Answer:
Ca^2+
Explanation:
As we know, more energy is required to remove an electron from a positively charged ion than is required to remove an electron from a neutral atom. Hence, the second ionization energy of calcium is greater than its first ionization energy.
However, the third and fourth ionization energies of calcium are much higher than the second ionization energy because they involve removal of electrons from an inner filed shell. This process requires a lot of energy and is often not feasible.
Hence, the most common ion of calcium must be Ca^2+ where only two electrons are removed from calcium.
A base taste bitter, not sour, so not D, But a base is slippery, so B.
Answer:
oxygen is limiting reactant
Explanation:
Given data:
Mass of phosphorus = 25.0 g
Mass of oxygen = 50.0 g
What is limiting reactant ?
Solution:
Chemical equation:
P₄ + 5O₂ → P₄O₁₀
Number of moles of P₄:
Number of moles = mass/molar mass
Number of moles = 25.0 g/ 123.89 g/mol
Number of moles = 0.20 mol
Number of moles of O₂:
Number of moles = mass/molar mass
Number of moles = 50.0 g/ 32 g/mol
Number of moles = 1.56 mol
now we will compare the moles of reactants with product:
P₄ : P₄O₁₀
1 : 1
0.20 : 0.20
O₂ : P₄O₁₀
5 : 1
1.56 : 1/5×1.56 = 0.312 mol
Less number of moles of product are formed by the oxygen thus it will act as limiting reactant.
A national day is a day on which celebrations mark the nationhood of a nation or state. It may be the date of independence, of becoming a republic, or a significant date for a patron saint or a ruler (such as a birthday, accession, or removal). The national day is often a public holiday.
Answer: To be able to not forget what have they done when they want to re-do it.
to make it easier for the next person to re-do the experiment.
Explanation:
the description of the procedure ensures that when the experiment becomes of a success,specific steps are recorded for improvement of the experiment if maybe the experiment can be done at a short space of time.