Answer:
The answer to your question is: 2.20 x 10 ²³ molecules
Explanation:
Data
mass = 45.7 g
molecules of CF₂Cl₂ = ?
Process
1.- Calculate the mass number of CF₂Cl₂
C = 12 F =2 x 19 Cl = 2 x 35.5
total = 12 + 38 + 71
total = 121 g
2.- Use the Avogradro's number to solve the problem
121 g ------------------- 6.023 x 10²³ molecules of CF₂Cl₂
45.7 g --------------- x
x = (45.7 x 6.023 x 10²³) / 121
x = 2.75 x 10²⁵ / 121
x = 2.20 x 10 ²³ molecules
Answer:
2Fe + O₂ -------------------> 2FeO
8 mol Fe produce
8 mol Fe * 2 mol FeO / 2 mol Fe = 8 mol FeO
Mass of FeO = 8 mol FeO * 71.85 g/mol = 574.8 grams FeO
Explanation:
Having 8 mol of Iron means 8 moles of iron oxide can be produced. Each mole of iron oxide has a molecular weight of 71.85 grams. Therefore, 8 moles of iron oxide should weight 574.8 grams.
+2
Barium has a positive charge of 2
Answer:
3.91 minutes
Explanation:
Given that:
Biacetyl breakdown with a half life of 9.0 min after undergoing first-order reaction;
As we known that the half-life for first order is:

where;
k = constant
The formula can be re-written as:



Let the initial amount of butter flavor in the food be
= 100%
Also, the amount of butter flavor retained at 200°C
= 74%
The rate constant 
To determine how long can the food be heated at this temperature and retain 74% of its buttery flavor; we use the formula:


Substituting our values; we have:

t = 3.91 minutes
∵ The time needed for the food to be heated at this temperature and retain 74% of its buttery flavor is 3.91 minutes