"Physical changes occur when objects or substances undergo a change that does notchange their chemical composition. This contrasts with the concept of chemical change in which the composition of a substance changes or one or more substances combine or break up to form new substances."
Answer:
15.5 gm
Explanation:
What is the mass of phosphorus that contains twice the number of atoms found in 14 g of iron?
[Relative atomic mass : P = 31; Fe = 56]
14 gm Fe = 14gm/ 56 gm/mole = 14 mole gm/56gm = 14/56 mole
0.25 moles
2 X 0.25 = 0.5 moles
1 mole P = 31 gm
so
0.5 moles P =31/2 =15.5 gm
Calculate the ratio by using Henderson-Hasselbalch equation:
pH = pKa + log [neutral form] / Protonated form
3.05 = 2.21 + log [neutral form] / [Protonated form]
3.05 - 2.21 = log [neutral form] / [Protonated form]
0.84 = log [neutral form] / [Protonated form]
[neutral form] / [protonated form] = anti log 0.84 = 6.91
Answer:
P₂ = 140 KPa
Explanation:
Given data:
Initial volume = 8.0 L
Final volume = 4.0 L
Initial pressure = 70 KPa
Final pressure = ?
Solution:
According to Boyle's law
P₁V₁ = P₂V₂
P₂ = P₁V₁ / V₂
P₂ = 70 KPa ×8.0 L/4.0 L
P₂ = 560 KPa .L / 4.0 L
P₂ = 140 KPa
