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il63 [147K]
2 years ago
15

A buffer is prepared by dissolving 0.80 moles of NH3 and 0.80 moles of NH4Cl in 1.00 L of aqueous solution. If 0.10 mol of NaOH

is added to 250 mL of this buffer, what is the pH of the resultant solution?
a.10.54
b.4.27
c.8.78
d.9.73
e.5.22
Chemistry
1 answer:
Vikki [24]2 years ago
7 0

Answer:

a. 10.54

Explanation:

reaction is

NH₃ +  NaOH   -----------------NH₄Cl + H₂O

0.10 mol NaOH will consume 0.10 mol NH₃ thereby decreasing the initial amount of moles NH₃ and increasing that of NH₄Cl

mol NH₃  = 0.80 - 010 = .70

mol NH₄Cl = 0.80 + .10 = 0.90

pH = pKₐ + log (( NH₃/NH₄Cl))

pH =  9.26 + log (( 0.90 + 0.70)) = 9.26 + 0.11 = 10.54

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You shine a flashlight into a glass of apple juice. Some of the light bounces off the liquid. Some of it passes through it. Whic
Vilka [71]

Answer:

2. Translucent

4. Reflection

Explanation:

The terms translucent describes the nature of the juice and reflection perfectly fits the property of the light.

A translucent substance is one that partially allows light to pass through it. Since it is said that some of the light bounced back and some passed through, this is translucent.

Also, the light bouncing back is an indicator of reflection. Reflection is a property of light where it bounces back a surface.

7 0
2 years ago
For the quantum number lower case L = 0, how many possible values are there for the quantum number m subscrip l?
hram777 [196]
Quantum number L, angular quantum number, describes the shape of the orbitals. Reliable sources show that the quantum number l = 0 will give an orbital of spherical shape, polar if l = 1, and cloverleaf if l = 2.

The third quantum number is m which is is used to denote the magnetic quantum number. This describes the orientation of a certain orbital in shape. This quantum number can take the values of -l to l. Thus, the only value for m in this case is 0. m = 0.  

Quantum numbers are used to describe the position of the electrons in the orbitals. 
3 0
2 years ago
Please Help Me!!
Cerrena [4.2K]

Answer:

1. Galvanic oxidation. Example is the corrosion of aluminium wires when in contact with copper wires under wet conditions.

2. Rainwater or Damp/moist air

3. Chromium-plated steel screws or stainless steel screws or galvanized steel screws

Explanation:

1. Galvanic oxidation or corrosion occurs when two different metals with different electrode potentials are brought into contact with each other by means of an electrolyte (usually a aqueous solution), such that a redox reaction occurs leading to one metal with the more negative electrode potential (the anode) becoming oxidized, while the other less negative potential (the cathode) is reduced.

In order for galvanic corrosion to occur, three elements are required.

i. Two metals with different corrosion potentials (anode and cathode)

ii. Direct metal-to-metal electrical contact

iii. A conductive electrolyte solution (e.g. water) must connect the two metals on a regular basis.

For example oxidation (corrosion) of aluminium wires when in contact with copper wire under wet conditions.

2. The most likely electrolyte will be rainwater containing dissoved solutes (if the panel is in an exposed part of the house) or damp/moist air.

3. From the table, the most likely screw will be chromium-plated steel screws or stainless steel (made of iron and nickel) screws or galvanized steel (zinc-plated) screws.

All these possible screw components have a more negative electrode potential than copper. Thus they will serve as the anode in a galvanic oxidation with copper.

3 0
2 years ago
In an experiment, hydrochloric acid reacted with different volumes of sodium thiosulfate in water. A yellow precipitate was form
morpeh [17]

Answer:

The time taken for the cross to become invisible decreases.

Explanation:

We know that one of the factors affecting the rate of reaction is the concentration of reactants. From the collision theory, we know that the higher the concentration of reactants, the greater the possibility of effective collision between reactants leading ultimately to an increase in the rate of reaction. Increase in the rate of reaction implies that the reaction takes a shorter time to reach completion.

In the case of the reaction shown in the question, the point when the reaction is completed is observed by the time take for the cross mark to become invisible. If we look at the given data closely, we will notice that the volume of acid was held constant, the volume of thiosulphate was increased gradually while the volume of water was decreased accordingly. This implies that the concentration of the reactants was increased. Decreasing the volume of water increases reactant concentration.

As explained above, increase in reactant concentration increases the rate of reaction. Hence, the rate of reaction of the acid and thiosulphate increases as reactant concentration increases and the cross mark becomes invisible faster. This implies that in the last column for time taken for the cross to become invisible, the values of time decreases steadily as concentration of reactants increases.

5 0
3 years ago
What is the molar mass of a compound?
Masteriza [31]

Answer:

The molar mass of a compound is The mass in grams of 1 mole of the compound (Option A)

Explanation:

Let's take ammonia as an example (NH3)

Mass of N = 14 g

Mass of H = 1 g

Molar mass of ammonia is Mass of N + (Mass of H).3

14 + 3 = 17 g/m

Ammonia is a compound that has 1 mol of N, plus 3 moles of H (see the formula)

The number of atoms in 1 mole of the compound --> This is Avogadro

7 0
2 years ago
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