Answer:
40.4 kJ
Explanation:
Step 1: Given data
- Heat of sublimation of CO₂ (ΔH°sub): 32.3 kJ/mol
Step 2: Calculate the moles corresponding to 55.0 g of CO₂
The molar mass of CO₂ is 44.01 g/mol.
n = 55.0 g × 1 mol/44.01 g = 1.25 mol
Step 3: Calculate the heat (Q) required to sublimate 1.25 moles of CO₂
We will use the following expression.
Q = n × ΔH°sub
Q = 1.25 mol × 32.3 kJ/mol = 40.4 kJ
I’m pretty sure it’s sulphur dioxide
Taking into account the definition of molarity, the concentration of the solution is 0.855 .
<h3>Definition of molarity</h3>
Molar concentration or molarity is a measure of the concentration of a solute in a solution and indicates the number of moles of solute that are dissolved in a given volume.
The molarity of a solution is calculated by dividing the moles of solute by the volume of the solution:
Molarity is expressed in units .
<h3>Molarity of NaCl</h3>
In this case, you have:
- number of moles of NaCl= 1.71 moles (being 58.45 g/mole the molar mass of NaCl)
- volume 2 L
Replacing in the definition of molarity:
Solving:
Molarity= 0.855
Finally, the concentration of the solution is 0.855 .
Learn more about molarity:
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Answer:
Selenium
Explanation:
One way to figure this out is to count the electrons and add them up.
2+2+6+2+6+2+10+4 = 34 electrons
A neutral atom has the same number of electrons and protons. Protons tell us the atomic number of an element. Element number 34 is Selenium.
Another way to figure it out is to look at just the highest "s" or "p" level of the electron configuration, and then see which element corresponds to that. This element has a 4s and a 4p, so I will look at 4p. The configuration is 4p4, so I will look at the 4th row of the periodic table (4p4) in the "p" block (4p4) and the 4th element in the "p" block (4p4). That's selenium :)