Answer:- d) 42 kJ of heat is released and the reaction is exothermic.
Solution:- Heat of reaction is the summation of heats of products - reactants.
![\Delta H_r_x_n=\sum [products-reactants]](https://tex.z-dn.net/?f=%5CDelta%20H_r_x_n%3D%5Csum%20%5Bproducts-reactants%5D)
From given information, the energy contained by products is 352 kJ and the energy contained by reactants is 394 kJ. Let's plug in the values in the formula:
= [352 kJ - 394 kJ]
= -42 kJ
Heat of reaction is -42 kJ. The negative sign indicates the heat is released means the reaction is exothermic.
So, the correct option is the last one, 42 kJ of heat is released and the reaction is exothermic.
Answer:
To find the noble gas notation, you first take the noble gas before the element you’re trying to find the notation for. In this case, the noble gas before Calcium is Argon. You put the symbol for Argon in square brackets, and then you write out the rest of the notation as you would normally.
This would look like [Ar]4s^2
The 4s^2 is because Calcium is the second element in the 4s columns (refer to the diagram)
Hope this helps :)
It's called frequency, its usually stated Hertz
Answer:
There are 2 moles of oxygen molecules; there are 4 moles of oxygen atoms.
Explanation:
There will be increase in solubility.
What means solubility in water?
- Water solubility is a measure of the amount of chemical substance that can dissolve in water at a specific temperature.
- The unit of solubility is generally in mg/L (milligrams per liter) or ppm (parts per million).
- Sugar cubes added to a cup of tea or coffee are a common example of a solution.
- The property which helps sugar molecules to dissolve is known as solubility.
- Hence, the term solubility can be defined as a property of a substance (solute) to dissolve in a given solvent.
In case of CuS, S²⁻ will combine with [H⁺] ions to form a precipitate of H₂S .
Hence, there will be increase in solubility.
Learn more about solubility
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