Let the mass of KMnO 4 required to produce two bottles of oxygen be x.
Mass of two bottles of oxygen: m = ρ v = 0.25l *1.43g/l = "0.3575g?"
3 16 32
X 0.3575g
?
x = " 3.53g " & lt7g？
A: Seven grams of KMnO 4 can produce 250 ml of oxygen.
Solution 2:
Let the mass of oxygen produced by 7 grams of KMnO 4 be X.
3 16 32
7g x
x="0.7 1g？"
v = m/ρ= 0.7 1g/( 1.43g/L)≈0.5l = 500ml > 250ml？
A: Seven grams of KMnO 4 can produce 250 ml of oxygen.
(2)①A (2 points)? ②A, C(2 points) (65438+ 0 point for a correct answer, no points will be deducted for a wrong answer)
③ Because the air pressure in the bottle is greater than the outside air pressure.
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