Answer:
They all have the same fundamental properties of reflection
The volume of 0.20 moles of helium at STP is 4.5 liters.
Explanation:
Given:
Number of moles = 0.20 moles
To Find:
The volume of Helium at STP =?
Solution:
According to ideal gas law
PV = nRT
where
P is pressure,
V is volume,
n is the number of moles
R is the gas constant, and
T is temperature in Kelvin.
The question already gives us the values for p and T
,because helium is at STP. This means that temperature is 273.15 K and pressure is 1 atm
.
We also already know the gas constant. In our case, we'll use the value of
0.08206 L atm/K mol since these units fit the units of our given values the best
On substituting these values we get
V = 4.5 Liters
Answer: It is important for an equation to be balanced because if it is not then the reactants won't match the products.
Explanation: I don't know if you will understand this but here:
Let's say you're cooking eggs, you're reactants so to speak would be 3 eggs and 1 tablespoon of oil so you put it together using heat and a pan. Your products have to match what you have in the beginning. You cannot have an equation that looks like this
Reactants = 3eggs + 1Tbsp oil ---pan/heat---> 6eggs + 1 cup of oil
You cannot get something from what you don't have. The number of how much of an element you have must be the same of both sides of the equation.
1) Chemical reaction:
Fe2O3 + 2Al ---> Al2O3 + 2Fe
2) molar ratios
1 mol Fe2O3 : 2Al : 1 mol Al2O3 : 2 mol Fe
3) Convert 15.0 g of iron into moles
atomic mass Fe = 55.8 g/mol
moles = mass in grams / atomic mass = 15.0 g / 55.8 g/mol = 0.269 mol
4) Use proportions to determine the moles of Fe2O3, Al, and Al2O3
a) 1mol Fe2O3 / 2 mol Fe = x / 0.269 mol Fe
x =
=> x = 0.269 mol Fe * 1 mol Fe2O3 / 2 mol Fe = 0.134 mol Fe2O3
b) 2 mol Al / 2 mol Fe = x / 0.269 mol Fe
=> x = 0.269 mol Al
c) 2 mol Fe / 1 mol Al2O3 = 0.269 mol Fe / x
=> x = 0.269 mol Fe * 1 mol Al2O3 / 2 mol Fe
x = 0.134 mol Al2O3
5) Convert moles to grams
a) Fe2O3
molar mass Fe2O3 = 2* 55.8 g/mol + 3*16g/mol = 159.6 g/mol
mass = molar mass * number of moles
mass = 159.6 g/mol * 0.134 mol = 21.4 g
b) Al
atomic mass = 27.0 g/mol
mass = number of moles * atomic mass = 0.269 mol * 27.0 g/mol = 7.26 g
c) Al2O3
molar mass = 2 * 27.0 g/mol + 3*16.0 g/mol = 102.0g/mol
mass Al2O3 = numer of moles * molar mass = 0.134 mol * 102.0 g/mol = 13.7 g
Answers:
21.4 g Fe2O3
7.26 g Al
13.7 g Al2O3
