Answer:
Average of measurements = 20.97 cm
Explanation:
Given data:
Three measurements of pete's = 20.9 cm, 21.0 cm, 21.0 cm.
Average value of measurements = ?
Formula:
Average of measurements = sum of all measurements / Total number of measurements
Solution:
Average of measurements = 20.9 cm + 21.0 cm + 21.0 cm. / 3
Average of measurements = 62.9 cm / 3
Average of measurements = 20.97 cm
88.98 %
The Balance Chemical Equation is as follow,
2 HCl + Pb(NO₃)₂ → 2 HNO₃ + PbCl₂
According to equation,
331.2 g (1 mole) Pb(NO₃)₂ produces = 278.1 g (1 mole) PbCl₂
So,
870 g of Pb(NO₃)₂ will produce = X g of PbCl₂
Solving for X,
X = (870 g × 278.1 g) ÷ 331.2 g
X = 730.5 g of PbCl₂
Therefore,
Theoretical Yield = 730.5 g
Also as given,
Actual Yield = 650 g
So using following formula for percentage yield,
%age Yield = (Actual Yield / Theoretical Yield) × 100
Putting values,
%age Yield = (650 g / 730.5 g) × 100
%age Yield = 88.98 %
Brianliest please and thank you.
Answer:
~1.417M
Explanation:
Molarity=(number of moles of solute)/(litres of solution)
In this case, we need to find moles of potassium bromide.
Mass=25.3g
Molar mass= 119g/mol
moles=(mass/molar mass)
=(25.3)/(119)
=0.2126moles of potassium bromide
Molarity=(0.2126)/(150/1000)
~1.417M
Hope this helps:)
Answer:
The first 50 elements along with their valences are given below :
1. Hydrogen = 1
2. Helium = 0
3. Lithium = 1
4. Beryllium = 2
5. Boron = 3
6. Carbon = 4
7. Nitrogen = 3
8. Oxygen = 2
9. Fluorine = 1
10. Neon = 0
11. Sodium = 1
12. Magnesium = 2
13. Aluminium = 3
14. Silicon = 4
15. Phosphorus = 3
16. Sulphur = 2
17. Chlorine = 1
18. Argon = 0
19. Potassium = 1
20. Calcium = 2
21. Scandiun = 3
22. Titanium = 3
23. Vanadium = 4
24. Chromium = 3
25. Manganese = 4
26. Iron = 2
27. Cobalt = 2
28. Nickel = 2
29. Copper = 2
30. Zinc = 2
31. Gallium = 3
32. Germanium = 4
33. Arsenic = 3
34. Selenium = 2
35. Bromine = 1
36. Krypton = 0
37. Rubidium = 1
38. Strontium = 2
39. Yttrium = 3
40. Zirconium = 4
41. Niobium = 3
42. Molybdenum = 3
43. Technetium = 7
44. Ruthenium = 4
45. Rhodium = 3
46. Palladium = 4
47. Sliver = 1
48. Cadmium = 2
49. Indium = 3
50. Tin = 4
<u>Note</u> :
An element like Iron, copper can have more than one valencies.
