Answer:
1/16 is the answer.........
To do this problem, we must first look at the balanced chemical equation for the decomposition of potassium chlorate:
<span>2KClO3 --> 2KCl + 3O2 </span>
<span>We can take the given amount of grams, and use the molar mass of KClO3 to convert to moles. Then, we can use the stoichiometric ratios to relate moles of KClO3 to moles of O2. </span>
<span>(39.09)+(35.45)+(3*15.99)= 122.51 g/ mol = molar mass of KClO3 </span>
<span>45.8 g KClO3/ 122.51 g/ mol KClO3 = .374 moles KClO3 </span>
<span>.374 mol KClO3 *(3 moles O2/2 mol KClO3)= .560 moles O2 </span>
<span>Once we have moles of O2, we can convert to grams of O2. </span>
<span>(2*15.99)= 31.98 g/mol = molar mass of O2 </span>
<span>(.560 moles O2) (31.98 g/mol)= 17.91 g O2 </span>
<span>Hope this helps :)</span>
It would be the controlled variable, which is a baseline to compare your other variables too.
Hope this helps!
Since the teacher has said to use quantitative observation, density is the easiest measurement to make. Aluminum has a density of 2.7 g/mL. Brass has a density of 8.73 g/mL. Copper has a density of 8.96 g/mL. As long as the mass and volume measurements are accurate (water displacement can be used for volume measurements), the resulting density values can be distinguished.
It may be possible to distinguish these three metals visually, based on color, but the instructions have stated to use quantitative observation.
