No I can’t
EXAMPLE took the test k12
Electric
current passes through a filament of an incandescent bulb, thereby increasing
it temperature. When current flows, it contains electrons through the filament
to produce light. Typically, incandescent light bulb consists
of a glass enclosure that contains tungsten filament. The glass enclosure
contains either a vacuum or an inert gas that serves as the filament protection
from evaporating. Incandescent light bulbs contain a stem attached at to its
base to allow the electrical contacts to run through the envelope without gas
or air leaks.
You must burn 1.17 g C to obtain 2.21 L CO₂ at STP.
The balanced chemical equation is
C + O₂ → CO₂.
<em>Step 1</em>. Convert <em>litres of CO₂ to moles of CO₂</em>.
STP is <em>0 °C and 1 bar</em>. At STP the volume of 1 mol of an ideal gas is 22.71 L.
Moles of CO₂ = 2.21 L CO₂ × (1 mol CO₂/22.71 L CO₂) = 0.097 31 mol CO₂
<em>Step 2</em>. Use the molar ratio of C:CO₂ to <em>convert moles of CO₂ to moles of C
</em>
Moles of C = 0.097 31mol CO₂ × (1 mol C/1 mol CO₂) = 0.097 31mol C
<em>Step 3</em>. Use the molar mass of C to <em>calculate the mass of C
</em>
Mass of C = 0.097 31mol C × (12.01 g C/1 mol C) = 1.17 g C
It looks as if you are using the <em>old (pre-1982) definition</em> of STP. That definition gives a value of 1.18 g C.
C: The electron moves to a lower energy level
First step is to calculate the mass of Ag in each compound separately:
From the periodic table:
molar mass of Ag is 107.87 gm
molar mass of Cl is 35.45 gm
molar mass of Br is 79.9 gm
For AgCl, mass % of Ag = [107.87/143.32] x 100 = 75.26%
For AgBr, mass % of Ag = [107.87/187.77] x 100 = 57.45 %
Second step is to calculate the mass % of each compound in the mixture:
Assume mass % of AgCl is y and that of AgBr is (1-y) as the total percentage is 100% or 1
0.6094 = 0.7526 y + 0.5745 (1-y)
y = 0.8716
This means that the mixture is almost 87% AgCl and 13% AgBr
The mass % of chlorine and bromine together is (100%-60.94%) which is 39.06%
mass % of chlorine = (1-0.6094)(0.8716) x 100 = 34.044%
mass % of bromine = 39.04 - 34.044 = 5.056%
