Question

8. A molecule of water is made up of 2 atoms of hydrogen and 1 atom of oxygen. What per cent of the atoms of
a water molecule is oxygen?
9. Sterling silver is an alloy combining 925 parts of pure silver and 75 parts of another metal, such as copper.
What per cent of sterling silver is not pure
silver?
10. Prashant spends 4 hours a day on his self-study, 1 hour playing video games and 1 hour in doing workouts
at fitness centre. What per cent of the day does Prashant spend on these activities?​

Answer 1

Answer:

8. molecular mass of water=18gram

atomic mass of oxygen=16gram

per cent of the atoms of

a water molecule is oxygen=16/18×100

1600/18=88.89%

Answer 2

Answer:

25%

10 . 4 hour his self study