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3 years ago

What is the purpose of a buffer?

2 answers:

8 0

buffers resist changes in pH levels, they are used to regulate biological functions that only occur at certain pH levels.

iren [92.7K]3 years ago

4 0

Answer:

To limit pH changes in solution.

Explanation:

Correct answer for *APEX quiz.

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A quantity of CO gas occupies a volume of 0.32 L at 0.90 atm and 323 K . The pressure of the gas is lowered and its temperature

Contact [7]

Mathematical formula of Ideal Gas Law is PV=nRT
where: P-pressure,
V-volume
n-number of moles; m/MW
T-Temperature
m-mass
d-density ; m/V
MW-Molecular Weight
R- Ideal Gas constant. If the units of P,V,n & T are atm, L, mol & K respectively, the value of R is 0.0821 L x atm / K x mol

Substituting the definitions to the original Gas equation becomes:
d= P x MW / (RxT)

Solution : d= .90atm x 28 g/mol (CO) / 0.0821Lxatm / mol x K x 323 K

d = 25.2 g / 26000 mL

d = .0.00096 g/mL is the density of CO under the new conditions

5 0

4 years ago

СН3 – СН = СН2 + НCl → help help help help

Alex

СН₃ – СН = СН₂ + НCl → CH₃-CHCl-CH₃

<h3>Further explanation</h3>

Alkenes are unsaturated hydrocarbons that have a -C = C- double bond.

If there are 2 double bonds it is called an alkadiene, and if there are three double bonds it is called an alkatriene

General formula for Alkenes: CnH2n

addition reactions to alkenes follow Markovnikov's rule. in the addition reaction of hydrogen halide (HX), the halogen atom (X) will be bonded to the carbon atom that binds less H atom.

If the double-bonded carbon atom has the same number of H atoms attached to it, then the X atom will tend to be attached to the carbon atom with the longer alkyl group.

Addition reaction of propene compounds with HCl

СН₃ – СН = СН₂ + НCl → CH₃-CHCl-CH₃

CH - this carbon atom binds fewer H atoms, so Cl is bonded to this bond

5 0

3 years ago

List 3 elements with 6 valence electrons

ra1l [238]

oxygen, sulfur, selenium

3 0

3 years ago

Which electromagnetic wave has the shortest

kozerog [31]

Answer:

The electromagnetic spectrum

Explanation:

ranges from gamma (γ) radiation, which has the shortest wavelength, highest frequency, and greatest energy

3 0

3 years ago

2.70g of Zn (s) reacts with 50.0 mL of 1.00 M HCl solution to produce hydrogen gas according to the reaction. (R = 0.08206 L·atm

Anika [276]

Answer:

a. 0.0413 moles Zn

b. 0.0500 moles HCl

c. HCl is the limiting reactant

d. 0.0250 moles H₂

e. V = 0.56L

Explanation:

The reaction of Zn(s) with HCl is:

Zn(s) + 2HCl (aq) → ZnCl₂ (aq) + H₂(g)

Where 1 mole of Zn reacts with 2 moles of HCl.

a) To convert mass in grams to moles of a substance you need to use molar mass (Molar mass Zn: 65.38g/mol), thus:

2.70g Zn × (1mol / 65.38g) = 0.0413moles of Zn

b. Now, when you have a solution in molarity (Moles / L), you can know the moles of a volume of solution, thus:

Moles HCl:

50.0mL = 0.0500L × (1.00mol / L) = 0.0500 moles HCl

c. The limiting reactant is founded by using the chemical reaction as follows:

For a complete reaction of 0.0500 moles HCl you need:

0.0500 moles HCl × (1 mole Zn / 2 moles HCl) = 0.0250 moles Zn

As you have 0.0413 moles of Zn, and you need just 0.0250 moles for the complete reaction, Zn is the exces reactant and HCl is the limiting reactant

d.As HCl is limiting reactant and 2 moles of HCl react with 1 mole of H₂, moles of hydrogen formed are:

0.0500 moles HCl × (1 mole H₂ / 2 moles HCl) = 0.0250 moles H₂

e. Using PV = nRT, you can find volume of gas, thus:

PV = nRT

V = nRT / P

Where P is pressure 1atm at STP, n are moles, R is gas consant 0.08206Latm/molK and T is absolute temperature 273.15K at STP.

V = 0.0250molesₓ0.082atmL/molKₓ273.15K / 1atm

V = 0.56L

3 0

3 years ago