Mass of the compound = 0.24g
Mass of boron = 0.096 g
Mass of oxygen = 0.144 g
Percentage of boron = \(\frac{\text{Mass of boron}}{\text{ Mass of compound}}\) x 100 = \(\frac{ 0.096g}{0.240 g}\) x 100 = 40%
Percentage of oxygen =\(\frac{\text{Mass of oxygen}}{\text{ Mass of compound }}\)x 100 = \(\frac{0.144g}{0.240g }\)x 100 = 60%
Alternative method
Percentage of oxygen =100 - percentage of boron
=100 - 40
= 60%
Use these adverbs to fill in the blanks in the sentences below.
awfully sorrowfully completely loftily carefully differently quickly nonchalantly
(i) The report must be read ________ so that performance can be improved.
(ii) At the interview, Sameer answered our questions _________, shrugging his shoulders.
(iii) We all behave _________ when we are tired or hungry.
(iv) The teacher shook her head ________ when Ravi lied to her.
(v) I ________ forgot about it.
(vi) When I complimented Revathi on her success, she just smiled ________ and turned away.
(vii) The President of the Company is ________ busy and will not be able to meet you.
(viii) I finished my work ________ so that I could go out to play