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dybincka [34]
3 years ago
8

A chemical reaction gives off 1,500 kj of heat energy. about how many calories is this? (1 calorie = 4.18 joules)

Chemistry
2 answers:
Greeley [361]3 years ago
6 0
1500kj = 15x 10^5 j
1 calorie = 4.18 j
(15 x 10^5)/4.18= 3.58 x 10^5

Answer is a
Zanzabum3 years ago
3 0

Answer is: a. 3.6 x 10^5 calories.  

E = 1500 kJ; heat energy.

E = 1500 kJ · 1000 J/kJ.

E = 1500000 J = 1.5·10⁶ J.

E = 1.5·10⁶ J ÷ 4.18 J/cal.

E = 3.6·10⁵ cal.

Calorie (cal), or small calorie, is the amount of energy needed to heat one gram of water by one degree Celsius.

One small calorie is approximately 4.18 joules.

A calorie is a unit of energy.


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Xelga [282]

Answer:

1. B.10 mol/l

2. D.

3.A.

Explanation:

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7 0
2 years ago
How many moles of methane (CH4) are in 7.31 x 10^25 molecules
Ivan

molar mass of methane CH4

= C + 4 H  

= 12.0 + 4 x 1.008

= 12.0 +  4.032

= 16.042g/mol

7.31 x 10^25 molecules x <u>             1 mole  CH4    </u>  = 121.43 moles

                                       6.02 x 10^23 CH4 molecules

121.43 moles CH4 are present.

       


6 0
2 years ago
Read 2 more answers
Select the correct answer from each drop-down menu.
earnstyle [38]

Answer:

The granite block transferred <u>4080 joules</u> of energy, and the mass of the water is <u>35.84 grams</u>.

Explanation:

The equation needed to answer both parts of the question is:

Q = mcΔT

In this equation,

-----> Q = energy/heat (J)

-----> m = mass (g)

-----> c = specific heat (J/g°C)

-----> ΔT = change in temperature (°C)

<u>Part #1:</u>

First, you need to find the energy transferred from granite block using the previous equation. You have been given the mass, specific heat, and change in temperature.

Q = ? J                            c = 0.795 J/g°C

m = 126.1 g                     ΔT = 92.6 °C - 51.9 °C = 40.7 °C

Q = mcΔT

Q = (126.1 g)(0.795 J/g°C)(40.7 )

Q = 4080

<u>Part #2:</u>

Secondly, using the energy calculated in Part #1, you need to calculate the mass of the water. You have calculated the energy transferred, and have been given the specific heat and change in temperature.

Q = 4080 J                     c = 4.186 J/g°C

m = ? g                            ΔT = 51.9 °C - 24.7 °C = 27.2 °C

Q = mcΔT

4080 J = m(4.186 J/g°C)(27.2 °C)

4080 J = m(113.8592)

35.84 = m

4 0
2 years ago
Be sure to answer all parts.
Liula [17]

A. The patch's area in square kilometers (km²) is 1.61×10⁻⁹ km²

B. The cost of the patch to the nearest cent is 734 cents

<h3>A. How to convert 16.1 cm² to square kilometers (km²)</h3>

We can convert 16.1 cm² to km² as illustrated below:

Conversion scale

1 cm² = 1×10⁻¹⁰ km²

Therefore,

16.1 cm² = 16.1 × 1×10⁻¹⁰

16.1 cm² = 1.61×10⁻⁹ km²

Thus, 16.1 cm² is equivalent to 1.61×10⁻⁹ km²

<h3>B. How to determine the cost in cent</h3>

We'll begin by converting 16.1 cm² to in². This can be obtained as illustrated below:

1 cm² = 0.155 in²

Therefore,

16.1 cm² = 16.1 × 0.155

16.1 cm² = 2.4955 in²

Finally, we shall the determine the cost in centas fo r llow:

  • Cost per in² = $2.94 = 294 cent
  • Cost of 2.4955 in² =?

1 in² = 294 cent

Therefore,

2.4955 in² = 2.4955 × 294

2.4955 in² = 734 cents

Thus, the cost of the patch is 734 cents

Learn more about conversion:

brainly.com/question/2139943

#SPJ1

6 0
1 year ago
Someone pls help me I will mark you as brain
Reptile [31]
3rd one I think it is.
5 0
2 years ago
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