All categories

3 years ago

Describe the properties of metals, non-metals, and metalloids

1 answer:

3 0

Metals are generally shiny, malleable, and hard. Metals are also good conductors of electricity. Examples of metals are Gold, Silver, Iron, Uranium, and Zinc. Non-metals do not conduct heat or electricity very well. Non-metals are typically brittle and are not easily molded into shapes. Example non-metal elements are Hydrogen and Carbon. Metalloids share characteristics of both metals and non-metals and are also called semimetals. Metalloids are typically semi-conductors, which means that they both insulate and conduct electricity. This semi-conducting property makes Metalloids very useful as a computer chip material. Examples of metalloid elements are Silicon and Boron.

You might be interested in

A truck is driving north at 35 miles per hour and passes a car going south at 40 miles per hour. What is the speed of the car fr

inna [77]

Answer:

Explanation:

right...

7 0

2 years ago

Read 2 more answers

Scientists can use spectral analysis of stars to determine which of the following?

RoseWind [281]

I do believe all of these but core elements can be determined by spectroscopy which includes the use of electromagnetic radiation. Both the surface and core temperature can be measured using light. Surface elements can be found because the absorption lines of different elements in the spectra of the star, but I haven't heard anything about using spectral analysis for core elements.

4 0

3 years ago

Read 2 more answers

Why are earbud wires for an mp3 player coated with plastic

saw5 [17]

2) they add the insulation to better the durability or the earbuds

6 0

3 years ago

Read 2 more answers

A single insulated duct flow experiment using air operating at steady-state is performed in a lab. One measurement location (Sta

weqwewe [10]

Answer:

a) -0.0934 kJ/kg. K

b) The direction of flow is from right to left.

Explanation:

A free flow diagram of the horizontal insulated duct is as shown below.

NOW,

Let assume that the direction of flow is from left to right and consider the following relation for the entropy rate balance equation for a control volume as:

$\frac{\sigma_{cv}}{m}= (s_2-s_1) \geq 0 \ \ \ -------> \ \ \ 1$

Now; if the value for this relation is greater than zero; then we conclude that our assumption is correct.

If the value is less than zero; then we conclude that the assumption is wrong.

Then, the flow is said to be in the opposite direction

Formula for the change in specific entropy can be calculated as:

$s_2-s_1 = s^0(T_2) - s^0(T_1)-R \ In ( \frac{P_2}{P-1}) \ \ \ -------> \ \ \ 2$

where;

$s_1, s_2 , s^0(T_2), s^0(T1)$ are specific entropies

R = universal gas constant

$P_1$ = pressure at location 1

$P_2$ = pressure at location 2

We obtain the specific properties of air at temperature at $T_1$ = (67°C + 273)K = 340 K from the table A-22 ( Ideal gas properties of air)

$s^0(T1)$ = 1.8279 kJ/kg.K

We also obtain the specific properties of air at temperature $T_2$ = 22°C + 273) K = 295 K

From the table A- 22

$s^0(T_2)$ = 1.68515 kJ/kg . K

R = $\frac{8.314 kJ}{28.97 kg.K}$

$P_1 =$ 0.95 bar

$P_2 =$ 0.8 bar

Now replacing our values into equation (2) from above; we have;

$s_2-s_1 = s^0(T_2) -s^0(T_1)-R \ In (\frac{P_2}{P_1} )$

$s_2-s_1 = 1.68515 -1.8279-\frac{8.314}{28.97} \ In (\frac{0.8}{0.95} )$

$s_2-s_1 = 1.68515 -1.8279+ 0.0493$

$s_2-s_1 =-0.0934 \ kJ/kg.K$

Equating our result to equation (1)

$s_2-s_1 \geq 0\\-0.0934 \leq 0$

Therefore , our assumption is wrong and the direction of flow is said to be from right to left.

We therefore conclude that the direction of flow is from right to left.

3 0

3 years ago

A step-down transformer has more loops on which coil?

Nesterboy [21]

A step-down transformer has more loops in : A. Primary coil

Primary coil refers to the coil to which alternating voltage is supplied. It's usually connected to the AC supply

hope this helps

6 0

3 years ago

Read 2 more answers