When an iron is dipped in Copper Sulphate
Solution this reaction between them and
copper sulphate change into blue color to light
green color. This show that iron is more
reactive then copper, it can to replace copper
from CuSO4 , CuSO4 is of blue color and
FeSO4 is light green color.
Hope it helps
Answer:
Sr or Strontium
Explanation:
sr: strontium has atomic radius of 255pm
cu: copper has an atomic radius of 128pm
they teach you in chem how to do it based off the chart but I don't remember that method
Answer:

Explanation:
Hello.
In this case, since this is a system in which the water is heated up and the metal is cooled down in a calorimeter which is not affected by the heat lose-gain process, we can infer that the heat lost by the metal is gained be water, it means that we can write:

Thus, in terms of masses, specific heats and temperatures we can write:

Whereas the equilibrium temperature is the given final temperature of 28.4 °C and we can compute the specific heat of the metal as shown below:

Plugging the values in and since the density of water is 1.00 g/mL so the mass is 80.0g, we obtain:

Best regards!
Answer: X3+
Explanation:
Every atom aim to achieve stability by receiving electrons or giving their valence electrons in order to have a complete outermost shell of 2 (duplet) or 8 (octet structure).
In this case, the atom X will easily give off its three valence electrons to another atom(s), thereby forming a trivalent positive ion (X3+) with a stable duplet or octet structure (i.e an outermost shell with 2 or 8 electrons).
X --> X3+ + 3e-
Thus, due to the give away of three electrons (3e-), the atom X becomes X3+.
Answer:
So first thing to do in these types of problems is write out your chemical reaction and balance it:
Mg + O2 --> MgO
Then you need to start thinking about moles of Magnesium for moles of Magnesium Oxide. Based on the above equation 1 mole of Magnesium is needed to make one mole of Magnesium Oxide.
To get moles of magnesium you need to take the grams you started with (.418) and convert to moles by dividing by molecular weight of Mg (24.305), this gives you .0172 moles of Mg.
The theoretical yield would be the assumption that 100% of the magnesium will be converted into Magnesium Oxide, so you would get, based on the first equation, .0172 mol of MgO. Multiplying this by the molecular weight of MgO (24.305+16) gives us .693 g of MgO.
The percent yield is what you actually got in the experiment, and for this you subtract off the total mass from the crucible mass, or 27.374 - 26.687, which gives .66 g of MgO obtained.
Percent yield is acutal/theoretical, .66/.693, or 95.24%.
I'll let you do the same for the second trial, and average percent yield is just an average of the two trials percent yield.
Hope this helps.