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.
evaporation. When a substance undergoes a change of matter from a solid to gas, it is the process of evaporation.
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Answer:
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if 1 teacher cant teach all subjects how come 1 student can learn all subjects ?
Answer:
Explanation:
Iron is Fe, nitrogen is N. Nitrogen is diatomic, which means it occurs as a molecular pair by itself. Iron III nitride has a chemical formula of FeN because nitrogen has a charge of 3-, and iron III tells us the iron has a charge of 3+ so you just need one of each to make the charges balance and the compound neutral.
Answer:
V₂ =279.9 cm³
Explanation:
Given data:
Initial volume = 360 cm³
Initial temperature = 50°C
Initial pressure = 700 mmHg
Final volume = ?
Final temperature = 273 k
Final pressure = 1 atm
Solution:
According to general gas equation:
P₁V₁/T₁ = P₂V₂/T₂
Solution:
<em>We will convert the mmHg to atm.</em>
700/760 = 0.92 atm
<em>and °C to kelvin.</em>
50+273 = 323 K
P₁V₁/T₁ = P₂V₂/T₂
V₂ = P₁V₁ T₂/ T₁ P₂
V₂ = 0.92 atm × 360 cm³ × 273 K / 323 K ×1 atm
V₂ = 290417.6 atm .cm³. K / 323 k. atm
V₂ =279.9 cm³
