All categories

4 years ago

What is the function of an indicator in a titration

Chemistry

1 answer:

Tpy6a [65]4 years ago

8 0

Answer:

The function of an indicator in a titration is to indicate the equivalence point.

Explanation:

Titration is a procedure that uses the properties of the acid - base reactions to determine the mole concentration of an unknown solution from the known mole concentraion of other solution. One of the solution is the base and the other is the acid.

At the equivalence point, where the number of H⁺ ions is equal to the number of OH⁻ ions, there is a drastic change of the acidity (or alkalinity) of the solution.

Then, the chemical indicators are substances that change color at the equivalence point, telling the chemist that the equivalence point has been reached and the titration has finished.

You might be interested in

How was Ohm's Law proven wrong in 1909?

maksim [4K]

Answer:

Ohm's law states that Voltage is directly proportional to the Current passing through the conductor. It increases in case of conductors and decreases in case of semi-conductors. Hence Resistivity turned out to be a variable making the Resistance a variable too and hence proving Ohm's Law wrong.

Explanation:

7 0

4 years ago

Why is sterilising the water rarely used in treating the sewage water?

Marina86 [1]

Answer:

Sterilizing the water rarely used in treating the sewage water is described below in details.

Explanation:

Sterilization is the application of a chemical or physical system to eradicate all microorganisms, concluding comprehensive amounts of bacterial content. Heat treatment is the most relevant approach for the sterilization of waste-water that accommodates large levels of masses. well now sterilizing the water is un-usually practiced in managing the sewage water.

7 0

3 years ago

Chemical Reactions/Neutralization Reactions

aliina [53]

Answer:

Hydrochloric acid + sodium hydroxide -> sodium chloride + water

Sulphuric acid + copper hydroxide -> copper sulphate + water

Nitric acid + sodium hydroxide -> sodium nitrate + water

Hydrochloric acid + calcium hydroxide -> calcium chloride + water

Sulphuric acid + potassium hydroxide -> potassium sulphate + water

Hydrochloric acid + lithium hydroxide -> lithium chloride + water

Nitric acid + magnesium hydroxide -> magnesium nitrate + water

7 0

3 years ago

At a certain temperature, 0.740 mol of so3 is placed in a 4.00 l container. so_{3}(g)\rightleftharpoons 2so_{2}(g)+o_{2}(g) at e

Phoenix [80]

Answer : The equilibrium constant kc is 4.76 x 10⁻³

Explanation :

The given equilibrium reaction is

$2SO_{3} (g) \leftrightarrow 2SO_{2} (g) + O_{2} (g)$

Step 1 : Set up ICE table

Let us set up an ICE table for this reaction .

The initial concentration of SO₃ is

$Concentration = \frac{mol}{L} = \frac{0.740mol}{4L} = 0.185 M$

The initial concentrations of products are 0.

Let us assume x is the change .

Please refer the attached picture.

Step 2 : Use the given value to find x

From the ICE table, we can see that at equilibrium, concentration of O₂ is x

But we have been given that , at equilibrium we have 0.190 mol of O₂ .

Let us convert this to concentration unit.

Concentration of O₂ at equilibrium = $\frac{mol}{L} = \frac{0.190mol}{4L} = 0.0475 M$

But concentration of O₂ from the ICE table is x.

Therefore we have x = 0.0475 M

Step 3 : Using x , find equilibrium concentrations

Using this value, let us write the equilibrium concentrations of the given species.

[SO₃]eq = 0.185 M - 2x = 0.185 - 2(0.0475) = 0.09 M

[SO₂]eq = 2x = 0.095 M

[O₂]eq = x = 0.0475 M

Step 4 : Set up equation for kc and solve it

The equilibrium constant kc is calculated as,

$k_{c} = \frac{[SO_{2}]^{2} [O_{2}]}{[SO_{3}]^{2}}$

Let us plug in the above equilibrium values.

$k_{c} = \frac{(0.095)^{2} (0.0475)}{(0.09)^{2}}$

$k_{c} = \frac{0.00042869}{0.09}$

$k_{c} = 4.76 \times 10^{-3}$

The equilibrium constant kc is 4.76 x 10⁻³

3 0

3 years ago

what is the indication that tells us what charge a transitional metal has since they dont have a set trend

Arlecino [84]

Answer:

Roman numbering in IUPAC naming system

Explanation:

This is quite an open question. Let's firstly separate the periodic table into two standard groups: group A elements and group B elements (transition metals).

The charge (or the oxidation state) of an element in group A can be identified by the group number. For example, group 1A elements would always have a charge of +1, as they have only one valence electron to lose.

Similar trend applies to group 2A: each element in that group would have a charge of +2, as each atom has 2 valence electrons to lose to become a cation.

You will notice that this is true fro group 3A and group 4A as well. Now, since an octet is the desired state for any species, starting with group 5A, it's easier to gain 3 electrons for species than lose 5 electrons to obtain an octer, meaning we'd expect -3 oxidation state for group 5A elements, -2 oxidation state for group 6A elements and -1 oxidation state for group 7A elements.

Notice that in the majority of cases, this is the standard trend and we'd generally only have one predominant oxidation state.

Considering group B, the transition metals, most of them have several oxidation states. That's why we usually memorize the ones which only have one oxidation state (such as zinc, silver) and in any other case when a transition metal has several oxidation states, they're identified in the name by using Roman numbering system.

Let's look at an example. Assume the problem states we have a salt which is iron chloride. This would be an improper name, as iron has two oxidation states: +2 and +3. That's why we have the rules of IUPAC naming to avoid ambiguity. If we had iron with an oxidation state of +2, we'd call the salt iron(II) chloride. An oxidation state of +3 would indicate iron(III) chloride.

To summarize, the main key of knowing the charge of a transition metal in a compound is to follow the IUPAC naming rules.

7 0

3 years ago