Silicon, which occurs in nature as sio2, is the material from which most computer chips are made. if sio2 is heated until it melts into a liquid, it reacts with solid carbon to form liquid silicon and carbon monoxide gas. in an industrial preparation of silicon, 63.8 kg of sio2 reacted with 25.8 kg of carbon to produce 22.4 kg of silicon.

a. determine limiting reactant
b. determine theoretical yield
c. determine % yield

The limiting reactant is SiO2

The theoretical yield is 29.82 Kg

The % yield is 75.1 %

Explanation:

Step 1: Data given

Mass of SiO2 = 63.8 Kg

Mass of carbon = 25.8 Kg

Actual yield of silicon = 22.4 Kg

Molar mass of SiO2 = 60.085 g/mol

Molar mass of Carbon = 12g/mol

Molar mass of Si = 28.085 g/mol

Step 2: the balanced equation

SiO2 + 2C → Si + 2CO

This means for 1 mole of SiO2 consumed, we need 2 moles of Carbon to produce 1 mole of Silicon and 2 moles of CO

Step 3: Calculate moles of SiO2

Number of moles = mass of SiO2 / Molar mass of SiO2

Number of moles SiO2 = 638000 grams / 60.085 g/mol

Number of moles SiO2 = 1061.8 moles

Step 4: Calculate moles of Carbon

Number of moles = mass of C / Molar mass of C

Number of moles C = 258000 grams / 12 g/mol

Number of moles C = 2150 moles

Step 5: Calculate limiting reactant

SiO2 is the limiting reactant. It will completely react ( 1061.8 moles). Carbon is in excess. There will react 2*1061.8 = 2123.6 moles. There will remain 26.4 moles of Carbon.

Step 6: Calculate moles of Si produced

For 1 mole of SiO2 consumed, we need 2 moles of Carbon to produce 1 mole of Silicon

If there reacts 1061.8 moles of SiO2, there will be produced 1061.8 moles of Si

Step 7: Calculate mass of Si

Mass = numbers of moles Si* Molar mass Si

Mass = 1061.8 moles * 28.085 g/mol

mass = 29820.65 grams = 29.82 Kg

The theoretical yield is 29.82 Kg of silicon

Step 8: Calculate the percent yield

% yield = actual yield / theoretical yield = 22.4 kg /29.82 Kg * 100 % = 75.1 %

The % yield is 75.1 %

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.