Answer: last one is right
Explanation: atoms of same element have always same number of protons but may have several isotopes which have different number of neutrons.
Answer: concentration in Molarity it's actually Molarity
Molarity=concentration/molar mass
Concentration=50g/0.3dm³=166.67g/dm³
Molar mass=180g/mol
Molarity=0.926mol/dm³
The mass of silver metal produced from 6.35g of copper is 21.574 grams
calculation
Cu + 2AgNO3 → Cu(NO3)2 +2 Ag
find the moles of Cu used = mass/molar mass of Cu
moles = 6.35/63.5 =0.1 Moles
by use of mole ratio between Cu to Ag which is 1:2 the moles of Ag is therefore= 0.1 x2= 0.2 moles
mass of Ag = moles x molar mass
= 0.2 moles x 107.87 g/mol = 21.574 grams
Answer:
C4H4O
Explanation:
1.24 g x 1mol/(44)g = 0.03mol C;
Mass of C: 0.03mol x 12.g/1mol
= 0.36g of C
mol of H: 0.255g x 1mol /(18) x2= 0.028mol
Mass of H; = 0.028g × 1 of H
Mass of O: 0.519 g – (0.36g +0.028g)= 0.131g;
0.131g/16 =0.008 mol
Divide by the smallest number of moles;
0.028/0.008 mol = 3.5; 0.03/0.008 mol =3.75, 0.008 mol/0.008 mol =1
C4H4O