What can you infer about copper's properties?

A hypothetical metal crystallizes with the face-centered cubic unit cell. The radius of the metal atom is 234 picometers and its

AleksAgata [21]

Answer:

$\delta=101.13 g/cm^3$

Explanation:

As can be seen in the Figure in a face-centered cubic unit cell you have:

Six halves of atoms
Eight 1/8 of atom (1 in each corner)

In total:

$n_{atom}=6*0.5+8*\frac{1}{8}=4 atoms$

Now, each side of the cell is 234 picometers (2.34e-8 cm) long

$V_{cell}=L^3=(2.34e^{-8} cm)^3$

$V_{cell}=1.28*10^{-23}cm^3$

Atoms per cm3:

$n=\frac{4 atoms}{1.28*10^{-23}cm^3}$

$n=3.12*10^{23} atoms/cm^3$

Expressing in mass:

$\delta=3.12*10^{23} atoms/cm^3* \frac{1 mol}{6.022*10^{23}}*195.08 g/mol$

$\delta=101.13 g/cm^3$

6 0

3 years ago

The number of molecules of nitrogen, n2, found in 500.0 g of nitrogen gas is?

8_murik_8 [283]

The molar mass of monotonic Nitrogen is 14 g/mol. Since this is diatomic Nitrogen, double that to 28 g/mol.
Next, divide total mass by molar mass, 500 g / 28 g/mol, which gives <span>17.8571 moles. A mole is defined as being 6.022*10^23 molecules, so multiply moles by molecules/mol (Avogadro's number), and we finally end up with something like 1.075 * 10^25, give or take a few billion particles.</span>

5 0

3 years ago

If the rate of a reaction increases by a factor of 64 when the concentration of reactant increases by a factor of 4, what is the

igomit [66]

The reaction is of order three with respect to the reactant.

<h3>Explanation</h3>

The rate of a reaction of order n about a certain reactant is proportion to the concentration of that reactant raised to the n-th power. This is true only if concentrations of any other reactants stay constant in the whole process.

In other words, Rate = constant × [Reactant]ⁿ, Rate ∝ [Reactant]ⁿ. (The symbol "∝" reads "proportional to".)

In this question,

[4 × Reactant]ⁿ ÷ [Reactant]ⁿ = 64.

In other words, 4ⁿ = 64, where n is the order of the reaction with respect to this reactant.

It might take some guesswork to find the value of n. Alternatively, n can be solved directly with a calculator using logarithms. Taking natural log of both sides:

$\ln{4^n} = \ln{64}\\n\; \ln{4} = \ln{64}\\n = \frac{\ln{64}}{\ln{4}} = 3$ .