Ar: What’s Your Mass?
What does Ar stand for in chemistry?
Relative Atomic Mass
What is the Mr of H₂O?
The Mr of H₂O is 18
(H = 1, O = 16, so 1 + 1 + 16 = 18).
What element has the Ar of 1
Hydrogen (H).
What is the Mr of H₂ (Hydrogen molecule)?
The Mr of H₂ is 2
(H = 1, so 1*2 = 2).
Where would you find the Ar of an element?
Looking at the number directly above the element symbol.
What is the Ar of oxygen (O)?
16
What is the Mr of NaCl?
The Mr of NaCl is 58.5
(Na = 23, Cl = 35.5, so 23 + 35.5 = 58.5).
Which element has the Ar of 40?
Calcium (Ca).
Calculate the Mr of HCl
The Mr of HCl is 36.5
(H = 1, Cl = 35.5, so 1 + 35.5 = 36.5).
How do you calculate the Mr of a compound?
The Mr is calculated by adding the Ar values of all the atoms in the formula, multiplied by the number of atoms of each element.
If an element has an Ar of 12, which element could it be?
Carbon (C)
What is the Mr of NH₃ (Ammonia)?
The Mr of NH₃ is 17
(N = 14, H = 1 → 14 + 1*3 = 17).
What is the Ar of Neon (Ne)?
The Ar of Neon is 20.
What is the Mr of MgF₂?
The Mr of MgF₂ is 62
(Mg = 24, F = 19 → 24 + 2*19 = 62)
If you have Na₂SO₄, what is its Mr?
The Mr of Na₂SO₄ is 142
(Na = 23, S = 32, O = 16 → 223 + 32 + 416 = 142).
If an element has an Ar of 20, which element could it be?
It could be Neon (Ne), since its Ar is 20.
Calculate the Mr of H₂SO₄
The Mr of H₂SO₄ is 98
(H = 1, S = 32, O = 16 → 12 + 32 + 164 = 98).
Which element has the Ar of 56?
Iron (Fe).
What is the Mr of CO₂?
The Mr of CO₂ is 44
(C = 12, O = 16 → 12 + 2*16 = 44).
What is the Mr of C₄H₁₀
The Mr of C₄H₁₀ is 58
(C = 12, H = 1 → 4x12 + 10x1 = 58).
If an element has an Ar of 222, which element could it be?
Radon
What is the Mr of C₆H₁₂O₆ (Glucose)?
The Mr of C₆H₁₂O₆ is 180
(C = 12, H = 1, O = 16 → 612 + 121 + 6*16 = 180).
What is the Ar of Lead (Pb)?
The Ar of Lead is 207.
Calculate the Mr of HNO₃
The Mr of HNO₃ is 63
(H = 1, N = 14, O = 16 → 1 + 14 + 3*16 = 63).
If a compound has the formula C₈H₁₀N₄O₂, what is its Mr?
The Mr of C₈H₁₀N₄O₂ is 194
(C = 12, H = 1, N = 14, O = 16 → 8x12 + 10x1 + 4x14 + 2x16 = 194).