6
6.8
6.9
7
7.1
Correct answer is C
the relative atomic mass of lithium = percentage abundance times the mass number of the first isotope + percentage abundance times the mass number of the second isotope.
the relative atomic mass of lithium = ( \(\frac{90}{100} \times7 + \frac{10}{100} \times 6\)) =(( 0.9 x 7) + (0.1 x 6)) = 6.3 + 0.6 = 6.9.
Why does the treatment of cotton fabrics with dilute acids weaken the materials?
Cotton is hydrolysed completely to glucose
The fabrics are soluble in dilute acids
The molecular chains are partially broken
The molecular chain length f the fabric increases
The thread holding the fabric together Is completely destroyed.
Correct answer is C
No explanation has been provided for this answer.
CH3Br
C2H5Br
C3H5Br
C3H7Br
C4H9Br
Correct answer is D
No explanation has been provided for this answer.
3.2 g
3.25 g
6.4 g
6.5 g
64.0 g
Correct answer is C
No explanation has been provided for this answer.
Which element is the most electronegative?
calcium
fluorine
iodine
oxygen
sodium
Correct answer is B
No explanation has been provided for this answer.