7 843 137</u> → 1.11
Answer:
0.453 moles
Explanation:
The balanced equation for the reaction is:
2Fe(s) + 3O2(g) ==> 2Fe2O3
From the equation, mass of O2 involved = 16 x 2 x 3 = 96g
mass of Fe2O3 involved = [(2x26) + 3 x 16] x 2
= 100g
Therefore 96g of O2 produced 100g of Fe2O3
32.2g of O2 Will produce 100x32.2/96
= 33.54g of Fe2O3
Converting it to mole using number of mole = mass/molar mass
but molar mass of Fe2O3 = 26 + (16 X 3)
= 74g/mole
Therefore number of mole of 33.54g of Fe2O3 = 33.54/74
= 0.453 moles
