Answer:
They usually lose electrons to form ions with 2 positive charges
Explanation:
Answer:
ptic fiber communication and satellite communication are the leading technologies which are revolutionizing the world of telecommunications. Both technologies have their advantages and limitations which make them suitable for certain type of applications. This article will provide an overview of optic fiber and satellite communication technologies and present a comparison of the features and related issues.
Optic Fiber Communication
Optic Fiber communication transmits information by sending pulses of light (using laser) through an optic fiber. The low signal loss in optic fibers and high data rate of transmission systems, allow signals with high data rates (exceeding several Gbps) to travel over long distances (more than 100 km) without a need of repeater or amplifier. Moreover, using wavelength division multiplexing (WDM) allows a single fiber to carry multiple signals (upto 10 different signals) of multi-Gbps transmissions. Optic Fiber communication offers extremely high bandwidth, immunity to electromagnetic interference, non-existent delays and immunity from interception by external means. In the 1980s and 1990s, the continents were linked together using undersea optic fiber bringing about a paradigm shift in the global telecommunications.
These advancements in optic fiber communication has resulted in decrease of satellite communications for several types of communications. For instance, transmission between fixed locations or point-to-point communications, where large bandwidths are required (such as transoceanic telephone systems) are made through optic fiber instead of using satellite communication. Optic Fiber communication is also used to transmit telephone signals, Internet communication, LAN (Gigabit LAN) and cable television signals.
Satellite Communication
Satellite communications use artificial satellites as relays between a transmitter and a receiver at different locations on Earth. Satellite systems allow users to bypass typical carrier offices and to broadcast information to multiple locations. Communications satellites are used for radio, TV, telephone, Internet, military and other applications. There are more than 2,000 satellites around Earth’s orbit, being used for communication by both government and private organizations.
Communication Satellites are LOS (line-of-sight) microwave systems with a repeater. These satellites rotate around the earth with the speed of earth and are known as geostationary satellites. The limitations of antenna size also limits focusing capability making the coverage for a single satellite transmitter very large. This makes satellite communication ideal for TV and radio services as the signal has to flow from a single point to many points in a single direction. The large distance of satellites from the earth (about 22,300 miles) results in delays which adversely effects two-way communication like mobile conversations. Low earth orbit satellites can be used for two-way mobile communication because less power is required to reach those satellites.
Explanation:
After 100years, sample is 250g
After 200 years, sample is 125g
After 300years, sample is 62.5 g
Answer:
A. for K>>1 you can say that the reaction is nearly irreversible so the forward direction is favored. (Products formation)
B. When the temperature rises the equilibrium is going to change but to know how is going to change you have to take into account the kind of reaction. For endothermic reactions (the reverse reaction is favored) and for exothermic reactions (the forward reaction is favored)
Explanation:
A. The equilibrium constant K is defined as
In any case
aA +Bb equilibrium Cd +dD
where K is:
![K= \frac{[C]^{c}[D]^{d}}{[A]^{a}[B]^{b}}](https://tex.z-dn.net/?f=K%3D%20%5Cfrac%7B%5BC%5D%5E%7Bc%7D%5BD%5D%5E%7Bd%7D%7D%7B%5BA%5D%5E%7Ba%7D%5BB%5D%5E%7Bb%7D%7D)
[] is molar concentration.
If K>>> 1 it means that the molar concentration of products is a lot bigger that the molar concentration of reagents, so the forward reaction is favored.
B. The relation between K and temperature is given by the Van't Hoff equation
Where: H is reaction enthalpy, R is the gas constant and T temperature.
Clearing the equation for 
we get:
Here we can study two cases: when delta 
is positive (exothermic reactions) and when is negative (endothermic reactions)
For exothermic reactions when we increase the temperature the denominator in the equation would have a negative exponent so is greater that 
and the forward reaction is favored.
When we have an endothermic reaction we will have a positive exponent so will be less than the forward reactions is not favored.
The density can be calculated using the following rule:
density = mass/volume
therefore,
volume = mass/density
we have the mass=22 mg=0.022 grams and density=0.754g/cm^3
substituting in the above equation, we can calculate the volume as follows:
volume = 0.022/0.754 = 0.0291 cm^3
