Answer:
A
Explanation:
A chemical change is when a new substance is created, which often has its own chemical properties, so A is the correct answer.
Idk it’s making me answer a question in order to get help on my own
Answer : Hg (Mercury)
Explanation : In the given series of elements Na falls after the Cu in the reactivity series, for Pb it also falls after Cu, and for Mg it is the same.
Only Hg which is mercury can spontaneously donate its electrons to copper in the solution because it falls before Cu in the reactivity/activity series.
Answer:
Gram
Explanation:
The SI unit of mass is grams.
Mass is the measure of matter contained in a substance. It is usually determined by weighing an amount of substance on a balance or scale.
- Mass is a fundamental quantity
- So, the unit of mass is grams.
- Ounce and pounds are other units but not the standard one.
- Newton is the unit of force and weight.
Given the temperature 746 K and activity of Pb equal to 0.055. The mole fraction of Pb is 0.1. So, the mole fraction of Sn = 0.9.Activity coefficient, γ = 0.055 / 0.1 = 0.55.The expression for w=ln〖γ_Pb x RT〗/(X_Sn^2 )=(-0.5978 x 8.314 J/(mol K ) x 746 K)/(0.9 x 0.9)= -4577.7 J= -4578 J
Now we use the computed value above and new temperature 773 K. The mole fraction of Sn and Pb are 0.5 and 0.5 respectively. Calculate the activity coefficient in the following manner.lnγ_Sn=w/RT X_Pb^2=(-4578 J)/(8.314 J/mol x 773 K) x 0.5 x 0.5= -0.718lnγ_Sn=exp(-0.178)=0.386The activity of Sn= γ_Sn x X_Sn=0.386 x 0.5=0.418
w of the system is -4578 J and the activity of Sn in the liquid solution of xsn at 500 degree Celsius is 0.418
