Answer:
a) 31 g
b) 0.867, 0.132
c) 86.75%, 13.24%
Explanation:
Given:
Mass of the sample of galena = 234 g
Mass of the lead in the sample = 203 g
Now,
galena = sulfur + lead
thus,
a) Mass of the sulfur will be calculated as:
= mass of the sample of galena - mass of lead
on substituting the values, we have
= 234 - 203
or
= 31 g
b) Now,
the mass fraction of lead will be calculated as = ( mass of lead) / (total mass of the galena sample)
= 203/234 = 0.867
and,
Mass fraction of sulfur will be = ( mass of the sulfur in the sample) / ( total mass of the sample)
thus we have
= 31/234
⇒ 0.132
(c) Now the mass percentage of lead in the sample = (mass of lead in the sample ) / (total mass of sample) × 100%
= (203 / 234) x 100%
= 86.75%
and
the mass percentage of sulfur in the sample = ( mass of sulfur in the sample ) / (total mass of the sample) × 100%
= (31 / 234) × 100%
⇒ 13.24%
Answer:
Mass of benzene required = 0.78 g
Explanation:
Given data:
Mass of CO₂ produced = 2.66 g
Mass of benzene required = ?
Solution:
Chemical equation:
2C₆H₆ + 15O₂ → 6H₂O + 12CO₂
Number of moles of CO₂:
Number of moles = mass/molar mass
Number of moles = 2.66 g/ 44 g/mol
Number of moles = 0.06 mol
Now we will compare the moles of CO₂ with C₆H₆.
CO₂ : C₆H₆
12 : 2
0.06 : 2/12×0.06=0.01 mol
Mass of benzene required:
Mass = number of moles × molar mass
Mass = 0.01 mol × 78.11 g/mol
Mass = 0.78 g
Q=mc(delta)T
118=0.005×c×15
c=118/(0.005×15)
c= 1573 J/kg/C
The definition of pseudoscience is collection of beliefs or practices mistakenly regarded as being based on scientific method. which B is very similar to that. I believe the answer is A.
Have a nice day.