Answer:
E
Explanation:
100 minutes is 5 half lives ( 100 min/20 min/half life)
= (1/2 )^5
1 x 10^20 * (1/2)^5 = 3.125 x10^18 molecules
Answer:
Number of moles = 2 mol
Explanation:
Given data:
Mass of carbon = 24 g
Number of moles = ?
Solution:
Formula:
Number of moles = mass/ molar mass
Molar mass of carbon is 12 g/mol.
Now we will put the values in formula.
Number of moles = 24 g/ 12 g/mol
Number of moles = 2 mol
0.25 moles of CO2 is present in 11 grams of CO2.
Explanation:
A mole represents the number of chemical entities in an element or molecule.
Number of moles of an element or molecule is determined by the formula:
The Number of moles (n) = weight of the atom given ÷ atomic or molecular weight of the one mole of the element or molecule.
Themolar mass of one mole of carbon dioxide is:
12+ ( 16×2)
= 44 gram/mole
The given weight is 44 grams of carbon dioxide.
Putting the values in the equation,
n= 11 gms÷44 gms/ mole
n = 0.25 mole
First, we need the balanced equation: H₂ + Cl₂ ---> 2HCl
since not much information is given, I am assuming we are at STP and that 22.4 Liters= 1 mol
1) let's convert the volume to moles using the molar volume of a gas. also we need to convert the cm₃ to mL, then to Liters.
8 cm³ (1 ml/ 1 cm³)(1 L/ 1000 mL) (1 mol/ 22.4 Liters)= 3.6x10⁻⁴ moles of H₂
2) let's use the mole ratio of the balanced equation to convert moles of H₂ to moles of HCl
3.6x10⁻⁴ mol H₂ (2 mol HCl/ 1 mol H₂)= 7.1x10⁻⁴ mol HCl
3) lastly, we convert the moles of HCl to grams using the molar mass.
molar mass of HCl= 1.01 + 35.5= 36.51 g/mol
7.1x10⁻⁴ mol HCl (36.51 g/mol)=<span> 0.026 grams HCl</span>
when the thermal energy is the energy contained within a system that is responsible for its temperature.
and when the thermal energy is can be determined by this formula:
q = M * C *ΔT
when q is the thermal energy
and M is the mass of water = 100 g
and C is the specific heat capacity of water = 4.18 joules/gram.°C
and T is the difference in Temperature = 50 °C
So by substitution:
∴ q = 100 g * 4.18 J/g.°C * 50
= 20900 J = 20.9 KJ
