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3 years ago

Convert 78.9 kJ into calories Can you also explain how pls? ty

Chemistry

1 answer:

Naddik [55]3 years ago

3 0

Explanation:

1 kJ = 238.85 cal and

1 cal = 0.004187 kJ

so it will be 78.9×238.85 = 18,844 calories

78.9 Kilojoules (kJ) = 18,844 Calories (IT) (cal)

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Consider a solution that is 0.05 M HCl. Your goal is to neutralize 1 L of this solution (i.e. bring the pH to 7). You also have

Ilia_Sergeevich [38]

Answer:

The volume of NaOH required is - 0.01 L

Explanation:

At equivalence point ,

Moles of $HCl$ = Moles of NaOH

Considering :-

$Molarity_{HCl}\times Volume_{HCl}=Molarity_{NaOH}\times Volume_{NaOH}$

Given that:

$Molarity_{NaOH}=5\ M$

$Volume_{NaOH}=?\ L$

$Volume_{HCl}=1\ L$

$Molarity_{HCl}=0.05\ M$

So,

$Molarity_{HCl}\times Volume_{HCl}=Molarity_{NaOH}\times Volume_{NaOH}$

$0.05\times 1=5\times Volume_{NaOH}$

$Volume_{NaOH}=\frac{0.05\times 1}{5}=0.01\ L$

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3 years ago

The pressure inside a compressed gas cylinder is 144 atm at 48°C. What will the pressure inside the cylinder be after it is cool

Andrews [41]

<h3>Answer:</h3>

134 atm

<h3>Explanation:</h3>

Based on the pressure law, the pressure of a gas varies directly proportionally to the absolute temperature at a constant volume.

Therefore; we are going to use the equation;

$\frac{P1}{T1}=\frac{P2}{T2}$

In this case;

Initial pressure, P1 = 144 atm

Initial temperature, T1 (48°C) = 321 K

Final temperature, T2 (25°C) = 298 K

We need to find the final pressure,

Therefore;

P2 = (P1/T1)T2

= (144/321)× 298 K

= 133.68 atm

= 134 atm

Therefore, the new pressure will be 134 atm.

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3 years ago

Explain why energy sources do not have 100% efficiency. Why do you think some have lower efficiencies?

bearhunter [10]

Answer:

Energy sources do not have 100% efficiency because the processes of energy conversion to usable forms involves energy losses.

Some have lower efficiencies due to; energy losses in form of heat during conversion, poor technology applied during conversion of energy and lack of desire equipment to use in the energy conversion system.

Explanation:

The desired form of energy for use is derived from conversion of energy from the source using an energy converter into another form which is usable. The efficiency of the energy converter is calculated as;

л = output energy/input energy

The efficiency of energy is limited to the cost of equipment required for conversion from energy source by the energy converter to a form which is usable. Additionally, because energy sources are scarce, the technology to use in energy conversion is a factor affecting energy efficiency in that high efficiency will require advanced technology with better equipment leading higher costs of that energy form. when heat losses are involved during energy conversion, efficiency lowers, thus its better if such losses are used as energy input in another system.

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3 years ago

Which of the following factors affects the strength of the gravitational force between two objects?

mash [69]

D. the distance between the objects

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3 years ago

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r-ruslan [8.4K]

<h2>Question:</h2>

A precipitate is a solid that sometimes forms when two liquids combine.