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3 years ago

How many atoms are centered on the (100) plane for the fcc crystal structure?

Chemistry

1 answer:

Setler [38]3 years ago

5 0

Here, we have to get the number of atoms present in the 100 plane of the FCC crystal lattice.

There will be 2 atoms in 100 plane of FCC crystal lattice.

In the face centered crystal (FCC) lattice there are atoms at each corner of the cube and each are shared by 4 another atoms. And an atom is present at the face of the crystal.

For the 100 plane of the Miller indices the intercepts are a, ∞, ∞ or 2a, ∞, ∞.

Thus, for the 4 atoms of the corner at the cube shared by 4 other atoms will contribute, 4 × $\frac{1}{4}$ = 1 and the un-shared atoms at the face will contribute another 1, which make the total atom 1 + 1 = 2.

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A 125g metal block at a temperature of 93.2 degrees Celsius was immersed in 100g of water at 18.3 degrees Celsius. Given the spe

nikitadnepr [17]

Answer:

$\large \boxed{34.2\, ^{\circ}\text{C}}$

Explanation:

There are two heat transfers involved: the heat lost by the metal block and the heat gained by the water.

According to the Law of Conservation of Energy, energy can neither be destroyed nor created, so the sum of these terms must be zero.

Let the metal be Component 1 and the water be Component 2.

Data:

For the metal:

$m_{1} =\text{125 g; }T_{i} = 93.2 ^{\circ}\text{C; }\\C_{1} = 0.900 \text{ J$^{\circ}$C$^{-1}$g$^{-1}$}$

For the water:

$m_{2} =\text{100 g; }T_{i} = 18.3 ^{\circ}\text{C; }\\C_{2} = 4.184 \text{ J$^{\circ}$C$^{-1}$g$^{-1}$}$

$\begin{array}{rcl}\text{Heat lost by metal + heat gained by water} & = & 0\\q_{1} + q_{2} & = & 0\\m_{1}C_{1}\Delta T_{1} + m_{2}C_{2}\Delta T_{2} & = & 0\\\text{125 g}\times 0.900 \text{ J$^{\circ}$C$^{-1}$g$^{-1}$} \times\Delta T_{1} + \text{100 g} \times 4.184 \text{ J$^{\circ}$C$^{-1}$g$^{-1}$}\Delta \times T_{2} & = & 0\\112.5\Delta T_{1} + 418.4\Delta T_{2} & = & 0\\112.5\Delta T_{1} & = & -418.4\Delta T_{2}\\\Delta T_{1} & = & -3.719\Delta T_{2}\\\end{array}$

$\Delta T_{1} = T_{\text{f}} - 93.2 ^{\circ}\text{C}\\\Delta T_{2} = T_{\text{f}} - 18.3 ^{\circ}\text{C}$

$\begin{array}{rcl}\Delta T_{1} & = & -3.719\Delta T_{2}\\T_{\text{f}} - 93.2 ^{\circ}\text{C} & = & -3.719 (T_{\text{f}} - 18.3 ^{\circ}\text{C})\\T_{\text{f}} - 93.2 ^{\circ}\text{C} & = & -3.719T_{\text{f}} + 68.06 ^{\circ}\text{C}\\4.719T_{\text{f}} & = & 161.3 ^{\circ}\text{C}\\T_{\text{f}} & = & \mathbf{34.2 ^{\circ}}\textbf{C}\\\end{array}\\\text{The final temperature of the block and the water is $\large \boxed{\mathbf{34.2\, ^{\circ}}\textbf{C}}$}$

3 0

3 years ago

In the compound cah2 calcium has an oxidation number of 2+ and hydrogen has an oxidation number of

sesenic [268]

The oxidation number of H is -1.

Sum of the oxidation numbers in each element = charge of the complex

CaH₂ has 1 Ca atom and 2H atoms. The charge of the complex is zero. Let’s say Oxidation number of H is "a".

Then,

(+2) + 2 x a = 0

+2 + 2a = 0

2a = -2

a = -1

Hence, the oxidation number of Hydrogen atom in CaH₂ is -1

7 0

3 years ago

I'd: 9872093250, password: qqqqq, join the meeting

Sonja [21]

You keep on saying join fast wdym?!

4 0

3 years ago

How to tell the difference between polar and nonpolar covalent bonds?

NemiM [27]

You need to look at the electronegativity and decide wheter the difference of both of the numbers are significant enough to form a polar bond

3 0

3 years ago

How does the energy of the activated complex compare with the energies of reactants and products? select one:

Free_Kalibri [48]

Answer:

Option d. it is higher than the energy of both reactants and products

Explanation:

Activated complex, also known as transition state, is the intermediate structure formed in the course of a chemical reaction.

The activated complex is very unstable and of short life: it is at the peak of the potential chemical diagram, and can transform either into the reactants (backward) or the products (forward).

The activation energy of the reaction is the energy needed to reach the activated complex, then both reactants and products are lower in potential chemical energy than the activated complex, which is what explains why the activated complex can transform into one or another, reactants or products.

5 0

3 years ago