I wanna say it's B... I hope I could help you; apologies if I'm incorrect.
Explanation:
Molar mass
The mass present in one mole of a specific species .
The molar mass of a compound , can easily be calculated as the sum of the all the individual atom multiplied by the number of total atoms .
(a) )hydrogen fluoride, HF
Since ,
Molar mass of of the atoms are -
Hydrogen , H = 1 g/mol
Fluorine, F = 19 g/mol.
Molar mass of HF = ( 1 g/mol ) + ( 19 g/mol ) = 20 g/mol.
(b) ammonia, NH₃
Molar mass of of the atoms are -
nitrogen, N = 14 g/mol
and Hydrogen , H = 1 g/mol
Molar mass of NH₃ = 14 + ( 3 x 1 ) g/mol = 17 g/mol.
(c) nitric acid , HNO₃
Molar mass of of the atoms are -
oxygen , O = 16 g/mol.
Hydrogen , H = 1 g/mol
nitrogen, N = 14 g/mol
Molar mass of HNO₃ = (1 g/mol ) + ( 14 g /mol) + ( 3 x 16 ) = 63 g/mol.
(d)Silver sulfate, Ag₂SO₄
Molar mass of of the atoms are -
silver, Ag = 108 g/mol
sulfur, S = 32 g/mol.
oxygen , O = 16 g/mol.
molar mass of Ag₂SO₄ = ( 2 x 108 g/mol ) + ( 32 g /mol )+ (4 x16 g/mol )
=312 g/mol.
(e )boric acid , B(OH)₃
Molar mass of of the atoms are -
boron , B = 11 g/mol
oxygen , O = 16 g/mol.
Hydrogen , H = 1 g/mol
Molar mass of B(OH)₃ = ( 11 ) + ( 3x16 ) + ( 3 x 1 ) = 62 g/mol.
Answer:
Because the sugar flour and eggs can no longer be separated. The properties of the materials have changed so it's a chemical change
Answer:
1.195 g of Arsenic.
Explanation:
Equation of the reaction:
Ga(l) + As(s) → GaAs(s).
Calculating the limiting reagent by:
Number of moles of:
Gallium:
Molar mass of Gallium = 69.7 g/mol.
Mass = 4 g
Number of moles = mass/molar mass
= 4/69.7
= 0.0574 mol.
Arsenic:
Molar mass of Arsenic = 75 g/mol.
Mass = 5.5 g
Number of moles = mass/molar mass
= 5.5/75
= 0.0733 mol
Therefore, using stoichiometry since 1 mole of Gallium reacted with 1 mole of Arsenic. The limiting reagent is Gallium.
Excess reagent is Arsenic.
Number of moles excess = 0.0733 - 0.0574
= 0.0159 moles
Mass of the excess Arsenic left =
Molar Mass * number of moles
= 0.0159 * 75
= 1.195 g of Arsenic.
Varuable, In algebra, a symbol (usually a letter) standing in for an unknown numerical value in an equation :)