Answer : The reaction will produce (B) 1.57 mole of magnesium hydroxide and (D) 3.14 mole of sodium chlorate.
Explanation :
First we have to calculate the limiting and excess reagent.
The balanced chemical reaction is,
From the balanced reaction we conclude that
As, 1 moles of react with 2 mole of
So, 2.72 moles of react with
moles of
That means, in the given balanced reaction, is a limiting reagent because it limits the formation of products and
is an excess reagent.
Now we have to calculate the moles of and
by using the moles of limiting reagent.
As, 2 moles of react to give 1 mole of
So, 3.14 moles of react to give
moles of
And,
As, 2 moles of react to give 2 mole of
So, 3.14 moles of react to give 3.14 moles of
Therefore, the reaction will produce (B) 1.57 mole of magnesium hydroxide and (D) 3.14 mole of sodium chlorate.
Answer:
NH₃/NH₄Cl
Explanation:
We can calculate the pH of a buffer using the Henderson-Hasselbalch's equation.
If the concentration of the acid is equal to that of the base, the pH will be equal to the pKa of the buffer. The optimum range of work of pH is pKa ± 1.
Let's consider the following buffers and their pKa.
The optimum buffer is NH₃/NH₄Cl.
Answer:
A scandium-48 nucleus undergoes beta-minus decay to produce a titanium-48 nucleus.
.
Explanation:
There are two types of beta decay modes: beta-minus and beta-plus.
In both decay modes, the mass number of the nucleus stays the same.
However, in a beta-minus decay, the atomic number of the nucleus increases by one. In a beta-plus decay, the atomic number decreases by one.
Each beta-minus decay releases one electron and one electron antineutrino. Each beta-plus decay releases one positron and one electron neutrino.
Look up the atomic number and relative atomic mass for the element scandium.
This question did not specify whether the decay here is beta-plus or a beta-minus. However, the relative atomic mass of this element can give a rough estimate of the mode of decay.
Each element (e.g, ) can have multiple isotopes. These isotopes differ in mass. The relative atomic mass of an element is an average across all isotopes of this element. This mass is weighted based on the relative abundance of the isotopes. Its value should be closest to the most stable (and hence the most abundant) isotope.
The mass number of scandium-48 is significantly larger than the relative atomic mass of this element. In other words, this isotope contains more neutrons than isotopes that are more stable. There's a tendency for that neutron to convert to a proton- by beta-minus decay, for example.
The atomic number of the nucleus will increase by 1. . That corresponds to titanium. The mass number stays the same at
. Hence the daughter nucleus would be titanium-48. Note that two other particles: one electron and one electron
and one antineutrino
(note the bar.) The neutrino helps balance the lepton number of this reaction.