Tag: chemistry

Questions Related to chemistry

Which of the following have same significant figures?

chemistry measurement and data processing and analysis uncertainties and errors, graphical techniques uncertainty in measurement measurement of properties

  1. $6.02\times 10^{23}$

  2. $7.70\times 10^{-20}$

  3. $7.50$

  4. $0.75$

Show answer
Correct Option: A,B,C
Explanation:

The number of single digits that are important in the coefficient of an expression in scientific notation is termed as significant number.


$(A),(B)$ & $(C)$ have $3$ significant figures.

Wheras, $(D)$ has only $2$ significant figures.

Statement I: The number $5,007$ has three significant figures
Because
Statement II: Zeros between non-zero digits are significant

chemistry measurement and data processing and analysis uncertainties and errors, graphical techniques uncertainty in measurement measurement of properties

  1. one is True, second is  True and currect expilanation

  2. one is true and second is true

  3. one is true  and second is False

  4. one is False and  second is True

  5. False False

Show answer
Correct Option: D
Explanation:

 Statement I: The number $5,007$ has four significant figures
Because
Statement II: Zeros between non-zero digits are significant
Hence, the statement I is false and statement II is true.

Which choice shows the answer to the following mathematical operation with the correct number of significant figures?
$14.5-3.46=$______

chemistry measurement and data processing and analysis uncertainties and errors, graphical techniques uncertainty in measurement measurement of properties

  1. $11$

  2. $10$

  3. $11.04$

  4. $11.0$

  5. $11.4$

Show answer
Correct Option: D
Explanation:

      $14.5-3.46=11.04$

In subtraction, the final answer is written as the same number of decimal places as that of the term with the least number of decimal places.
  $\therefore$ The answer is $11.0$

Which choice shows the answer to the following mathematical operation with the correct number of significant figures?


$2.8\times 8.96 = ? $

chemistry measurement and data processing and analysis uncertainties and errors, graphical techniques uncertainty in measurement measurement of properties

  1. $25.09$

  2. $25.1$

  3. $25$

  4. $25.08$

  5. $25.088$

Show answer
Correct Option: B
Explanation:

In multiplication, the final answer is reported as the same number of decimal places as that of the term with the least number of decimal places.


$2.8\times 8.96=25.088=25.1$

Hence, the correct answer is option $B$.

How many significant digits does the measurement $0.5873g$ possess?

chemistry measurement and data processing and analysis uncertainties and errors, graphical techniques uncertainty in measurement measurement of properties

  1. $1$

  2. $2$

  3. $3$

  4. $4$

  5. $5$

Show answer
Correct Option: D
Explanation:

The significant digits in the number $0.5873g$ are $5,8,7$ and $3$. Therefore, the number of significant digits in the given number are $4$.

Two samples were weighed using different balance and the following data were obtained.
Sample #1=3.719 grams
Sample #2=0.42 gram
The total mass of the samples should be reported as :

chemistry measurement and data processing and analysis uncertainties and errors, graphical techniques uncertainty in measurement measurement of properties

  1. 4 grams

  2. 4.1 grams

  3. 4.139 grams

  4. 4.14 grams

  5. 4.140 grams

Show answer
Correct Option: D
Explanation:

After rounding off to $2$ significant digits, weight of sample $1$ can be reported as $3.72$ grams. Therefore, total mass $= (3.72+0.42)=4.14 $ grams.

What is the final significant digit in the measurement of $16.280g$?

chemistry measurement and data processing and analysis uncertainties and errors, graphical techniques uncertainty in measurement measurement of properties

  1. $1$

  2. $0$

  3. $8$

  4. $6$

  5. $2$

Show answer
Correct Option: B
Explanation:

The significant digits in the number $16.280$ are $1,6,2,8$ and $0$. Therefore, the final significant digit in the given number is $0$.

Which choice shows the answer to the following mathematical operation with the correct number of significant figures?
$\dfrac{12.55}{3.0} =4.18333$

chemistry measurement and data processing and analysis uncertainties and errors, graphical techniques uncertainty in measurement measurement of properties

  1. $4.18333$

  2. $4.2$

  3. $4.18$

  4. $4.183$

  5. 37.45

Show answer
Correct Option: B
Explanation:

In multiplication, the final answer is reported as the same number of decimal places as that of the number with the least decimal places.

Therefore, $4.18333$ should be rounded off to only one decimal place.
Therefore, $\dfrac{12.55}{3.0}=4.2$

Which choice shows the answer to the following mathematical operation with the correct number of significant figures?
$4.51\times{10}^{5}+3.6\times{10}^{3}$

chemistry measurement and data processing and analysis uncertainties and errors, graphical techniques uncertainty in measurement measurement of properties

  1. $4.55\times {10}^{5}$

  2. $8.11\times {10}^{5}$

  3. $4.546\times {10}^{5}$

  4. $8.11\times {10}^{8}$

  5. $4.5\times {10}^{5}$

Show answer
Correct Option: E
Explanation:

In addition, the final product is reported as the same number of decimal places as that of the number with least decimal places.

$\therefore \quad 4.51\times { 10 }^{ 5 }+3.6\times { 10 }^{ 3 }=4.546\times { 10 }^{ 5 }$
                                                  $=4.5\times 10^5$

What is the molecular mass of glucose $C _6H _{12}O _6$ molecule up to 6 significant figures?

chemistry measurement and data processing and analysis uncertainties and errors, graphical techniques uncertainty in measurement measurement of properties

  1. 0180.16

  2. 180.16

  3. 180.1620

  4. 180.162

Show answer
Correct Option: D
Explanation:

Molecular mass of glucose is $180.162$

Therefore, the molecular mass upto six significant figures is $180.162$.