Answer:
Ex1 = 4.3 moles
Explanation:
for Ex 1
** Number of mole = Mass (g) / Molecular weight ' Mw' (g/mole)
for a = NaCl , first you must be calculate Mw = look to periodic table
Atomic weight for Na is 22.9 = 23 g and for Cl is 35.45 = 35 g
so Mw for NaCl = 23+35 = 58 g/mole
so Number of Moles for NaCl 250 g is
Number of Moles = 250 / 58 = 4.3 moles
do same for others ...
good luck ..
Answer:
A. increase
Explanation:
the smaller the size of the ionic compounds, the more closer they get packed together. This means electrostatic attraction also increases, which means the ionic bonds gets stronger...therefore increases the melting point
It would be a solar eclipse
Answer:
162g
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
2C2H6 + 7O2 —> 4CO2 + 6H2O
Next, we shall determine the number of mole of water, H2O produced by the reaction of 3 moles of C2H6.
This can be obtained as follow:
From the balanced equation above,
2 moles of C2H6 reacted to produce 6 moles of H2O.
Therefore, 3 moles of C2H6 will react to produce = (3 x 6)/2 = 9 moles of H2O.
Therefore, 9 moles of H2O is produced from the reaction.
Finally, we shall convert 9 moles of H2O to grams.
This can be done as shown below:
Molar mass of H2O = (2x1) + 16 = 18g/mol
Mole of H2O = 9 moles
Mass of H2O =..?
Mole = mass / molar mass
9 = mass of H2O /18
Cross multiply
Mass of H2O = 9 x 18
Mass of H2O = 162g
Therefore, 162g of H2O were produced from 3 moles of C2H6.
