(2011 Zhejiang Taizhou, 36 questions) in the nature of oxygen and the preparation of the test, need to complete the carbon and iron wire combustion in oxygen two experiments, the experiment booklet su

Set the generation of two bottles of oxygen need to KMnO 4 quality of x

Two bottles of oxygen mass: m = ρV = 0.25 liters * 1.43g / liter = "0.3575g?"

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x 0.3575g<

x="3.53g" < 7g

Answer: 7 grams of KMnO 4 makes 250 milliliters of oxygen.

Solution 2:

Let the mass of oxygen that can be produced from 7 grams of KMnO 4 be x

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7g x

?

x="0.71g"

V=m/ρ=0.71g/(1.43g/liter) ≈ 0.5 liters = 500 ml> 250 ml?

Answer: 7 grams of KMnO 4 produces 250 milliliters of oxygen.

(2) ①A (2 points)? (2) A, C (2 points) (1 point for a correct answer, no points for a wrong answer)

③ Because the air pressure inside the bottle is greater than the outside air pressure