Which of the following gases is light than air?
CO2
SO2
HCI
NH3
Correct answer is D
No explanation has been provided for this answer.
oxygen and water vapour
oxygen and nitrogen
carbon (IV) acid and noble gases
nitrogen and noble gases
Correct answer is D
No explanation has been provided for this answer.
What is the IUPAC name of the compound represented by the molecular formula NaCIO4?
Sodium tetraoxochlorate (l)
Sodium tetraoxochlorate (IV)
Sodium tetraoxochlorate (VI)
Sodium tetraoxochlorate(VII)
Correct answer is D
No explanation has been provided for this answer.
How many atoms are there in one mole of hydrogen gas? [Avogadro's constant = 6.02 x 1023mol-1]
1.2 x 10 23
6.0 x 10 23
1.2 x10 24
6.0 x 10 24
Correct answer is C
One mole of hydrogen gas has 6.02 x 1023 molecules, and one molecule of hydrogen gas contains 2 atoms of hydrogen
therefore, one mole of hydrogen gas will contain 2 x 6.02 x10^23 atoms
= 1.2 x 10^24 hydrogen atoms
13.5 g mol-1
18.5 g mol-1
47.4 g mol-1
74.0 g mol-1
Correct answer is D
250cm3 of distilled water contains 14.8g of salt(z)
1cm3 of distilled water will contain \(\frac{14.8 x 1}{250}\) of salt (z)
:. 1000cm3 of distilled water will contain \(\frac{14.8 x 1 x 1000}{250}\) = 59.2g/dm33 = \(\frac{concentration in g/dm3}{molar mass}
0.80 = \(\frac{59.2}{molar mass}\)
molar mass = \(\frac{59.2}{0.80}\) = 74.0 g/mol