Physics, 19.11.2020 19:00 unknown6669

A student spots an unknown sample on a TLC plate. After developing in hexanes/ethyl acetate 50:50, he/she saw a single spot with an Rf of 0.55. Does this indicate that the unknown material is a pure compound? What can be done to verify the purity of the sample?

Answers: 3

Show answers

Answers

Answer from: bvaughn5915

The given unknown material or compound is a pure compound - yes, it has only one spot.

In the given TLC plate there is only one single spot found thus we can say it is the pure compound as If an impurity is present along with the major compound then there we could observe more spots other than the major compound.

The verification of the purity of the sample can be tested by a general procedure

conduct the TLC of the given compound and a separate TLC consisting of the pure compoundcompare the Rf values of both platesif it matches with the Rf value of the pure compound then the given compound is confirmed. the TLC plate has no spots other than the main compound therefore, it is a pure one.

Thus, The given unknown material or compound is a pure compound - yes, it has only one spot.

Learn more:

link

Answer from: babygirl6571

See explanation

Explanation:

A pure sample is known to give one spot on a chromatogram. This is the first indication that the substance is a pure substance. Since the student saw a single spot, the unknown substance is pure.

Subsequently, the substance can be boiled since it is a liquid. Impure substances boil over a range of temperatures. If the substance is pure, it will have a sharp boiling point which can be compared with boiling points of known substances recorded in literature hence the substance can be correctly identified.

Answer from: Quest

answer: the correct answer is 1.

explanation: there are various process in which a radioactive nuclei decays:

1) alpha decay: in this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. the mass number is reduced by 4 units.

$_a^z\textrm{x}\rightarrow _{a-2}^{z-4}+_2^4\alpha$

2) electron capture: in this decay process, a parent nuclei absorbs an electron and gets converted into a neutron. simply, a proton and an electron combines together to form a neutron. mass number does not change in this process.

$_a^z\textrm{x}+_{-1}^0\textrm{e}\rightarrow _{z-1}^a\textrm{y}$

3) gamma ray emission: it is a decay process in which an unstable nuclei gives excess energy by a spontaneous electromagnetic process. this decay releases $\gamma -radiations$ . this process does not change the mass number.

$_a^z\textrm{x}^*\rightarrow _a^z\textrm{x}+_0^0\gamma$

4) positron emission: it is a type of decay process, in which a proton gets converted to neutron and an electron neutrino. this is also known as $\beta ^+$ -decay. in this the mass number remains same.

$_a^z\textrm{x}\rightarrow _{z-1}^a\textrm{y}+_{+1}^0e$

from the above information, we see that only alpha-decay is producing a change in the mass number of the nucleus.

Answer from: Quest

no simpler subs form complex ones. synthesise = make

Another question on Physics

Physics, 21.06.2019 19:30

Two identical 82 mg dust particles very far apart (pee 0) are moving directly toward each other at a speed of 3698 m/s. the charge on each is-719 ? c. determine how close they will get to each other. let k = 9x109 n-m2/c2 & ignore gravity.

Answers: 1

Answer

Physics, 22.06.2019 02:00

Transfer chemicals from one location to another to weather objects. a-water b-physical weathering c-chemical weathering

Answers: 2

Answer

Physics, 22.06.2019 09:00

Chemical energy is a form of energy. a. heat b. kinetic c. potential d. electromagnetic

Answers: 2

Answer

Physics, 22.06.2019 12:30

Urgent pls a. coal consumption levels off and remains flat. b. petroleum, natural gas, and renewables show an increase in consumption c. more nonrenewable resources continued to be consumed than renewable. d. there is little projected increase in nuclear energy use. e. carbon dioxide emissions are projected to decline as we approach 2040. global energy consumption is defined as the total energy used by an individual or organizations from around the world. use the graph above to analyze the projected energy consumption from now until 2040. which statements in the prompt apply? a) a, b, d b) b, c, d c) a, c, d d) a, b, c, d

Answers: 1

Answer

You know the right answer?

A student spots an unknown sample on a TLC plate. After developing in hexanes/ethyl acetate 50:50, h...

Questions