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3 years ago

Someone please help.

Chemistry

1 answer:

Yuri [45]3 years ago

6 0

17. ΔH rxn is the enthalpy of a reaction. It is the amount of energy or heat absorbed in a reaction. If enthalpy is positive, it means the reaction absorbs heat, which means it is endothermic. If the enthalpy is negative, it means the reaction release heat, which means it is exothermic.

18. yes, it is possible in theory but it is not necessary. Water is the ideal, cheaper, and most abundant liquid for a calorimeter.

19. Specific heat= heat/mass*Temp. the mass is already known You can place the piece of metal in a calorimeter filled with water. the piece of metal and water must be at different temperatures. Ideally, you would heat up the water and let it cool down. This change in temperature in the temperature that goes into the formula for the piece of metal. The only missing value is the heat which can be easily calculated because water' specific heat is known which can be used to calculate the heat loss by the water, which is the same as the heat gain by the piece of metal. With all the three values calculated and measured, you can simply plug them into the formula and solve for the specific heat of the metal.

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What is the weight of a 90kg man standing on the moon, where gmoon = 1.64 m/s2?

Doss [256]

Answer:

The weigth of a 90kg man standing on the moon is 147.6 N (option C)

Explanation:

Weight is called the action exerted by the force of gravity on the body.

The mass (amount of matter that a body contains) of an object will always be the same, regardless of where it is located. Instead, the weight of the object will vary according to the force of gravity acting on it.

The formula that allows you to calculate the weight of any body is:

W = m*g

where:

W = weight measured in N.
m = mass measured in kg.
g = acceleration of gravity measured in m/s². The acceleration of gravity g is the same for all objects that fall due to gravitational attraction, whatever their size or composition. For example, as an approximate value on Earth, g = 9.8 m/s².

In this case, the mass m has a value of 90 kg and the gravity g has a value of 1.64 m/s², which is the value of the acceleration of gravity of the moon. Then:

W=90 kg* 1.64 m/s²

W= 147.6 N

Finally, the weigth of a 90kg man standing on the moon is 147.6 N (option C)

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3 years ago

Why do you think some of the indicators used in experiment 2 were different than the ones used in experiment 1?

pentagon [3]

During selection of indicator. We choose an indicator which have pH range equivalent to the pH change of reaction to give better result and better observation.

So there are some different indicator are used in table 2 as compared to the table 1.

- Alizarin and phenolphthalein are basic indicator and their pH range is more than 8 so they are used in table 2

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7. Which of the following is a chemical property?

Goryan [66]

Answer:

It ability to react with oxygen.

Explanation:

Freezing point and hardness can be altered. Physical properties can also be reversed. Chemical properties on the other hand cannot. The product after reaction with an element never changes.

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3 years ago