Answer:
-2
Explanation:
Calcium is the element of second group and forth period. The electronic configuration of Calcium is - 2, 8, 8, 2 or 
There are 2 valence electrons of Calcium.
Thus, calcium loses two electrons to sulfate ion and sulfate ion accepts these electrons to form ionic bond.
Calcium sulfate, 
is formed when 2 valence electrons of calcium are loosed and they are gained by sulfate ion.
Thus, the charge on the sulfate ion is -2.
Answer:
a) The heat which we supply to water during boiling is used to overcome these forces of attraction between the particles so that they become totally free and change into a gas. This latent heat does not increase the kinetic energy of water particles and hence no rise in temperature takes place during the boiling of water.
b) Steam produces more severe burns than boiling water even though both are at 100oC because steam contains more heat, in the form of latent heat, than boiling water.
Explanation:
i hope this will help u
Answer:
But since the solubility product constant for each compound is provided, their relative solubility can be ranked from highest to lowest. Depending on the ranking above, it is evident that aluminum hydroxide Al(OH)3 A l ( O H ) 3 has the lowest solubility at 25 Celsius degreesAs temperature increases, its solubility increases as well. Notice, however, that it does not increase significantly. In fact, you can expect to be able to dissolve no more than 40 g of sodium chloride per 100 g of water at 80∘C
Explanation:
We have to find the number of moles of N₂ that are present in a sample that has a volume of 40.0 L at STP.
STP means Standard Conditions of Temperature and Pressure. These conditions are 273.15 K and 1 atm. We know that 1 mol of N₂ will occupy 22.4 L. We can use that ratio to find the answer to our problem.
1 mol of N₂ = 22.4 L
moles of N₂ = 40.0 L * 1 mol/(22.4 L)
moles of N₂ = 1.79 mol
Answer: 1.79 moles of nitrogen are present.
