Answer: In the possible source of error goes: Changing two variables at once to increase rate of data collection, Taking turns with lab partners performing different tasks in an experiment, Measuring millimeters with an ordinary meter stick
In the good experimental practice goes: Measuring in standard metric units, Doing repetitive trials of the same experiment, changing the angle of a ramp in an experiment by constant intervals
Explanation: hopefully this helps i got them right so it guaaranteed you will get this right aswell.
Answer:
No
Explanation:
One mole of P₄ react with six moles of I₂ and gives 4 moles of PI₃.
When one gram phosphorus and 6 gram of iodine react they gives 8.234 g
ram of PI₃ .
Given data:
Mass of phosphorus = 1 g
Mass of iodine = 6 g
Mass of PI₃ = ?
Solution:
Chemical equation:
P₄ + 6I₂ → 4PI₃
Number of moles of P₄:
Number of moles = Mass /molar mass
Number of mole = 1 g / 123.9 g/mol
Number of moles = 0.01 mol
Number of moles of I₂:
Number of moles = Mass /molar mass
Number of moles = 6 g / 253.8 g/mol
Number of moles = 0.024 mol
Now we will compare the moles of PI₃ with I₂ and P₄.
I₂ : PI₃
6 : 4
0.024 :
4/6×0.024 = 0.02
P₄ : PI₃
1 : 4
0.01 : 4 × 0.01 = 0.04 mol
The number of moles of PI₃ produced by I₂ are less it will be limiting reactant.
Mass of PI₃ = moles × molar mass
Mass of PI₃ = 0.02 mol × 411.7 g/mol
Mass of PI₃ = 8.234 g
Answer:
Element Helium have<u> 2 energy levels. </u>
Explanation:
<u>HELIUM -</u> With the symbol He and the atomic number 2, helium is a chemical element. It is a colorless , odorless, tasteless, non-toxic, inert, monatomic gas that is the first in the periodic table in the noble gas group. Of all the elements, its boiling point is the lowest.
At about 24 % of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined, it is present. In both the Sun and Jupiter, its abundance is identical to this. This is due to helium-4's very high nuclear binding energy (per nucleon) with respect to the next three elements following helium.
<u>Hence , the answer is 2 energy levels in Helium atom.</u>
Answer:
Explanation:
Use the gas equation: PV=nRT
P=pressure
V=Volume
R= gas constant of around 8.31 J/K/mol
T=temperature
n= number of moles
To find n, Rearrange:
n=PV/RT
102kPa= 102,000 kilo pascals which standard form is 102 x 10^3
Convert Celsius to kelvin, which you just add 273.15. So:
37+273.15=310.15 K round to a whole number is 310 K
Sub in all numbers to calculate the mol
n= 102 x 10^3 x 2.20 x 10^3/ 8.31 x 310 (cross out 10^3 as this will make a big number)
n=102 x 2.2/8.31 x 310 =0.087 mol
We know 1 g=29 moles
Multiply 29 moles with 0.087 to find the grams
29*0.087=2.523, which to one d.p is 2.5 g
Hence, the child's lung will hold 2.5 g of air.
Hope this helps you :)
Have a nice day!!
