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3 years ago

Why are atomic masses on the Periodic Table written in decimals when they are based on mass numbers that can be whole numbers?

1 answer:

8 0

To allow for equations and problems in chemistry to be as precise as possible. When experiments are conducted, and even if the number is the slightest bit off, the problem or experiment could be impacted very negatively. It allows for complete accuracy to ensure nothing goes wrong, since chemistry is very touchy and risky when dealing with extremely unsafe elements.

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Which of the following will change the momentum of a moving object?

valkas [14]

All correct except last option because instantaneous change in acceleration does not change the velocity.

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4 years ago

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A 0.875-g sample of anthracite coal was burned in a bomb calorimeter. The temperature rose from 22.50 to 23.80°C. The heat capac

kherson [118]

Answer:

a) 26.65 kJ was the heat evolved by the reaction.

b) $3.046\times 10^7 kJ$ is the energy released on burning 1 metric ton of this type of coal

Explanation:

Heat capacity of the calorimeter = C = 20.5 kJ/°C

Initial temperature of the calorimeter, $T_1$ = 22.50°C

Final temperature of the calorimeter, $T_2$ = 23.80°C

The heat evolved by the reaction = Q

$Q=C(T_2-T_1)$

$Q=20.5 kJ/^oC\times (23.80^oC-22.50^oC)$

$Q=26.65 kJ$

26.65 kJ was the heat evolved by the reaction.

0.875 g sample of anthracite coal was burned in a bomb calorimeter

0.875 g sample of anthracite coal gives 26.65 kJ of heat.

1 metric ton= 1000 kg

1000 kg = 1000 × 1000 g = 1,000,000 (1 kg =1000 g)

Then burning 1,000,000 g coal will give:

$=\frac{26.65 kJ }{0.875}\times 1,000,000 g=3.046\times 10^7 kJ$

$3.046\times 10^7 kJ$ is the energy released on burning 1 metric ton of this type of coal

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3 years ago

Would you expect hydrogen chloride to be a gas, a liquid or a solid, at room temperature and pressure? Explain your answer

Vlada [557]

At room temperature hydrogen chloride is a colorless gas with a sharp or pungent odor. Under pressure or at temperatures below –85°C (-121°F), it is a clear liquid.

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3 years ago

What is happening to the temperature of the substance BEFORE AND AFTER the phase changes?

Neporo4naja [7]

First off, you must realize that the phase changes are marked by the points B and D on the graph. They are level because all of the energy (or heat) being added is being consumed by the physical process. So The temperature is increasing before the phase change, and after the phase change. The moments before and after are represented by points A, C, and E.

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3 years ago

Balance each equation and identify the reaction types.

Paladinen [302]

Answer:

Look up an equation balancer online some will also tell you the reaction type

Explanation:

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3 years ago