Answer:
(a) oxygen
(b) 154g (to 3sf)
(c) 79.9% (to 3sf)
Explanation:
mass (g) = moles × Mr/Ar
note: eqn means chemical equation
(a)
moles of P = 84.1 ÷ 30.973 = 2.7152 moles
moles of O2 = 85÷2(16) = 2.65625 moles
Assuming all the moles of P is used up,
moles of O2 / moles of phosphorus = 5/4 (according to balanced chemical eqn)
moles of O2 required = 5/4 × 2.7152moles = 3.394 moles (more than supplied which is 2.65625moles)
therefore there is insufficient moles of O2 and the limiting reactant is oxygen.
(b)
moles of P2O5 produced
= 2/5 (according to eqn) × 2.7152
= 1.08608moles
mass of P2O5 produced
= 1.08608 × [ 2(30.973) + 5(16) ]
= 154.164g
= approx. 154g to 3 sig. fig.
(c)
% yield = actual/theoretical yield × 100%
= 123/154 × 100%
= 79.870%
= approx. 79.9% (to 3sf)
Answer:
The correct option is C. The level of organization best represented by the corn plant is : organism, the level of organization directly above organ system organ system
Explanation:
An organism can be described as a living thing made up of organ systems.
Plants are organisms that have levels of organizations similar to animals. Cells in plants make up tissues. There are mainly two types of tissues in plants: the meristematic tissue and non-meristematic tissue.
Just like animals, plants have organ systems. There are two kinds of organ systems mainly in plants: the shoot system and the root system. Hence, option C is the correct option.
Answer:
Nora used a minimal volume of hot solvent, this hot mixture was filtered to remove insoluble impurities. She had to perform a rapid filtration with a minimum of evaporation in a short-stemmed funnel previously heated in an oven, and provided with a pleated filter to increase the filtration rate, so in this way she prevented the product from crystallizing prematurely on the funnel stem.
If with this technique does not reach a pure substance, the process can be repeated by heating the solvent, changing the funnel or looking for a solvent with high dissolution power of the substance.
Explanation:
The solid products obtained in a reaction are usually accompanied by impurities that must be removed in order to dispose of the desired product in the highest possible purity. The most suitable method for removing impurities that contaminate a solid is by crystallization either in a pure solvent or in a mixture of solvents. This procedure is given the generic name of recrystallization.
Lithium i think!!
hope this helps
