Answer:
double replacement
Explanation:
The reaction equation is given as:
Pb(NO₃)₂ + 2KI → PbI₂ + KNO₃
This reaction is a double displacement reaction.
In this form of reaction, there is an actual exchange of partners to form new compounds.
AB + CD → AD + CD
One of the following condition serves as driving force for the reaction:
- formation of an insoluble compound
- formation of water or any other non-ionizing compound
- liberation of a gaseous product.
Answer:
1. How many ATOMS of boron are present in 2.20 moles of boron trifluoride? atoms of boron.
2. How many MOLES of fluorine are present in of boron trifluoride? moles of fluorine.
Explanation:
The molecular formula of boron trifluoride is
.
So, one mole of boron trifluoride has one mole of boron atoms.
1. The number of boron atoms in 2.20 moles of boron trifluoride is 2.20 moles.
The number of atoms in 2.20 moles of boron is:
One mole of boron has ----
atoms.
Then, 2.20 moles of boron has
-
2. Calculate the number of moles of BF3 in 5.35*1022 molecules.

One mole of boron trifluoride has three moles of fluorine atoms.
Hence, 0.0888moles of BF3 has 3x0.0888mol of fluorine atoms.
=0.266mol of fluorine atoms.
Answer:
1.35 × 10⁴ kg/m³ at 22 °C; 1.34 × 10⁴ kg/m³ at 100 °C
Explanation:
The cubic expansivity (γ) of a liquid is the fractional change in volume per unit change in temperature.
Multiply by V₀ΔT and transpose
ΔV = γV₀ΔT
and
V = V₀ + ΔV
===============
<em>At 0 °C
</em>
Assume you have 1 m³ of Hg
ρ = m/V Multiply by V and transpose
m = ρV
ρ = 1.36 × 10⁴ kg/m³
m = 1.36 × 10⁴ × 1 = 1.36 × 10⁴ kg
===============
<em>At 22 °C
</em>
Assume that you have 1 m³ of Hg
γ = 180 × 10⁻⁶ K⁻¹
ΔT = 22 °C – 0 °C = 22 °C
ΔV = 180 × 10⁻⁶ × 22
ΔV = 3.96 × 10⁻³ m³ Calculate volume
V = 1 + 0.00396
V = 1.00396 m³ Calculate density
ρ = 1.36 × 10⁴/1.00396
ρ = 1.35 × 10⁴ kg/m³
===============
<em>At 100 °C
</em>
ΔT = 100 °C – 0 °C = 100 °C
ΔV = 180 × 10⁻⁶ × 100
ΔV = 0.0180 m³ Calculate volume
V = 1 + 0.0180
V = 1.0180 m³ Calculate density
ρ = 1.36 × 10⁴/1.0180
ρ = 1.34 × 10⁴ kg/m³
Remark
The balance numbers in front of the chemicals tell you how to set up the proportion to solve your question
For every 2 moles Na only 1 mole of Cl2 is required.
Equation
2 moles Na:1 mole Cl2 :: x moles Na:4 moles Cl2
Solution
2/1 = x/4 Cross multiply
2*4 = x*1
8 = x
Conclusion
8 moles of Na will be used. <<< Answer