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Zanzabum
3 years ago
12

A certain atom has an atomic number of four. how many protons does it have? 8 2 0 4 description

Chemistry
2 answers:
Contact [7]3 years ago
4 0
4 protons the number of proton has the same number of electron [which is the same as atomic number]
const2013 [10]3 years ago
3 0
4 protons the number of proton has the same number of electron
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the heat of fusion of acetone is 5.7 kJ/mol. Calculate to two significant figures the entropy change when 6.3 mol of acetone mel
shtirl [24]

<u>Answer:</u> The entropy change of the process is 2.0\times 10^2J/K

<u>Explanation:</u>

To calculate the entropy change for different phase at same temperature, we use the equation:

\Delta S=n\times \frac{\Delta H_{f}}{T}

where,  

\Delta S = Entropy change

n = moles of acetone = 6.3 moles

\Delta H_{f} = enthalpy of fusion = 5.7 kJ/mol = 5700 J/mol    (Conversion factor:  1 kJ = 1000 J)

T = temperature of the system = -94.7^oC=[273-94.7]=178.3K

Putting values in above equation, we get:

\Delta S=\frac{6.3mol\times 5700J/mol}{178.3K}\\\\\Delta S=201.4J/K=2.0\times 10^2J/K

Hence, the entropy change of the process is 2.0\times 10^2J/K

4 0
3 years ago
Which explains the information needed to calculate speed and velocity?
USPshnik [31]

Answer:

Both require time, but velocity requires displacement and speed requires distance

Explanation:

For calculating speed we require time and distance because speed is defined as the distance per unit time and as speed is a scalar quantity it does not have any direction

But for calculating the velocity we require time as well as displacement because velocity is defined as the displacement per unit time and as velocity is a vector quantity it has direction

Displacement is the shortest distance between the initial position and the final position and it has a specified direction as well

8 0
3 years ago
Read 2 more answers
Which of the following is an empirical formula? a) H2O2 b) H2O c) C2H2 d) C4H8
Alex_Xolod [135]
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3 0
2 years ago
A kayak travels in a lake at an average speed of 35 m/min. If the perimeter of the lake
DanielleElmas [232]

Answer: 4 hours

Explanation:

It takes the kayak 1 minute to travel 35 meters.

Divide the total (8400m) by the amount of meters per minute (35m)

\frac{8400m}{35m} =240minutes

Now convert into hours. (Remember that 1h has 60min)

240min(\frac{1h}{60min})=4h

6 0
3 years ago
Different "substances" are forms of matter (having volume and taking up space) with different _______________ from each other. a
ExtremeBDS [4]

Answer:

properties

Explanation:

The properties of matter are the various ways in which matter behaves under certain circumstances.

Various substances have different volumes and shapes. These differences account for the various properties of matter.

3 0
3 years ago
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