value of HEPES is 7.5.
A proper amount of HEPES is mixed with distilled water (sterilized) to avoid any contamination. After that, check the pH with the help of pH scale or pH meter.
First, take the basic form of HEPES and then add hydrochloric acid drop by drop to bring down the pH at 8.5.
When pH reaches 8.5; the buffer solution is filtered and placed in the glass container and then covered by aluminium foil.
Answer:
41.44 g
Explanation:
First of all, we must put down the equation of the reaction;
Number of moles of CaO = 33g/56 g/mol = 0.59 moles
Number of moles of H20 = 10g/18 g/mol = 0.56 moles
Since the reaction is in 1:1 mole ration, H2O is the limiting reactant
Hence;
mass of Ca(OH)2 produced = 0.56 moles * 74 g/mol = 41.44 g
Answer:
80.92, Krypton
Explanation:
<u>What is effusion?</u>
• It is a process where gas escapes through a pinhole (a very small hole) into a region of low pressure or vacuum
<u>Graham's law of effusion of </u><u>gas</u>
• states that at a given constant temperature and pressure, the rate of effusion of gases is inversely proportional to the square root of their molar masses
<u>Calculations</u>
Nitrogen exist as N₂ at room temperature, thus its molar mass is 2(14)= 28.
Let the rate and molar mass of unknown gas be Rate₂ and M₂ respectively.
Since N₂ effuses 1.7 times as fast as the unknown gas,
Rate₁= 1.7(Rate₂)
Square both sides:
Multiply both sides by 28:
2.89(28)= M₂
M₂= 80.92
<u>Identity of </u><u>gas</u>
The molar mass of 80.92 lies between Bromine and Krypton. However since Bromine exist as Br₂, the value of it's molar mass would be 159.8 instead. Hence, Bromine is eliminated.
If the gas is a diatomic element, the atomic weight is 80.92 ÷2= 40.46. Thus, we are now considering if Argon could be its identity. However, Argon is a noble gas and will not exist as a diatomic element. Argon is therefore eliminated too.
Thus based on the above reasoning, its probable identity is Krypton.
