1. Explain the main reason why metal rusting happens?
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A. Metal rusting happens because of sunlight.
B. Metal rusting happens because of the presence of oxygen.
C. Metal rusting happens because metal supplies iron and water.
D. Metal rusting happens because of the presence of oxygen in the air that reacts on metal.
2. Differentiate choices A-D. Why do you think sliced apples turn brown?
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A. Because it is delicious and nutritious.
B. Because it is colorful and fresh, it reacts with oxygen and iron.
C. Because it contains an enzyme that reacts with oxygen and iron-containing phenols that are also found in the apple.
D. All the above statements are correct.
3. Compare the given statements below. Which of them is NOT true?
A. Peaches contain an enzyme called polyphenol oxidase.
B. When you slice, open or bite the fruits, this enzyme reacts with oxygen in the air and iron-containing phenols that are also found in the fruit.
C. This oxidation reaction causes a sort of rust to develop on the surface of the fruits.
D. You will not notice browning whenever an apple or banana is cut because these actions will not damage the cells in the fruit.
4. In your candle burning experiment, lighted-candle in the smallest jar went out the shortest time. What does this imply?
A. Oxygen in the air is enough.
B. Oxygen is not necessary to create fire.
C. Carbon dioxide is needed to create fire.
D. There is more oxygen needed to continue burning.
5. What happens to sugar when added with water and heat is applied?
A. When sugar is heated, it turns into ice.
B. When sugar is heated, it turns into solid.
C. When sugar is heated, it melts and turns into syrup.
D. When sugar is heated, it changes its color and taste
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Answer:
1.) C. Metal rusting happens because metal supplies iron and water
2.) D. All the above statements are correct.
3.) B. When you slice, open or bite the fruits, this enzyme reacts with oxygen in the air and iron-containing phenols that are also found in the fruit.
4.) A. Oxygen in the air is enough.
5.) When sugar is heated, it melts and turns into syrup.
Hope it helps!! :DD