Answer:
a) Explain why:
(i) All the elements of a group have similar chemical properties.
(ii) All the elements of a period have different chemical properties.
(b) The atomic radii of three elements X, Y and Z of a period of the periodic table are 186 pm, 104 pm and 143 pm respectively. Giving a reason arrange these elements in the increasing order of atomic number in the period.
Explanation:
When designing and conducting a scientific experiment then it is necessary to sequentially follows all the steps necessary for the experiment.
Also, it is required to identify independent variables, if any. On the other hand, it is required to address any confounding variables, so that it becomes mentioned the type or number of variables present.
Thus, we can conclude that when designing and conducting a scientific experiment:
- Identify the independent variable.
- Address any confounding variables.
There are 4 different products will be formed from a poorly planned crossed aldol addition.
In a crossed aldol condensation, two distinct ketone and aldehyde reactants are used. Due to the possibility of several enolate nucleophiles as well as multiple carbonyl electrophiles, similar reactions typically result in a variety of distinct condensation products.
Ethanol and propanol undergo cross-aldol condensation, which results in two products:
- one where ethanol serves as an enolate ion and the other where propanol serves as an enolate ion.
- 2-Methylbut-2-enal and Pent-2-enal are just the two cross-aldol derivatives.
Therefore, the correct answer will be option (d)
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Answer:
D.
Explanation:
Meets the qualifications!
<span>4FeS2 + 11O2 = 2Fe2O3 + 8SO2</span>
Percent yield is calculated as the actual yield divided by the theoretical yield multiplied by 100.
Actual yield = 55 g ( 1 mol / 159.69 g ) = 0.34 mol Fe2O3
To find for the theoretical yield, we first determine the limiting reactant.
100 g O2 ( 1 mol / 32 g) = 3.13 mol O2
200 g FeS2 (1 mol / 119.98g) = 1.67 mol FeS2
Therefore, the limiting reactant is O2.
Theoretical yield = 3.13 mol O2 ( 2 mol Fe2O3 / 11 mol O2 ) = 0.57 mol Fe2O3
Percent yield = (0.34 mol / 0.57 mol) x 100 = 59.74%