What is commonly used to run a central heating system?

1 answer:

7 0

Answer :- Electrical energy

Explanation :-
Geothermal energy is too large scale
solar energy is inefficient
Nuclear does more harm

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What equation in the blast furnace extraction of iron is not a redox reaction?

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The decomposition of limestone CaCO3 > CaO + CO2

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3 years ago

The molar absorptivity of a tyrosine residue at 280 nm is 2000 M-1cm-1, while for tryptophan it is 5500 M-1cm-1. A protein has b

adelina 88 [10]

Answer:

There are 4 tryptophans in the protein.

Explanation:

According to question, protein contains one tyrosine residue and say x number of tryptophans.

Concentration of protein solution = 1.0 micromolar = $1.0\times 10^{-6} Molar$

Molar absorptivity of a protein solution : $\epsilon$

$\epsilon = \epsilon _{tyro}+\epsilon _{tryp}$

$=1\times 2000 M^{-1}cm^{-1}+x\times 5500 M^{-1}cm^{-1}$

Length of the cuvette = l = 1.0 cm

Absorbance of protein solution at 280 nm = A = 0.024

$A=\epsilon \times l\times c$ ( Beer-Lambert's law)

$0.024=(1\times 2000 M^{-1}cm^{-1}+x\times 5500 M^{-1}cm^{-1})\times 1 cm\times 1.0\times 10^{-6} M$

Solving for x :

x = 4

There are 4 tryptophans in the protein.

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3 years ago

A chemist prepares a solution of barium acetate by measuring out of barium acetate into a volumetric flask and filling the flask

leonid [27]

The given question is incomplete. The complete question is :

A chemist prepares a solution of barium acetate by measuring out 32 g of barium acetate into a 350 ml volumetric flask and filling the flask to the mark with water. Calculate the concentration in of the chemist's barium acetate solution. Round your answer to significant digits.

Answer: The concentration of barium acetate solution is 0.375 mol/L

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

$Molarity=\frac{n\times 1000}{V_s}$