Question

1. find the reactants mass in grams using the following reaction.

iron metal reacts in moist air causing oxidation and forms iron oxide. this does not protect the iron surface so further reaction continues to occur, and flakes off causing more iron metal to oxidize. this process is called rusting. using the following reaction find the mass of iron before it reacts with oxygen.
____grams of iron + 96 grams of oxygen → 316 grams of iron oxide
20.) methane (ch4) reacts with oxygen (o2) and forms carbon dioxide (co2) and water (h2o). which equation below accurately represents this equation?
a. ch4 + 2o2 → co2 + h2o
b. 2ch4 + o2 → 2co2 + h2o
c. ch4 + 2o2 → co2 + 2h2o
d. 2ch4 + 2o2 → co2 + 2h2o
21.) which equation below accurately represents the formation of magensium oxide?
a. mg + 2o2 → 2mgo
b. mg + o2 → 2mgo
c. 2mg + o2 → mgo
d. 2mg + o2 → 2mgo
22.) propane reacts with oxygen to form carbon dioxide and water, which equation below accurately represents this reaction.?
a. 2c3h8 + 5o2 → c3o2 + 4h2o
b. c3h8 + 5o2 → 3co2 + 4h2o
c. 2c3h8 + 7o2 → 4co2 + 3h2o
d. c3h8 + 7o2 → 4co2 + 3h2o

Explanation:

19.

Step1: Apply law of conservation of mass

According to the law of conservation of mass, the total mass of reactants equals the total mass of products. Let the mass of iron be $x$ grams. The equation is $x + 96=316$.

Step2: Solve for $x$

Subtract 96 from both sides of the equation: $x=316 - 96$.

Balance the chemical - equation for the combustion of methane. For the reaction of methane ($CH_4$) with oxygen ($O_2$) to form carbon dioxide ($CO_2$) and water ($H_2O$), we need to ensure that the number of each type of atom is the same on both sides of the equation.
$CH_4+2O_2
ightarrow CO_2 + 2H_2O$ has 1 carbon atom, 4 hydrogen atoms, and 4 oxygen atoms on both sides.

Balance the equation for the formation of magnesium oxide. Magnesium ($Mg$) reacts with oxygen ($O_2$) to form magnesium oxide ($MgO$). We need 2 moles of magnesium to react with 1 mole of oxygen to form 2 moles of magnesium oxide to balance the atoms.
$2Mg+O_2
ightarrow 2MgO$ has 2 magnesium atoms and 2 oxygen atoms on both sides.

Answer:

220

20.