Tag: chemistry

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Questions Related to chemistry

Multiple choice chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

Hydrolysis of urea is an example of

  1. Homogenious reaction

  2. heterogenious reaction

  3. Biomolecular reaction

  4. Both a and b
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Enzymes are biological catalysts which catalyze the biochemical reactions in living organisms.

Hydrolysis of urea by urease is an example of  biochemical catalysis.

 

Multiple choice chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

Predict block, group and period of $Sb$.

  1. Block-$p$, Period-$5$, Group-$15$
  2. Block-$p$, Period-$5$, Group-$14$
  3. Block-$s$, Period-$5$, Group-$13$
  4. Block-$s$, Period-$5$, Group-$11$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Antimony is a chemical element with symbol $Sb$ (from Latin: stibium) and atomic number $51$,group $15$ (pnictogens), $p$-block,period $5$.

Multiple choice chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

Based on modern classification of periodic table atomic number increases on moving from _________ in periodic table.

  1. left to right

  2. right to left

  3. straight

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

Elements in the same period tend to have shared chemistry and exhibit a  trend in properties with increasing atomic number from left to right.

Multiple choice chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

The modern periodic table is most_________ form of periodic table.

  1. insignificant

  2. Significant

  3. Both A and B

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

In the standard periodic table, the elements are listed in order of increasing atomic number. Thus, it is relatively easy to predict the chemical properties of an element if one knows the properties of the elements around it i.e. it is more significant form of periodic table.

Multiple choice chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

Significance of classification of periodic table is to ___________.

  1. predict the blocks of elements

  2. predicts the groups of elements

  3. both A and B

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Periodic classification of elements is the method by which elements are grouped on the basis of their characteristics. Classification of elements in groups provide us a fixed pattern in which the elements change their properties periodically. Periodic table made the study of physical and chemical properties of elements simple and organized.

Multiple choice chemistry classification of elements- the periodic table introduction to periodic table necessity of classification need for classification

Classification of periodic table based on atomic number is given by:

  1. Mendeleev's

  2. Mosley

  3. Both A and B

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

Henry Moseley found a relationship between the X-ray wavelength of an element and its atomic number. Moseley's discovery showed that atomic numbers were in fact based upon experimental measurements.

Multiple choice chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

Alkali and alkaline earth metals are ________ elements.

  1. same

  2. different

  3. both A and B

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Alkali and alkaline earth metals are group I and group II elements of s block representative elements with ns$^1$ and ns$^2$ valence shell configuration respectively.


Hence, option B is correct.

Multiple choice chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

Lanthanoids are also called as ___________.

  1. Transition elements

  2. Rare earth elements

  3. Both A and B

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

Rare earth metals are a group of chemically similar metallic elements comprising the lanthanide series and (usually) scandium and yttrium. They are not especially rare, but they tend to occur together in nature and are difficult to separate from one another.

Multiple choice chemistry hydroxy compounds and ethers physical properties of phenol physical properties of alcohols and phenols organic compounds with functional group containing oxygen (part-1)

Alcohols of low molecular weight are:

  1. soluble in water

  2. soluble in water on heating

  3. insoluble in water

  4. insoluble in all solvents.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Alcohols of low molecular weight are soluble in water while that of high molecular weight are insoluble in water .because of high hydrogen bonding in low molecular weight Alcinous.

Multiple choice chemistry hydroxy compounds and ethers physical properties of phenol physical properties of alcohols and phenols organic compounds with functional group containing oxygen (part-1)

Which of the following statements is not correctly showing the trend of the properties mentioned ?

  1. $CH _3CH _2OH > CH _3CH _2CH _2OH > \underset {(Solubility)}{CH _3CH _2CH _2CH _2OH}$
  2. $CH _3CH _2OH > CH _3CH _2CH _2OH > \underset {(Boiling point)}{CH _3CH _2CH _2CH _2OH}$
  3. $CH _3CH _2CH _2OH > CH _3{\underset{CH _3}{\underset{|}{CH}}}-CH _2OH >\underset{Boiling \, point}{CH _3-\underset{CH _3}{\underset{|}{\overset{CH _3}{\overset{|}C}}}-OH}$
  4. $CH _3-{\underset{CH _3}{\underset{|}{\overset{CH _3}{\overset{|}{C}}}}}-OH$<$CH _3{\underset{CH _3}{\underset{|}{CH}}}-CH _2OH$ <$CH _3CH _2CH _CH _2OH$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Boiling point and solubility of alcohols is determined by the ease and extent of H-bonding among the alcohol molecules. More is the hydrogen bonding higher is the boiling point and solubility in water. Thus, tertiary alcohols being highly hindered will have least hydrogen bonding and thus low boiling point/solubility as compared to less hindered secondary alcohol.
Therefore the order of boiling point is primary alcohol>secondary alcohol>tertiary alcohol as:
$CH _3CH _2CH _2OH>CH _3CH(CH _3)CH _2OH>CH _3C(CH _3) _2OH$
In case of linear versus branched alcohol, linear alcohol has higher melting/boiling points due to better stacking and surface area contact.
But in case of highly branched vs. branched molecules more sphere-like structure of the molecule better is the stacking thus higher will be the melting point. Thus order of melting point will be
$CH _3CH(CH _3)CH _2OH<CH _3C(CH _3) _2OH<CH _3CH _2CH _2CH _2OH$
A and B. Solubility and boiling point of alcohols depends on the chain length. Longer is the chain length, lesser is the solubility/boiling point as the extent of H-bonding decreases. Also, the hydrophobic nature of the hydrocarbon chain reduces the solubility.
thus order of solubility and boiling point will be:
$CH _3CH _2OH>CH _3CH _2CH _2OH>CH _3CH _2CH _2CH _2OH$