<em>i think the answer is b </em>
Answer:
Physical changes are changes that do not alter the identity of a substance. Chemical changes are changes that occur when one substance is turned into another substance.
Explanation:
D = m / V
It even gives you the density of gold in the problem. Major hint. Once you know the volume (using V = m / D) then you can calculate the height (thickness) from the equation...
V = L x W x H
Volume = Length x Width x Height
start by converting 200.0 mg into grams
1000 mg = 1 g
200. mg x (1 g / 10^3 mg) = 0.200 g
V = m / D
V = 0.200 g / (19.32 g/cm^3)
V = 0.01035 cm^3
Convert 2.4 ft and 1 ft to cm
2.4 ft x (12 in / 1 ft) x (2.54 cm / 1 in) = 73.15 cm
1 ft = 30.48 cm
Compute the height (thickness)
V = LxWxH
H = V / LW = 0.01035 cm^3 / 73.15 cm / 30.48 cm
H = 4.64 x 10^-6 cm
Convert to nanometers
4.64 x 10^-6 cm x (1 m / 100 cm) x (10^9 nm / 1 m) = 46.4 nm
Knowing the atomic radius of gold, I might have asked my students for the minimum number of gold atoms in this thickness of gold. This would assume that the gold atoms are all in a row. This would give the minimum number of gold atoms.
Atomic radius gold = 174 pm
Diameter = 348 pm
46.4 nm x (1 m / 10^9 nm) x (10^12 pm / 1 m) x (1 Au atom / 248 pm) = 133 atoms of gold
The PH of water is 7 because it contains an equal amount of h and oh- ions.
The mass of Ce(NO3)₄ that will be needed to create the solution was 24.16 g (in grams).
<h3>
What exactly is the solution?</h3>
A homogenous mixture with one or even more solutes that have been dissolved in the solvent is known as a solution. The material that a solute dissolves in to create a homogenous mixture is known as a solvent. To create a homogenous mixture, a component must dissolve in a solvent.
<h3>
What is an illustration of a solution?</h3>
One nanometer or smaller particles are referred to as a solution in a homogeneous mixture made up of two or more components. There are many different types of solutions, including sugar and salt solutions and fizzy water. Each component shows up as a different phase in a solution.
<h3>
Briefing:</h3>
Mole of Ce(NO₃)₄ = 0.06225 mole
Molar of Ce(NO₃)₄ = 140.12 + 4[14 + (16×3)]
= 140.12 + 4[14 + 48]
= 140.12 + 4[62]
= 140.12 + 248
= 388.12 g/mol
Mass of Ce(NO₃)₄ = 0.06225 × 388.12
Mass of Ce(NO₃)₄ = 24.16 g
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