The PC modem was invented in what year?​

Answers

Answer 1

Answer:

1977

Explanation:

Getting connected: a history of modems. Then, in 1977, Dale Heatherington and Dennis Hayes created the world's first PC modem, the 80-103A.


Related Questions

10.0 grams of a gas occupies 12.5 liters at a pressure of 42.0 mm Hg. What is the volume when the pressure has increased to 75.0 mm Hg? 6.72 L 7.00 L 22.3 L 0.143 L

Answers

Answer:  7.00 L

Explanation:

Boyle's Law: This law states that pressure is inversely proportional to the volume of the gas at constant temperature and number of moles.

[tex]P\propto \frac{1}{V}[/tex]     (At constant temperature and number of moles)

[tex]P_1V_1=P_2V_2[/tex]  

where,

[tex]P_1[/tex] = initial pressure of gas  = 42.0 mm Hg

[tex]P_2[/tex] = final pressure of gas  = 75.0 mm Hg

[tex]V_1[/tex] = initial volume of gas   = 12.5 L

[tex]V_2[/tex] = final volume of gas  = ?

[tex]42.0\times 12.5=75.0\times V_2[/tex]  

[tex]V_2=7.00L[/tex]

Therefore, the volume  when the pressure has increased to 75.0 mm Hg is 7.00 L

Using the electronegativity chart below, determine which compound would have the highest polarization

A. Li-O
B. B-F
C. H-CI
D. Be-Br

Answers

Answer:

A. Li-O

Explanation:

The highest polarization will occur between the atoms of  Li-O because they have the most electronegativity difference between them.

Polarization occurs when there is a separation of charge between the atoms of heteronuclear molecules.

The electronegativity gives the tendency for an atom to attract the electrons within the bond pair to itself.

To know the atom with most polarization, it has to be one with highest electronegativity difference. Li and O have the highest difference. Also, since the bond is between a metal and non-metal, it is obviously the most polarized.


12.4 g of phosphorus reacts with 9.6 g of oxygen.
Which of the following chemical equation represents this reaction?
[Relative atomic mass: P, 31; 0, 16]
A P + O2 + PO2
B 2 P + O2 + 2 PO
C 3P +2 02 → P304
D 4P +3 02 → 2 P203​

Answers

Answer:

D 4P +3O₂ → 2 P₂O₃

Explanation:

In this problem, we need to convert the mass of phosphorus and oxygen to moles trying to find the ratio of reaction (The moles of P that reacts per mole of O₂):

Moles P:

12.4g P * (1mol P / 31g) = 0.4 moles

Moles O₂:

9.6g * (1mol / 32g) = 0.3 moles

The ratio of reaction is:

0.4 mol / 0.3 mol = 1.33 = 4 moles of P / 3 moles of O₂

That means 4 moles of P react with 3 moles of O₂ and the reaction that represents this ratio is:

D 4P +3O₂ → 2 P₂O₃

The reaction of 12.4 g Phosphorous with 9.6 grams of Oxygen will be represented as [tex]\rm 4\;P\;+\;3\;O_2\;\rightarrow\;2\;P_2O_3[/tex]

In a chemical equation, the stoichiometric values are the moles of the molecules involved in the reaction. For the reaction of Phosphorous and oxygen, the moles of both elements are to be calculated.

Moles = [tex]\rm \frac{weight}{molecular\;weight}[/tex]

Moles of Phosphorous = [tex]\rm \frac{12.4}{31}[/tex]

Moles of Phosphorous = 0.4

Moles of oxygen = [tex]\rm \frac{9.6}{16}[/tex]

Moles of oxygen = 0.6

Moles of [tex]\rm O_2[/tex] = 0.3

The equation will be:

[tex]\rm 0.4\;P\;+\;0.3\;O_2\;\rightarrow\;2\;P_2O_3[/tex]

[tex]\rm 4\;P\;+\;3\;O_2\;\rightarrow\;2\;P_2O_3[/tex]

The correct reaction will be D.

For more information about the chemical equation, refer the link:

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how many atoms are in a compound

Answers

Answer:

Compounds are made of two or more atoms of different elements,

Explanation:

Answer:

6.022×1023 atoms —1.00 mol of atoms.

Explanation:

Please Help!

Which change takes place at the freezing point of a substance?
Group of answer choices
A. A gas becomes a liquid
B. A solid becomes a gas
C. A liquid become a solid
D. A gas becomes a solid

please also give me an explanation since I do not understand this.

Answers

The correct answer is b

Answer:

C. A liquad becomes a solid

Explanation:

When you freeze water its a scientific fact that it becomes solid.

Information about calcium carbonate
What is calcium carbonate?

Answers

Answer:

Calcium carbonate is a dietary supplement used when the amount of calcium taken in the diet is not enough. Calcium is needed by the body for healthy bones, muscles, nervous system, and heart. Calcium carbonate also is used as an antacid to relieve heartburn, acid indigestion etc.

... yes I copied this from the internet, but hope it helps !

Calcium carbonate is a chemical compound with the formula CaCO₃. It is a common substance found in rocks as the minerals calcite and aragonite and is the main component of pearls and the shells of marine organisms, snails, and eggs.

Plants give off oxygen as part of photosynthesis. Explain the impact of this process on humans?

Answers

Answer:

i think it haven't impact because oxygen is very sensitive for our life and from plants there is so many kinds of food sources soo

Determine the number of grams in each of the quantities

1.39.0 x 1024 molecules Cl2

Answers

Mass of Cl₂ : 164.01 g

Further explanation

A mole is a number of particles(atoms, molecules, ions)  in a substance

This refers to the atomic total of the 12 gr C-12  which is equal to 6.02.10²³, so 1 mole = 6.02.10²³ particles  

Can be formulated :

N = n x No

N = number of particles

n = mol

No = 6.02.10²³ = Avogadro's number

mol Cl₂ :

[tex]\tt n=\dfrac{N}{No}\\\\n=\dfrac{1.39.10^{24}}{6.02.10^{23}}\\\\n=2.31[/tex]

mass Cl₂(MW=71 g/mol) :

[tex]\tt mass=mol\times MW\\\\mass=2.31\times 71=164.01[/tex]

Answer:

hui

Explanation:

I have no idea how to do these help me plz

Answers

for me the pictures aren't clear

A decrease in temperature decreases
. The reaction rate will

Answers

Answer:

The reaction rate decreases with a decrease in temperature. ... Molecules joined by stronger bonds will have lower reaction rates than will molecules joined by weaker bonds, due to the increased amount of energy required to break the stronger bonds.

Worth a lot of points. Please only answer if u know the question. Thanks

Answers

Answer:

#7 is D. #4 is B. #5 is 13 #6 is C

Answer:

okokokokokokokok I will answer in just a moment

Explanation:

A solution is

Question 6 options:



a homogeneous mixture.




a compound.




chemically separable.




a heterogeneous mixture.

Answers

Answer:

the first one. a homogeneous mixture.

Explanation:

hope this helps :)

What did you include in your response? Check all that
apply.
O No, thermal energy is not being transferred by
radiation in this image.
O The eggs are in direct contact with the metal pan,
which is in direct contact with the gas flame.
O Thermal energy is being transferred by conduction.
O Radiation transfers thermal energy by
electromagnetic waves.
O Radiation does not transfer thermal energy by
direct contact.

Answers

If you included all of them, check all
I’m just gonna explain it okay so if you included it in you paragraph response just check it off there is no right or wrong

Temperature of boiling water cannot be measured by a
_____________ thermometer.

Answers

Answer:

Cannot be measured by pyrometer.

Explanation:

This is because a pyrometer measures temperatures for very hot bodies such as the sun.

Answer:

Clinical

Explanation:

Temperature of boiling water cannot be measured by a Clinical thermometer The reason behind this is that the range of clinical thermometer varies between only 35° C to 42° C.

What is the mass of hydrogen produced when 8.0 g of sodium
reacts with an excess of water to produce hydrogen and sodium
hydroxide? The equation is given.
2 Na + 2 H2O → 2NaOH + H2

Answers

Answer:

Mass = 0.35 g

Explanation:

Given data:

Mass of sodium = 8.0 g

Mass of hydrogen produced = ?

Solution:

Chemical equation:

2Na + 2H₂O     →    2NaOH + H₂

Number of moles of sodium:

Number of moles = mass/molar mass

Number of moles = 8.0 g/ 23 g/mol

Number of moles = 0.35 mol

now we will compare the moles of sodium and hydrogen

             Na           :           H₂

             2             :            1

           0.35          :      1/2×0.35 = 0.175 mol

Mass of hydrogen:

Mass = number of moles × molar mass

Mass = 0.175 mol × 2 g/mol

Mass = 0.35 g

Why dont people brush their teeth?Like some be going around people and everything,UGHHHHH!

Please tell me

Answers

Answer:

like so true just brush your teeth... if you can't afford it then no disrespect to you

Explanation:

Answer:

their fault when the grow up and have yellow teeth + dentures and they are like 28 XD  

Explanation:

ANSWER ASAP please I need help thank you I’ll give you brainly

What is the standard cell notation of a galvanic cell made with silver (Ag) and
nickel (Ni)?
A. Ni2+(aq) | Ni(s) || Ag(s) | Ag+(aq)
B. Agt(aq) | Ag(s) || Ni(s) | Ni2+(aq)
C. Ag(s) | Ag+(aq) || Ni2+(aq) | Ni(s)
D. Ni(s) | Ni2+(aq) || Ag+(aq) | Ag(s)

Answers

Answer:

See the attached notation!

How do the particies in a liquid create surface
tension?

Answers

It's been a while since I've taken Chemistry but here's what I know:

There are small, weak bonds that form between water molecules. These bonds make it so liquid molecules (water, in this example) cannot move as freely as a gas, but their bonds aren't nearly as strong as a solid. The bonds are formed when a hydrogen atom is attracted to an oxygen atom (because they have an opposite charge). This bond plus the gas molecules hitting the water causes surface tension.

(Let me know if this is wrong and I hope you have a lovely day!!)

In which material would the particles be closest together?
O Syrup
O Brick
O Air
O Water

Answers

I think air but if wrong sorry

Answer:

Brick

Explanation:

The distance between particles is best determined by density. So, to find which material has the most compacted particles, we need to find which material has the highest density. Solids will always have the highest densities, so Brick would have the particles that are closest together.

Plants don't grow as well when ____ has been lost.
a.
clay
c.
parent rock
b.
topsoil
d.
slope

Answers

Answer

the answer is b

explanation

Answer:

b. topsoil

Explanation:

I just took the test

3. Which of the following is an example of a polyatomic ion?
a. NO
b. OP-
C. CI
d. Ca²+​

Answers

Answer:D

Explanation:polyatomic means more then one and it have more then 1 positive ion

Answer: B

Explanation:

A polyatomic ion needs to have two atoms, hence the word “poly,” so D and C are NOT correct. An ion also needs to be charged, so that makes B the correct answer.

What is the force of attraction between two atoms that are combined?

a. chemical bond
b. atomic bond
c. physical property
d. magnetic bond

Answers

Answer:

a

Explanation

Chemical bond refers to the forces holding atoms together to form molecules and solids. This force is of an electric nature, and the attraction between electrons of one atom to the nucleus of another atom contributes to what is known as chemical bonds.

EXPLAIN What is one way that the thermal energy of a system can be changed?

Answers

Answer:

When the temperature of an object increases, the average kinetic energy of its particles increases. When the average kinetic energy of its particles increases, the object's thermal energy increases. Therefore, the thermal energy of an object increases as its temperature increases.

Explanation:

BTW I GOT THE ANSWER FROM KRISTINA

The thermal energy of a system is the amount of heat energy in it.

One way to change thermal energy is by alter the system by introducing a new object to the system.

The thermal energy of a system is calculated using:

[tex]E = \frac 12 mc\theta[/tex]

Assume the mass of the system remains unchanged.

When an object is introduced to the system, the thermal energy becomes:

[tex]E_2 = \frac 12 mc(\theta + \alpha)[/tex]

Where:

[tex]\alpha \ne 0[/tex] --- the temperature of the object.

Expand:

[tex]E_2 = \frac 12 mc(\theta) + \frac 12 mc (\alpha)[/tex]

Substitute: [tex]E = \frac 12 mc\theta[/tex]

[tex]E_2 = E + \frac 12 mc (\alpha)[/tex]

This means that the thermal energy of the system will change by the thermal energy of the object that is being introduced to the system.

Hence, one way the thermal energy can be changed is to introduce a new object (or matter).

Read more about thermal energy at:

https://brainly.com/question/18989562

PLZ FASTLEY ANSWER The images show two metamorphic rock samples.


Left: light colored rock with coarse texture. Right: red and white rock with rounded grains and coarse texture.


Which statement accurately describes these rocks?


Both rocks are non-foliated.

Neither rock has randomly arranged grains.

Both rocks formed at Earth’s surface.

Neither rock formed through extreme heat or pressure.

Answers

Answer:

a

Explanation:

From the given images, it is clear that both rocks are non-foliated rocks because they don't have distinct repetitive layers.  Hence option a is correct.

What are metamorphic rocks?

Metamorphic rocks are formed through intense pressure and heating from the sedimentary or igneous rocks. Sometime the change n heat or pressure make the metamorphic rocks gets foliated.

Foliation occurs when pressure forces flat or elongate minerals within a rock to align. These rocks form a platy or sheet-like structure that reflects the pressure direction. There is no platy or sheet-like structure in non-foliated metamorphic rocks.

Non-foliated rocks can be created in a variety of ways. Some rocks, like limestone, are composed of minerals that are not flat or elongate. Therefore, the given rocks are non-foliated.

To find more on foliated rocks, refer here:

https://brainly.com/question/1984747

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The two rate statements below are not the same. Use the concept of unit rates to explain
the difference.
a. LaVerne earns $10 in 2 hours.
b. Shirley earns $2 in 10 hours.

Answers

It’s definitely B but I’m not sure

What is the unit for the answer?
23.67 boops
x
0.256 snoots
35 boops
Х
520. zoinks
Х
92 snoots
2
218 snoots
34 wout
Х
2
8765 wows
345 zoinks
boops
snoots
WOWS
zoinks
wows/snoots
boops/zoinks

Answers

Answer:Answer to: A function f is defined on the interval ~[0,4], and its derivative is { e^{sinx} - 2cos3x } a. on what interval is f increasing? b....

Missing

Explanation:

How does dermal tissue play a key role in transpiration?

Answers

Answer:

Dermal tissue of the stems and leaves is covered by a waxy cuticle that prevents evaporative water loss. Stomata are specialized pores that allow gas exchange through holes in the cuticle. Unlike the stem and leaves, the root epidermis is not covered by a waxy cuticle which would prevent absorption of water.

Explanation:

Which answer choice correctly lists only elements?

A
Cl, Na, CH3, Ne
B
Mg, NO2, Mg, B
C
H2O, Li, N, I2
D
N2, O2, Al, Zn
Group of answer choices

A

Answers

Answer:

D

Explanation:

Nitrogen^2, Oxygen^2, Aluminum, Zinc

the others have combination

I’ll marmark you brainlist

Answers

it's B! hope this helped! <3

How do SMRs provide more flexibility than ordinary nuclear reactors?

Select all that apply.

More reactors can be installed at a location as the energy demand increases.

Power plants can be built to fit locations with less demand or less space.

The SMRs can use multiple types of fuel and recycle byproducts if needed.

The SMRs can adjust their energy output using coolants and control rods.

Answers

Answer:

The SMRs can adjust their energy output using coolants and control rods.

Power plants can be built to fit locations with less demand or less space.

Explanation:

I think that it is but I am not sure.

Power plants can be built to fit locations with less demand or less space. The SMRs can adjust their energy output using coolants and control rods. The correct options are B and D.

What are SMRs?

A wireless communications technology that competes with traditional cellular services. The base station equipment supplier is the transmitter licensee in an SMR system.

Power plants can be built to accommodate locations with low demand or limited space. Coolants and control rods allow SMRs to adjust their energy output.

These advanced reactors, which are expected to range in size from tens to hundreds of megawatts, can be used for power generation, process heat, desalination, or other industrial applications.

Light water or other non-light water coolants, such as a gas, liquid metal, or molten salt, may be used as a coolant in SMR designs.

Thus, B and D are correct options.

For more details regarding modularity, visit:

https://brainly.com/question/11797076

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