Answer: 7.90 g/cm^3
Explanation:
Density = Mass / Volume
The first step is to find the volume by multiplying the three measures of the cube that have been provided.
3.50 x 0.755 x 2.25 = 5.95 cm^3
Now we can plug the numbers into our equation.
Density = 47.0g / 5.95 cm^3
Density = 7.90 g/cm^3
Answer: 0.25
Explanation: M = moles of solute / volume of solution (L)
First, you need to calculate the number of moles using the given mass and the molar mass.
15 g74.692 g/mol≈0.20 mol
Then, you can solve for molarity using the molarity equation. The answer should be reported to two significant figures.
M=0.20 mol/ 0.800 L = 0.25 M
The threshold frequency of Cesium is 5.2 x 10^14 Hz.
To find the frequency of yellow light, we use the equation:
speed of light = wavelength x frequency
3 x 10^8 = 5.8 x 10^-17 x frequency
frequency = 5.17 x 10^24
This is higher than the threshold frequency of Cesium, thus, electrons will be emitted.
Given question is incomplete. The complete question is as follows.
Pentaborane (
) is a colorless highly reactive liquid that will burst into flames when exposed to oxygen.the reaction is:
Calculate the kilojoules of heat released per gram of the compound reacted with oxygen.the standard enthalpy of formation 
, 
, and 
are 73.2, -1271.94, and -285.83 kJ/mol, respectively.
Explanation:
As the given reaction is as follows.
Therefore, formula to calculate the heat energy released is as follows.
Hence, putting the given values into the above formula is as follows.
= 
= -9078.59 kJ/mol
Since, 2 moles of Pentaborane reacts with oxygen. Therefore, heat of reaction for 2 moles of Pentaborane is calculated as follows.
= -71.915 kJ/g
Thus, we can conclude that heat released per gram of the compound reacted with oxygen is 71.915 kJ/g.
