Answer:
•How do you find the delta H per grams in an chemical formula
➢ Subtract the sum of the heats of formation of the reactants from that of the products to determine <u>delta H: delta H = –110.53 kJ/mol</u> – (–285.83 kJ/mol) = 175.3 kJ.
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The answer is 20 because in an atom no of protons equal no of electrons
Answer: - 986.6 kj/mol
Explanation:
1) Equation given:
CaO(s) + H₂O (l) → Ca (OH)₂ (s) δh⁰ = −65.2 kj/mol
2) Standard enthalpies of formation given:
CaO, δhf⁰ = −635.6 kj/mol
H₂O, δhf⁰ = −285.8 kj/mol
3) Calculate the standard enthalpy of formation of Ca(OH)₂.
δh⁰ = ∑δh⁰f of products - ∑ δh⁰f of reactants
Using the mole coefficients of the balanced chemical equation:
δh⁰ = δh⁰f Ca(OH)₂ - δh⁰f CaO - δh⁰f H₂O
⇒ δh⁰f Ca(OH)₂ = δh⁰ + δh⁰f CaO + δh⁰f H₂O
⇒ δh⁰f Ca(OH)₂ = - 65.2 kj/mol − 635.6 kj/mol) − 285.8 kj/mol) = - 986.6 kj/mol.
<h3>
Answer:</h3>
1.926 g of NaOH
<h3>
Explanation:</h3>
Concept tested: Mole and Avogadro's number
- We need to know that , 1 mole of a compound contains number of molecules equivalent to the Avogadro's number.
- Th Avogadro's number is 6.022 × 10^23
Therefore;
- 1 mole of a compound = 6.022 × 10^23 molecules
In this case; Our compound is NaOH
Therefore;
1 mole of NaOH contains 6.022 × 10^23 molecules
But; Molar mass of NaOH is 40.0 g/mol
Therefore;
- 40.0 g of NaOH contains 6.022 × 10^23 molecules
With this we can calculate the mass of 2.90 × 10^22 molecules
- Mass of a compound = (number of molecules ÷ Avogadro's constant) × molar mass
Therefore;
Mass of NaOH =(2.90 × 10^22 molecules ÷ 6.022 × 10^23 molecules)40g
= 1.9263 g
= 1.926 g NaOH
Thus, the mass of NaOH is 1.926 g
The molar absorptivity is
Molar absorptivity is defined as the measure a compound's ability to absorb light of a specific wavelength. It is represented by the constant/symbol 'ε'.
The molar absorptivity is given by :
A = εcl
where A is the absorbance
ε is the molar absorptivity
c is the molar concentration of the compound
and l is the path length
here, the molar concentration of the solution is 0.16 mol
and the path length is 1 cm
to find the molar absorptivity , one must know the absorbance of the material.
(To know more about Molar absorptivity : brainly.com/question/18130658)
