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Discovered by the Chinese in the 9th century, black powder is a mixture of potassium nitrate, carbon, and sulfur. These three substances are the reactants in the chemical reaction that causes fireworks to explode.
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When black powder burns, energy is released as heat and light. This reaction is exothermic.
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The correct answer is B: Exothermic because energy is released as reactants are converted to products.
Fill in the blank to complete the sentences. Not all answer choices will be used.
Discovered by the Chinese in the 9th century, black powder is a mixture of potassium nitrate, carbon, and sulfur. These three substances are the
in the chemical reaction that causes fireworks to explode.
2
Fill in the blanks to complete the sentences. Not all answer choices will be used.
When black powder burns,
is released as heat and light. This reaction is
.
3
This diagram shows the energy changes during the chemical reaction that causes a firework to explode. Is the reaction exothermic or endothermic?
A line graph showing the change in stored energy over time during a chemical reaction. The y-axis shows stored energy, and the x-axis shows time. The graph starts with a flat line representing the reactants, then increases to a peak called the activation energy, and then decreases to a flat line representing the products. An arrow points up from the reactants to the activation energy and is labeled "Activation energy (in)", an arrow points down from the activation energy to the products, and a horizontal dashed line shows the energy level of the reactants and a dashed line shows the energy level of the products. The products have lower stored energy than the reactants.
A
Exothermic because the products store more energy than the reactants
B
Exothermic because energy is released as reactants are converted to products
C
Endothermic because the products store less energy than the reactants
D
Endothermic because energy is absorbed as reactants are converted to products
1 answer
1 answer