Answer:
12.8 g
Explanation:
Step 1: Write the balanced neutralization reaction
Al(OH)₃ + 3 HCl ⇒ AlCl₃ + 3 H₂O
Step 2: Calculate the moles corresponding to 17.9 g of HCl
The molar mass of HCl is 36.46 g/mol.
17.9 g × 1 mol/36.46 g = 0.491 mol
Step 3: Calculate the moles of Al(OH)₃ that completely react with 0.491 moles of HCl
The molar ratio of Al(OH)₃ to HCl is 1:3. The reacting moles of Al(OH)₃ are 1/3 × 0.491 mol = 0.164 mol
Step 4: Calculate the mass corresponding to 0.164 moles of Al(OH)₃
The molar mass of Al(OH)₃ is 78.00 g/mol.
0.164 mol × 78.00 g/mol = 12.8 g
Copper oxide reacts with hydrochloric acid to produce copper chloride and water.
So the basic equation that illustrates this reaction is:
CuO + HCl ......> CuCl2 + H2O
Now, we need to balance this equation:
the number of copper and oxygen moles are balanced.
For each of hydrogen and chlorine, we have one mole as a reactant and two moles as product.
Therefore, to balance this, we will add an extra mole of HCl in the reactants.
Based on this, the final balanced equation would be:
CuO + 2HCl ................> CuCl2 + H2O
Answer:
c. Only certain energies are allowed for the electron in a hydrogen atom
Explanation:
Emission spectrum are produced when the excited electron in a atom release the energy in the form of photons to come to ground state. These photons are of different wavelengths depending on the excitation state of emitting electron or transition of electron. These electromagnetic radiation are observed through prism to produce the spectrum.
As the name indicates this spectrum is produced by emission of energy. Although the electron can be excited by different methods such as by heating but the key point is that electrons in hydrogen atom will emit the photons of same energy which they absorb and each electron can absorb only certain type of energy. So four lines were observed in the visible spectrum of hydrogen because only certain energies are observed for hydrogen atom.
I feel like it is important, because it is always nice to learn about
new things and keep your mind open, to expand your knowledge.
I hope this helps ^-^
Answer:
Acids have a high concentration of [H⁺] ions
Explanation:
In order to know about the acids, a solution is acidic when pH < 7
As pH is lower than 7, the pOH > 7
When pH = 7, solution is neutral
When pH is greater than 7, solution is basic
pH = - log [H⁺]
pOH = - log [OH⁻]
Imagine a solution of pure HCl 0.2 M
HCl → H⁺ + OH⁻
[H⁺] = 0.2 M → pH = - log 0.2 → 0.69
pH + pOH = 14
pOH = 14 - 0.69 = 13.31
10^-pOH = [OH⁻] → 10⁻¹³°³¹ = 4.89ₓ10⁻¹⁴
In conclussion [H⁺] > [OH⁻]
