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professor190 [17]
3 years ago
7

Help me please !! is it A,B,C, or D ???

Chemistry
1 answer:
Nata [24]3 years ago
5 0
Ok, after doing an immense amount of research I came up with the most logical answer.

A. Is indicated by a negative enthrall sign.

Reasoning: an endothermic reaction is ice melting and the energy being more than its surroundings. Not specified to ice but as an example, ice is endothermic. That puts d and b out of the running leaving you left with a and c.

When I searched up enthalpy, it said “When a substance changes at constant pressure, enthalpy tells how much heat and work was added or removed from the substance.” Which is similar to c, right? Yeah, meaning both a and c are similar in that aspect.

The reason I decided to go with a is because heat is NOT released into the surrounding, exothermic reactions release energy and heat into the surrounding.
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Calculate the number of kilojoules to warm 125 g of iron from 23.5 °C to 78.0 °C.
insens350 [35]
Given:
Iron, 125 grams T
1 = 23.5 degrees Celsius, T2 = 78 degrees Celsius.  

Required:
Heat produced in kilojoules  

Solution:
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<span>
Q (heat) = nRT = nR(T2 = T1)</span>
Q (heat) = 2.24 moles (8.314 Joules per mol degrees Celsius) (78.0 degrees Celsius – 23.5 degrees Celsius)
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3 years ago
A race car is driven by a professional driver at 99 . What is this speed in and ? 1 mile = 1.61 kilometers 1 hour = 60 minutes E
slavikrds [6]

Answer: The speed is equivalent to <u>159.39 kilometers per hour </u>or <u>2.65 kilometers per minute.</u>

Explanation:

Given, The speed of a race car = 99 miles/ hour

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Also, 1 hour = 60 minutes

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Hence, the speed is equivalent to <u>159.39 kilometers per hour </u>or <u>2.65 kilometers per minute.</u>

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