Answer:
after 45 days 9 g left
Explanation:
Given data:
Half life Na-24 = 15 days
Mass of sample = 72 g
Mass remain after 45 days = ?
Solution:
Number of half lives passed:
Number of half lives = time elapsed / half life
Number of half lives = 45 days / 15 days
Number of half lives = 3
At time zero total amount = 72 g
After first half life = 72 g/ 2= 36 g
At 2nd half life = 36 g/2 = 18 g
At 3rd half life = 18 g/2 = 9 g
Thus after 45 days 9 g left.
Answer:
The two ice sheets on Earth today cover most of Greenland and Antarctica. During the last ice age, ice sheets also covered much of North America and Scandinavia. Together, the Antarctic and Greenland ice sheets contain more than 99 percent of the freshwater ice on Earth.
Hope this helps! (:
Answer:
Explanation:
first, you calculate the amount of O2 in moles:
98.0 ÷ 32 = 3.0625
second, the ratio if O2/C3H8 is 5 so you need to calculate O2 in moles with that:
3.0625 ÷ 5 = 0.6125
third, the amount of CO2 in moles also can be calculate by the ratio of C3H8/CO2 which is 3
0.6125 × 3 = 1.8375
then multiply CO2 in moles by its molar mass which is 44 g/mol
1.8375 × 44 = 80.85g
Answer:
they are made up of hard spheres that are in random motion
