M = Sr (strontium)
<em>Step 1.</em> Calculate the <em>moles of CO_2</em>.
Moles of CO_2 = 0.395 g CO_2 × (1 mol CO_2/44.01 g CO_2)
= 0.008 975 mol CO_2
<em>Step 2</em>. Calculate the <em>moles of MCO_3</em>.
Moles of MCO_3 = 0.008 975 mol CO_2 × (1 mol MCO_3/1 mol CO_2)
= 0.008 975 mol MCO_3
<em>Step 3</em>. Calculate the molar mass of <em>MCO_3</em>
MM = grams/moles = 1.324 g/0.008 75 mol = 147.5 g/mol
<em>Step 4</em>. Calculate the <em>atomic mass of M</em>
M_r = <em>x</em> + 12.01 + 3×16.00 = <em>x</em> + 60.01 = 147.5
<em>x</em> = 147.5 – 60.01 = 87.5
<em>Step 5. Identify M</em>.
The element with the closest atomic mass is Sr (A_r = 87.6).
∴ M = Sr and the compound is SrCO_3.
Answer:
C + O2 ⇒ CO2
mole of O2: 18.6/32=0.58125= mole of CO2
⇒ gram of CO2: 0.58125*(12+32)=25.575
Explanation:
<span>Avogadro's number
represents the number of units in one mole of any substance. This has the value
of 6.022 x 10^23 units / mole. This number can be used to convert the number of
atoms or molecules into number of moles.
45.6 g Au ( 1 mol / 196.97 g ) ( </span>6.022 x 10^23 atoms / mole ) = 1.39x10^23 atoms Au
1) Chemical equation
16Fe(s) + 3S8(s) ---> 8Fe2S3
2) Molar ratios:
16 mol Fe : 3 mole S8 : 8 mol Fe2S3
3) Convert masses in grams to number of moles
number of moles = mass in grams / molar mass
a) iron, Fe
mass = 3.0 g
atomic mass = 55.845 g/mol
=> number of moles of Fe = 3.0g / 55.845 g/mol = 0.0537 mol
b) Sulfur, S8
mass = 2.5 g
molar mass = 8*32.065 g/mol = 256.52 g/mol
=> number of moles of S8 = 2.5g / 256.52 g/mol = 0.009746 mol
4) Limiting reactant
Theoretical ratio actual ratio
16 mol Fe / 3 mol S8 0.0537 mol Fe / 0.009746 mol S8
5.33 5.50
So, there is a little bit more Fe than the theoretical needed to react all the S8, which means the S8 is the limiting reactant.
5) Calculate the number of moles of iron (III) produced with 2.5 g (0.009746 moles) of S8
3moles S8 / 8 moles Fe2S3 = 0.009746 moles S8 / x
=> x = 0.009746 * 8 / 3 moles Fe2S3 = 0.026 moles Fe2S3
6) Convert 0.026 moles Fe2S3 into grams
mass in grams = number of moles * molar mass
molar mass of Fe2S3 = 207.9 g/mol
mass = 0.026 mol * 207.9 g/mol = 5.40 g
7) Answer: option D)