One of the best buffer choice for pH = 8.0 is Tris with Ka value of 6.3 x 10^-9.
To support this answer, we first calculate for the pKa value as the negative logarithm of the Ka value:
pKa = -log Ka
For Tris, which is an abbreviation for 2-Amino-2-hydroxymethyl-propane-1,3 -diol and has a Ka value of 6.3 x 10^-9, the pKa is
pKa = -log Ka
= -log (6.3x10^-9)
= 8.2
We know that buffers work best when pH is equal to pKa:
pKa = 8.2 = pH
Therefore Tris would be a best buffer at pH = 8.0.
Answer:
Independent: sizes of nails
Dependent: number of paper clips
Controlled: Battery, wire and type of nails
Explanation:
An independent variable is a variable which when changes does not the effect the results of the experiment. It does not depends upon the dependent variable.
A dependent variable is defined as a variable which is affected when the independent variable is changed by the researcher or the experimenter. It depends greatly upon the independent variable.
While a controlled variable is that variable whose value is not changed in an experiment. It contains all the constants.
In the context,
the independent variable are : sizes of nails
the dependent variables are : number of paper clips
the Controlled variables are: Battery, wire and type of nails
The interphase usually lasts the longest
Repeatable
If it’s repeatable and you get the same answer constantly then it’s a good and accurate experiment
Answer:
Mass = 73.73 g
Explanation:
Given data:
Mass of Mg used = 24.48 g
Mass of HCl used = ?
Mass of hydrogen gas produced = 2.04 g
Mass of Magnesium chloride produced = 96.90 g
Solution:
Chemical equation:
Mg + 2HCl → MgCl₂ + H₂
Number of moles of Mg:
Number of moles = mass/ molar mass
Number of moles = 24.48 g/ 24.305 g/mol
Number of moles = 1.01 mol
Now we will compare the moles of Mg with HCl from balance chemical equation.
Mg : HCl
1 ; 2
1.01 : 2/1× 1.01 = 2.02 mol
Mass of HCl react:
Mass = number of moles × molar mass
Mass = 2.02 × 36.5 g/mol
Mass = 73.73 g
