The whitening toothpastes showed differences in their physical-chemical properties. All toothpastes promoted changes to the surface, probably by the use of a bleaching agent.
Answer:
Percent yield = 57.8 %
Theoretical yield = 11.781 g
Explanation:
Given data:
Mass of CaO produced = 6.81 g
Mass of CaCO₃ react = 20.7 g
Theoretical yield = ?
Percent yield = ?
Solution:
Chemical equation:
CaCO₃ → CaO + CO₂
Number of moles of CaCO₃ :
Number of moles = mass/molar mass
Number of moles = 20.7 g/ 100.1 g/mol
Number of moles = 0.21 mol
Now we will compare the moles of CaCO₃ with CaO.
CaCO₃ : CaO
1 : 1
0.21 : 0.21
Theoretical yield of CaO:
Mass = number of moles × molar mass
Mass = 0.21 mol × 56.1 g/mol
Mass = 11.781 g
Percent yield:
Percent yield = ( actual yield / theoretical yield ) × 100
Percent yield = (6.81 g/ 11.781 g) × 100
Percent yield = 57.8 %
Answer:
3rd one
Explanation:
I just took the test and got 100%
Answer : The pH of the resulting solution is 4.6
Explanation : Given,
Activity coefficient for acetic acid = 1.000
Activity coefficient for acetate ion = 0.775
Ionic strength = 0.10 M
To calculate the pH of resulting solution we are using Henderson Hesselbach equation :
![pH=pK_a+\log \frac{[Salt]}{[Acid]}](https://tex.z-dn.net/?f=pH%3DpK_a%2B%5Clog%20%5Cfrac%7B%5BSalt%5D%7D%7B%5BAcid%5D%7D)
Now put all the given values in this expression, we get:
Thus, the pH of the resulting solution is 4.6
Answer:
1072 torr
Explanation:
To answer this problem we can use <em>Gay-Lussac's law</em>, which states:
Now we convert the given temperatures into K:
- T₁ = 15°C ⇒ 15+273.16 = 288.16 K
- T₂ = 36°C ⇒ 36+273.16 = 309.16 K
We <u>input the data</u>:
- 1000 torr * 309.16 K = P₂ * 288.16 K
And <u>solve for P₂</u>:
