Answer:
- Starch is a polysaccharide comprising glucose monomers joined in α 1,4 linkages. or
- Starch is a long-chain polymer of glucose molecules joined together. or
- A starch is a complex polysaccharide made up of a large number of glucose units joined together by glycosidic bonds.
Explanation:
starch, a white, granular, organic chemical that is produced by all green plants. Starch is a soft, white, tasteless powder that is insoluble in cold water, alcohol, or other solvents.
Starch is amongst the most abundant plant products and is a mixture of two polymers, amylose and amylopectin. During food processing starch is transformed by hydrothermal treatments. ... The structure of starch is also influenced by specific and non-specific interactions with other food constituents and ingredients.
Chemical reaction:
2H2S (g) ⇄ 2H2(g) + S2(g)
The equilibrium constant is given by: Kc = [H2]^2 * [S2] / [H2S]^2 = 1.67 * 10^ -7
The initial concentration is 0.0125 mol / 0.500 L = 0.0250 M
Make a table showing the initial concentrations, the change and the final concentrations of each species
2H2S (g) ⇄ 2H2(g) + S2(g)
start 0.0250M 0 0
change - 2x +2x + x
end 0.0250 - 2x 2x x
Kc = (2x)^2 (x) / (0.0250 - 2x)^2
Kc = 4x^3 / (0.0250 - 2x)^2
To solve that equation in an easy way you can assume that 2x is << 0.0250, which leads to
Kc = 4x^3 / (0.0250)^2 = 1.67 * 10^ -7
=> x^3 = 1.67 * 10^ -7 * 0.0250 / 4 = 2.6 * 10 ^-11
=> x = 2.97 * 10^ -4 M
With this you can check that your assumption that x << 0.0250 is good and continue.
From the table you know that the concentrations at equilibrium are:
[H2] = 2x = 2 * 2.97 * 10 ^ -4 M = 5.94 * 10 ^ -4
[S2] = x = 2.97 * 10^ -4 M
Answer:
18.8 mL
Explanation:
The dilution formula states that the product between the initial molarity and the initial volume should be equal to the product between the final molarity and the final volume, since the number of moles of a substance remains constant in a dilution process:
![c_1V_1 = c_2V_2](https://tex.z-dn.net/?f=c_1V_1%20%3D%20c_2V_2)
We are given the initial molarity of the stock solution
, the final molarity of the diluted solution
and the final volume of the diluted solution
.
Rearranging the expression for the volume of the stock solution, we get:
![V_1 = \frac{c_2V_2}{c_1} = \frac{0.500~M\cdot 225 mL}{6.00 M} = 18.8~mL](https://tex.z-dn.net/?f=V_1%20%3D%20%5Cfrac%7Bc_2V_2%7D%7Bc_1%7D%20%3D%20%5Cfrac%7B0.500~M%5Ccdot%20225%20mL%7D%7B6.00%20M%7D%20%3D%2018.8~mL)
Therefore, 18.8 mL of the stock solution are required.
NaOH + HCl => NaCl + H2O
1 mol of NaOH react with 1 mol of HCL
The molecular mass of NaOH is 39.997
The molecular mass of HCl is 36.46
Moles of HCl
=18.73/36.46
=0.5137
Mole of NaOH
=23.26/39.997
=0.5815
moles of NaOH >moles of HCl
so there are not enough HCl
the answer is HCl
Answer:
R = 12 ohms
Explanation:
It is given that,
Supply voltage is 12 V
Current in the circuit is 1 A
We need to find the resistance of the circuit. Ohm's law gives the relationship between current, voltage and resistance as follows :
V = IR
![R=\dfrac{V}{I}\\\\R=\dfrac{12}{1}\\\\R=12\ \Omega](https://tex.z-dn.net/?f=R%3D%5Cdfrac%7BV%7D%7BI%7D%5C%5C%5C%5CR%3D%5Cdfrac%7B12%7D%7B1%7D%5C%5C%5C%5CR%3D12%5C%20%5COmega)
So, the resistance of the circuit R is 12 ohms.