When cooled by liquid nitrogen, the balloon shrinks (not as much as the air-filled balloon) and it sinks down on the table. When heating up, the balloon slowly rises and flies up in the air again. Explanation 1: The volume of the balloon decreases by the low temperature, because the gas inside is cooled down.
Answer:
The mass of coke needed to react completely with 1.0 ton of copper(II) oxide is 0.794 Ton.
Explanation:

1 Ton = 907185 grams
Mass of copper oxide = 1.0 Ton = 907185 grams
Moles of copper oxide =
According to reaction, 2 moles of copper oxide reacts with 1 mole of carbon.
Then 11403.95 moles of copper oxide will react with:
of carbon
Mass of 5,701.98 moles of carbon:

Mass of coke = x
Mass of carbon = 68,423.75 g
Percentage of carbon in coke = 95%


The mass of coke needed to react completely with 1.0 ton of copper(II) oxide is 0.794 Ton.
Answer:
It will be denatured.
Explanation:
Salivary amylase works best at pH 6.8.
At pH 2.5, its activity will decrease enormously as it becomes denatured by the high acidity of the stomach contents.
It has to be understood that 2 moles of oxygen are there in each mole of PbO2. Then it has to be calculated for 2 moles of oxygen.
Amount of oxygen = 2 * 5.43 moles
= 10.86 moles
Now it is also a fact that each mole of H2O contains 1 mole of oxygen. Then it can be easily concluded that 10.86 moles of water will be produced. I hope the procedure is clear enough for you to understand.