Tag: chemistry

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Multiple choice chemistry periodic table development of the modern periodic table into the history mendeleef's periodic table

The periodic table of today owes its development to two chemists namely:

  1. Rutherford and Moseley

  2. Alexander Newlands and Dobereiner

  3. Dmitri Mendeleev and Lothar Meyer

  4. de Broglie and Neil Bohr
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The periodic table of today owes its development to two chemists namely the Russian chemist Dmitri Mendeleev and the German chemist J. Lother Meyer. In 1869, they independently proposed that when the elements are arranged in the increasing order of their atomic weights, similarities in physical and chemical properties appear at regular intervals.

Multiple choice chemistry periodic table development of the modern periodic table into the history mendeleef's periodic table

Which prediction(s) is/are incorrect according to the Lother Meyer's curve?

  1. Each peak of the curve is occupied by the alkali metals

  2. Alkaline earth metals occupy ascending positions of curve

  3. Atomic volume increases first and then decreases in a period (which is defined later) in Lother Meyer's curve

  4. Identically placed elements in the atomic volume vs atomic mass curve occur in the same period in the periodic table
Reveal answer Fill a bubble to check yourself
B,C,D Correct answer
Explanation

Lothar Meyer - Meyers Curve:

1.Plotted the atomic volumes of the elements against the atomic weight, and found that the chemical properties of the element recur periodically.

2.Also notice that the elements occupying the corresponding position of the curve show similar chemical properties.

If we see the atomic mass versus atomic volume curve, we will notice the following features:

i)Alkali metals such as $Na, K, Rb$ which have similar properties occur as peaks of the curve.

ii) Halogen elements like $F, Cl, Br$ which have similar properties occur at the rising or the ascending part of the curve.

iii) Noble gasses such as $Ne, Ar, Kr$ which have similar properties occur just before the alkali elements.

So option A is correct, B,C & D are incorrect.

Hence options B,C & D are correct.

Multiple choice chemistry rocks and minerals petroleum properties of alkanes petroleum and natural gas

LPG is ___________ .

  1. Liquefied petroleum gas

  2. Low petroleum gas

  3. Liquid pressure gas

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Liquefied petroleum gas or it is also called liquid petroleum gas abbreviated as LPG. 

Also referred to as propane or butane, are flammable mixtures of hydrocarbon gases used as fuel in heating appliances and cooking equipment.

Hence, option A is correct.

Multiple choice chemistry rocks and minerals petroleum properties of alkanes petroleum and natural gas

Ethyl bromide reacts with sodium lead alloy to form?

  1. Tetraethyl lead

  2. Ethyl sodium

  3. Ethane

  4. Wthene
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When we treat ethyl bromide with lead sodium alloy we get tetra ethyl lead [TEL]


$4NaPb+4CH _3CH _2Br\longrightarrow \overset {\uparrow Tetraethyllead}{(CH _3CH _2) _4Pb}+4NaCl+3Pb$

TEL is used to increase their efficiency and performance.

Multiple choice chemistry rocks and minerals petroleum properties of alkanes petroleum and natural gas

Identify the chemical which is used to detect leakage of LPG ;

  1. Methyl mercaptan

  2. Propyl mercaptan

  3. Ethyl mercaptan

  4. n-butyl mercaptan
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ethyl mercaptan is added to gas, which possesses that strong odour of rotten cabbages. The smell helps us detect where there is a leak, which actually makes a lot of sense from safety and security perspective.