Hey there!
Atomic number is the number of protons.
Atomic mass is the sum of protons and neutrons.
9 + 11 = 20
Your answer is B) The atomic number is 9 & the atomic mass is 20.
Hope this helps!
Answer:
- 2K(s) + (1/8) S₈ (s) + (3/2) O₂(g) → K₂SO₃ (s)
Explanation:
The<em> standard enthalpy of formation </em>of a substance is the change in enthalpy that happens when one mole of the substance is formed from the elements in their standard states.
Thus, to calculate the standard state of formation of a compound you must:
- 1. Identify the elements that form the compound
- 2. Identify the standard form of each element
- 3. Set the equation to form one mole of the compound, which may require to use fractional coefficients for some of the elements.
Applying that to our compound K₂SO₃
<u>1. Elements:</u>
- potassium, K;
- sulfur, S; and
- oxygen, O.
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<u>2. Standard forms of the elements:</u>
- potassium: solid, K(s)
- sulfur: solid, octatomic molecules, S₈ (s)
- oxygen: diatomic gas, O₂(g)
<u>3. Reaction:</u>
- K(s) + S₈ (s) + O₂(g) → K₂SO₃ (s)
Balance, keeping one mole of K₂SO₃. You will need to use fractional coefficients for some elements:
- 2K(s) + (1/8) S₈ (s) + (3/2) O₂(g) → K₂SO₃ (s) ← answer
Answer:
A. 2-pentyne is the answer.
It's important to understand your three states of matter because it helps you understand your surrounding and also what things change shape and why and what things stay the same and why.
Answer: D, splitting water into hydrogen and oxygen is a chemical change.
