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murzikaleks [220]
1 year ago
12

1. john needs to create a buffered solution at a ph of 3.5 for his biomedical laboratory

Chemistry
1 answer:
Lunna [17]1 year ago
6 0

Answer:

Use a ratio of 0.44 mol lactate to 1 mol of lactic acid  

Explanation:

John could prepare a lactate buffer.

He can use the Henderson-Hasselbalch equation to find the acid/base ratio for the buffer.

\text{pH} = \text{pK}_{\text{a}} + \log\dfrac{\text{[A$^{-}$]}}{\text{[HA]}}\\\\3.5 = 3.86 + \log\dfrac{\text{[A$^{-}$]}}{\text{[HA]}}\\\\\log\dfrac{\text{[A$^{-}$]}}{\text{[HA]}} = 3.5 - 3.86 = -0.36\\\\\dfrac{\text{[A$^{-}$]}}{\text{[HA]}} = 10^{-0.36} = \mathbf{0.44}

He should use a ratio of 0.44 mol lactate to 1 mol of lactic acid.

For example, he could mix equal volumes of 0.044 mol·L⁻¹ lactate and 0.1 mol·L⁻¹ lactic acid.

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Which of the following classification of matter includes material that can no longer be identified by their individual propertie
xz_007 [3.2K]
A compound consists of 2 or more elements that are combined chemically in such a way that the elements themselves can no longer be identified by their individual properties. So the Answer is A.
4 0
2 years ago
Read 2 more answers
2. Suggest four ways in which the concentration of PH3 could be increased in an equilibrium described by the following equation:
Nesterboy [21]

Answer

  • increase in temperature
  • decrease in pressure
  • continuous removal of PH3
  • adding more of P into the system

Explanation:

        In the reaction   P4(g)+6H2(g) ⇌ 4PH3(g);

  • The effect of temperature on equilibrium has to do with the heat of reaction. Recall that for an endothermic reaction, heat is absorbed in the reaction, and the value of ΔH is positive. Thus, for an endothermic reaction, we can picture heat as being a reactant:

        heat+A⇌BΔH=+

  • Since the reaction is endothermic reaction, heat is a absorbed. Decreasing the temperature will shift the equilibrium to the left, while increasing the temperature will shift the equilibrium to the right forming more of PH3.
  • According to Le Chatelier’s principle, adding additional reactant to a system will shift the equilibrium to the right, towards the side of the products. In the same Way, reducing the concentration of the product will also shift equilibrium to the right continually forming PH3 as it is removed.

4 0
1 year ago
The interior of a refrigerator has a volume of 0.600 m3. the temperature inside the refrigerator in 282 k, and the pressure is 1
Dafna11 [192]
In this instance we can use the ideal gas law equation to find the number of moles of gas inside the refrigerator 
PV = nRT
where 
P - pressure - 101 000 Pa
V - volume - 0.600 m³
n - number of moles
R - universal gas constant - 8.314 J/mol.K
T - temperature - 282 K
substituting these values in the equation 
101 000 Pa x 0.600 m³ = n x  8.314 J/mol.K x 282 K
n = 25.8 mol
there are 25.8 mol of the gas
to find the mass of gas
mass of gas = number of moles x molar mass of gas
mass = 25.8 mol x 29 g/mol  = 748.2 g
mass of gas present is 748.2 g 
6 0
1 year ago
In each row, check the box under the compound that can reasonably be expected to be more acidic in aqueous solution, e.g. have t
vredina [299]

Answer:

HCH_{3}SO_{2}

H_{3}PO_{3}

HClO_{2}

Explanation:

Every acid (HA) tends to disolve into proton (H^{+}) and anion (A^{-}) in aqueous solution. Acid strength can be determined by measuring this tendency to separate into proton an anion. Strength of an acid can be quantified by its acid dissociation value - Ka. A strong acid will have a tendency to easily release proton and will have larger Ka value and smaller logarithmic value (pKa = - logKa) similar to calculating pH of the solution. So the easiest way to resolve this issue is by looking for Ka or pKa value of the acid (This table may be useful in more complex tasks and is attached below). However, stronger acid can be determined elsehow.

a) Carbon is element 14 with 4 valent electrons and sulfur is element 16 with 6 valence electrons. Thus, sulfur has stronger electronegativity (tendency to attract bonded electrons towards itself). This means that sulfur will hold oxygen tighter to itself so the hydrogen bond to it can be more easily separated from it. HCH_{3}SO_{2} is more acidic in aqueous solution.

b) In H_{3}PO_{4}, phosphorus holds one double bond with oxygen and three OH group equally. To show an acidic tendency, phosphorus would need to let go one hydrogen out of one of OH groups. In H_{3}PO_{3}, phosporus holds two double bong with oxygen, one OH and one hydrogen, all single and lonely, ready to leave phosphorus and show acidic characteristics in aqueous solution. Thus, H_{3}PO_{3} is more acidic compound.

C) In all Cl acids, the electron density is placed around Cl so the more oxygen around Cl, the more acidic will be the chemical. This is comparable to an oxidation state - the bigger oxidation state, the stronger acid will be:

HClO_{4}  ^{+7} >HClO_{3}^{+5} >HClO_{2}^{+3} >HClO_{}^{+1}

HClO_{2} can reasonably be expected to be more acidic in aqueous solution.

4 0
2 years ago
in a typical person, the level of glucose is about 85 mg/ 100 mL of blood. if an average body contains about 11 pt of blood, how
Vanyuwa [196]

Let's note that 1 pint = 473.1765 mL, so 11 pints should be 5204.9415 mL.

We make a proportion out of the word problem

(85 mg glucose/ 100 mL) times (1 g/ 1000 mg) = 4.4242 grams of glucose

5 0
1 year ago
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