Answer:
Explanation:
THE CORECT QUESTION
A 50.0 mL solution of 0.127 M KOH is titrated with 0.254 M HCl. Calculate the pH of the solution after the addition of each of the given amounts of HCl.
SOLUTION
Get the concentration of the HCl first using titration formula
CA X V A / CB VB = NA/ NB
Equation of reation; KOH + HCl => KCl + H2O
CA = 0.254 M
CB = 0.127
VA = 1/0.254 = 3.937
CA (after the addition) = 0.127 x 50 / 3.937
= 1.612 M
But pH = - Log[hydrogen ion]
= -log 1.612
=
Answer:
Explanation: The lowest pressure in a laboratory is 4.0×10^-11Pa
Using Ideal gas equation
PV = nRT
P= 4.0×10^-11Pa
V= 0.020m^3
T= 20+273= 293k
n=number of moles = m/A
Where m is the number of molecules and A is the Avogradro's number=6.02×10²³/mol
R=8.314J/(mol × K)
PV= m/A(RT)
4.0×10^-11 ×0.020 = m/6.02×10²³(8.314×293)
m = 4.0×10^-11×0.020×6.02×10^23 / (8.314×293)
m = 1.98×10^8 molecules
Therefore,the number of molecules is 1.98×10^8
Answer:
D. All of the above
Explanation:
E = MC² is a common equation in physics.
E is energy
M is mass
C is the speed of light
The law was stated by Albert Einstein.
- From this law, it was shown that energy is released when matter is destroyed.
- Mass and energy are equivalent as seen in nuclear reactions where mass is converted to energy.
- Mass and energy is usually conserved in any process and this is a subtle modification of the law of conservation of matter and energy.
- Most of these postulates apply to nuclear reactions which generally do not follow some precepts of chemical laws.
<em>Answer:</em>
<em>An Atom can turn into both solid and liquid form depending on the temperature of its surroundings </em>
<em>Explanation:</em>
<em>Scientists have discovered a new state of physical matter in which atoms can exist as both solid and liquid simultaneously.
Researchers have found, however, that some elements can, when subjected to extreme conditions, take on the properties of both solid and liquid states.</em>
4Al + 3K2SiF6 = 6KF + 3Si + 4AIF3 is the reaction for preparation of silicon by the reduction of K₂SiF6 with Al.
AlF3xH2O-based inorganic compounds are referred to as aluminium fluoride. They are all solids without colour. Aluminium fluoride is a crystalline (sand-like), odourless, white, or colourless powder. In addition to being used to make aluminium, it also functions as a flux in welding processes and in ceramic glazes and enamels.
Silicon (Si) is created by reducing potassium silicofluoride with aluminium as the reducing agent (K2SIF6). While K2SiF6 is reduced to Si in this equation, aluminium is oxidised to aluminium fluoride. As a result, the balanced equation describing aluminum's reduction of K2SiF6 to silicon non-metal is as follows: 4Al + 3K2SiF6 = 6KF + 3Si + 4AIF3
Learn more about aluminium fluoride here:
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