The correct option is C.
An atom can be either in the ground state or in an excited state. An atom is said to be in the ground state, if the total energy of its electron can not be lowered by moving one or more electrons into different orbitals. At the ground state, the electrons in the atom have the lowest energy possible and they are stable. On the other hand, an atom is said to be in an excited state, if the energy of its electrons can be lowered by transferring one or more electrons into different orbitals. An atom in an excited state has more energy and is less stable.
Answer:
A planet's orbital speed changes, depending on how far it is from the Sun. The closer a planet is to the Sun, the stronger the Sun's gravitational pull on it, and the faster the planet moves. The farther it is from the Sun, the weaker the Sun's gravitational pull, and the slower it moves in its orbit.
Answer:
Molarity of Na₂CO₃ = 0.25M
% mass = 2.69
Explanation:
Molarity means mole of solute in 1L of solution
Molar mass of solute (Na₂CO₃) = 105,98 g/m
Moles = mass / molar mass → 6.73 g / 105.98 g/m = 0.0635 m
Mol/L = [M]
0.0635 mol/0.250L = 0.25M
Density of solution = Solution mass / Solution volume
1 g/ml = Solution mass / 250 mL → Solution mass is 250g
% mass will be:
In 250 g of solution we have 6.73 g of solute
in 100 g of solution we have (100 . 6.73)/250 = 2.69
Answer is: mass of water is 1,35 grams.
Chemical reaction: 2H₂ + O₂ → 2H₂O.
m(H₂) = 9,5 g.
n(H₂) = m(H₂) ÷ M(H₂).
n(H₂) = 9,5 g ÷ 2 g/mol.
n(H₂) = 4,75 mol.
m(O₂) = 1,2 g.
n(O₂) = 1,2 g ÷ 32 g/mol.
n(O₂) = 0,0375 mol; limiting reactant.
From chemical reaction: n(O₂) : n(H₂O) = 1 : 2.
n(H₂O) = 0,0375 mol · 2 = 0,075 mol.
m(H₂O) = 0,075 mol · 18 g/mol.
m(H₂O) = 1,35 g.
Answer:
Mass % of hydrogen = 20.9 %
Explanation:
Given data:
Mass of hydrogen = 0.485 g
Mass of water = 2.32 g
Mass percent of hydrogen = ?
Solution:
Mass % of hydrogen = mass of hydrogen / mass of water × 100
Mass % of hydrogen = 0.485 g/ 2.32 g × 100
Mass % of hydrogen = 0.209 × 100
Mass % of hydrogen = 20.9 %
