Answer:
Einstein realized that the energy in electrons was caused by the frequency of light and not the intensity of light. This made him realize that he needed to explain the photoelectric effect.
Explanation:
Einstein realized that the photoelectric effect was a system that should be studied and explained in more depth, when he saw how the energy of electrons behaved in the presence of light. He saw that this energy depends entirely on the frequency of light and not on the intensity of light. From this observation, he realized that the photoelectric effect was essential for the production of an electric energy system, through light energy, such as solar energy.
It is important to note that the photoelectric effect refers to the ejection of electrons on a light surface that comes into contact with a light source.
Answer EIGHT questions.
1(a) Whai do you mean by generation of computer? Describe brieíly
5
about third and fourth generations of computer.
B
moga dele
Answer:
Generation in computer terminology is a change in technology a computer is/was being used. Initially, the generation term was used to distinguish between varying hardware technologies. Nowadays, generation includes both hardware and software, which together make up an entire computer system.
5 generation of computer
Main electronic component: based on artificial intelligence, uses the Ultra Large-Scale Integration (ULSI) technology and parallel processing method.
ULSI – millions of transistors on a single microchip
Parallel processing method – use two or more microprocessors to run tasks simultaneously.
Language – understand natural language (human language).
Power – consume less power and generate less heat.
Speed – remarkable improvement of speed, accuracy and reliability (in comparison with the fourth generation computers).
Size – portable and small in size, and have a huge storage capacity.
Input / output device – keyboard, monitor, mouse, trackpad (or touchpad), touchscreen, pen, speech input (recognise voice / speech), light scanner, printer, etc.
Example – desktops, laptops, tablets, smartphones, etc.
3 generation of computer
Main electronic component – integrated circuits (ICs)
Memory – large magnetic core, magnetic tape / disk
Programming language – high level language (FORTRAN, BASIC, Pascal, COBOL, C, etc.)
Size – smaller, cheaper, and more efficient than second generation computers (they were called minicomputers).
Speed – improvement of speed and reliability (in comparison with the second generation computers).
Input / output devices – magnetic tape, keyboard, monitor, printer, etc.
Examples – IBM 360, IBM 370, PDP-11, UNIVAC 1108, etc.
4 generations of computer
Main electronic component – very large-scale integration (VLSI) and microprocessor.
VLSI– thousands of transistors on a single microchip.
Memory – semiconductor memory (such as RAM, ROM, etc.)
RAM (random-access memory) – a type of data storage (memory element) used in computers that temporary stores of programs and data (volatile: its contents are lost when the computer is turned off).
ROM (read-only memory) – a type of data storage used in computers that permanently stores data and programs (non-volatile: its contents are retained even when the computer is turned off).
Programming language – high level language (Python, C#, Java, JavaScript, Rust, Kotlin, etc.).
Carbon disulfide is formed by the reaction of coke (carbon) with sulfur dioxide. How many moles of CS2 will be generated if 8.0 moles of coke react with a surplus of sulfur dioxide? 5C +2502 - CS2 + 4CO A. 0.8 moles B. 1.6 moles C. 3.2 moles OD. 6.4 moles
I don’t know what Ksp and Kf are stand for?
Answer:
Sorry but I know only what ksf stand for
Explanation:
Ksf stand for solubility product constant
Answer:
ksp stands for solubility product constant .
kf stands for molal freezing point depression constant ..
Explanation:
KSP = The solubility product constant, Ksp, is the equilibrium constant for a solid substance dissolving in an aqueous solution. It represents the level at which a solute dissolves in solution. The more soluble a substance is, the higher the Ksp value it has .
KF = Kf is a constant for a given solvent. Kf is called the molal freezing point depression constant and represents how many degrees the freezing point of the solvent will change when 1.00 mole of a nonvolatile nonionizing (nondissociating) solute dissolves in one kilogram of solvent.
Draw a formula for Thr-Gly-Ala (T-G-A) in its predominant ionic form at pH 7.3. You may assume for the purposes of this question that the pKa values of the acidic groups of amino acid residues in the peptide are the same as in the amino acid itself.
Answer:
gggggggggg
Explanation:
gggggggg
The tripeptide formed from threonine, glycine and alanine is neutral at the pH of 7.3. The carboxylic end is negative charged by donating its proton to form the NH₃⁺ group.
What is peptide?Peptides are protein units formed from two or more amino acids bonded through peptide bonds. There are essential and non-essential amino acids. Essential amino acids have to be uptake from food and non-essential amino acids are synthesized inside the body.
Threonine is an essential amino acid with a CH₃CHOH side group. Glycine has the simplest side group hydrogen and alanine has CH₃ side chain. Both glycine and alanine are non-essential amino acids.
Each amino acids are represented with a three letter code or one letter symbol. Thus threonine is T, G for glycine and A for alanine. At a pH of 7.3 the peptide formed from these amino-acids contains a negatively charged carboxylic end.
A positively charged amino end made by protonation from the acid group make the overall charge zero. The structure of the peptide is given in the uploaded image.
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Karl-Anthony is trying to plate gold onto his silver ring. He constructs an electrolytic cell using his ring as one of the electrodes. He runs this cell for 94.3 minutes at 205.3 mA. How many moles of electrons were transferred in this process
Answer:
0.012 moles of electrons were transferred
Explanation:
We can find the number of electrons transferred from the time in seconds and the current in Amperes using the equation:
n = I*t / F
Where n are moles of electrons transferred
I is current in Amperes = 0.2053A
t is time in seconds:
94.3min*(60s/1min) = 5658s
F is faraday constant 96485A*s/mol
Replacing:
n = 0.2053A*5658s / 96485A*s/mol
n = 0.012 moles of electrons were transferred
Moles are the mass per unit molar mass of compound. The number of moles of electrons that are transferred is 0.012 moles.
What is an electrolytic cell?An electrolytic cell is a type of electrochemical cell that uses electrical energy from external sources to conduct the chemical energy in a cell.
The moles transferred in electrolytic cells are measured as:
[tex]\rm n = \rm \dfrac{I\times t}{F}[/tex]
Given,
Current (I) in amperes = 0.2053 A
Time (t) in seconds = 5658 sec
Faraday constant (F) = 96485 A -s/mol
Substituting values in the equation above moles (n) can be calculated as:
[tex]\begin{aligned} \rm n &= \dfrac{ 0.2053 \times 5658 }{96485}\\\\&= 0.012 \;\rm mol\end{aligned}[/tex]
Therefore, 0.012 moles are transferred in this process.
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arrange the metals sodium,copper, and magnesium in the decreasing order of their reactivity
Answer:
sodium>magenisium>copper
A solution is made by mixing 34.5 g of sugar with 75.0 g of water. What is the mass percent of sugar in this solution?
Please explain and show work.
the mass percent of sugar in this solution is 46%.
Answer:
Solution given:
mass of solute=34.5g
mass of solvent=75g
mass percent=[tex]\frac{mass\:of\:solute}{mass\:of \:solvent}*100\%[/tex]
=[tex]\bold{\frac{34.5}{75.0}*100\%=46\%}[/tex]
We know that,
[tex]mass \: solute = \frac{mass \: of \: solute}{mass \: of \: solvent} [/tex]×100
[tex] \frac{34.5}{75.0} = 0.46[/tex]
hope it helps..
Dylan has a coworker who is always showing up late and then not finishing his work on time . It's frustrating the other members of the team . What can he do that might help the situation ? a ) Complain about the coworker to other team members b ) Ask his coworker if he understands his job responsibilities c ) Tell his boss that the coworker is slacking off d ) Complete his coworker's work for him
What minimum mass of HCl in grams would you need to dissolve a 2.2 g iron bar on a
padlock?
2.8 g is the minimum mass of HCl in grams that would you need to dissolve a 2.2 g iron bar on a padlock.
What is dissolution?When a solute is dissolved in a solvent, a solution is created. Dissolution is the process through which solutes, or dissolved parts, combine to form a solution inside a solvent. In this procedure, the gas, liquid, or solid dissolves inside the original solvent and forms a solution.
In some polymer applications, dissolution is also an issue since it results in swelling, a loss of strength and stiffness, and a change in volume. Whether a chemical process is man-made or natural, dissolution is crucial. Catalysts are tested using dissolution. 2.8 g is the minimum mass of HCl in grams that would you need to dissolve a 2.2 g iron bar on a padlock.
Therefore, 2.8 g is the minimum mass of HCl in grams that would you need to dissolve a 2.2 g iron bar on a padlock.
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How many moles of Cl− are in 5.76 mg of FeCl3?
Answer:
0.0061650760770388 mole
What is the oxidation state for bh3
Answer:
As hydrogen is more electronegative than boron, in BH3 the oxidation number of hydrogen should be taken as -1. (E. N. of B = 2.0 & E. N. of H = 2.1)
Suppose, oxidation number of B is x.
So, we can write, x + 3*(-1) = 0
=> x = +3
Therefore, oxidation num
Explanation:
As hydrogen is more electronegative than boron, in BH3 the oxidation number of hydrogen should be taken as -1. (E. N. of B = 2.0 & E. N. of H = 2.1)
Suppose, oxidation number of B is x.
So, we can write, x + 3*(-1) = 0
=> x = +3
Therefore, oxidation num
Select True or False: The equilibrium constant for the chemical equation 2NO(g) O2(g) 2NO2(g) is two times the equilibrium constant for the chemical equation NO(g) 1/2O2(g) NO2(g).
Answer:
False
Explanation:
The first reaction is;
NO(g) + 1/2O2(g) ---->NO2(g)
K= [NO2]/[NO] [ O2]^1/2
The second reaction is;
2NO(g) + O2(g) ---->2NO2(g)
K'= [NO2]^2/[NO]^2 [O2]
It now follows that;
K'= K^2
Hence the statement in the question is false
Determine
the
number
of grams of C4H10
that
are
required
to
completely
react
to
produce 8.70 mol of CO2
according
to
the
following
combustion
reaction:
2 C₄H₁₀(g)
+
13 O₂(g)
→
8 CO₂(g)
+
10 H₂O(g)
Answer:
8 CO₂(g)
Explanation:
just took the exam
A runner completes the 300-meter dash in 38 seconds. What is the speed of the runner? Round your answer to the nearest tenth.
Answer:
x= 300m , 38s
answer is 7.9
Answer:
speed=distance/time
Explanation:
speed=300/38
=7.8947368421
to the nearest tenth=7.9
The elementary reaction 2H2O(g)↽−−⇀2H2(g)+O2(g) proceeds at a certain temperature until the partial pressures of H2O, H2, and O2 reach 0.0900 bar , 0.00100 bar , and 0.00350 bar respectively. What is the value of the equilibrium constant at this temperature?
Answer:
3.89 ×10^-5
Explanation:
Since they are gaseous reactants, we obtain the equilibrium constant from the given partial pressures;
p(H2O) = 0.0900 bar
p(H2) = 0.00100 bar
p(O2) = 0.00350 bar
The equation of the reaction is;2H2O(g)⇄2H2(g)+O2(g)
Kp= p(H2) . p(O2)/p(H2O)
Kp= 0.00100 × 0.00350/0.0900
Kp= 3.89 ×10^-5
A solution has a higher boiling point than its associated pure solvent does.
What is this property of the solution called?
1. boiling-point depression
2. freezing-point depression
3. vapor-pressure lowering
4. boiling-point elevation
Answer:
4 boiling point elevation
Carboxylic acids and alcohols react via dehydration and condensation to produce a/an _______ and water.
Question options:
amine
ether
polymer
ester
Answer:
ester
Explanation:
Carboxylic acids and alcohols react in the presence of strong acid to produce an ester and water. The two carbon chains come together, which is the condensation, and then water is generated, which is dehydration. The resulting compound is an ester.
Is pre ap chemistry hard in high school?
If you don't practice enough it's obviously going to be hard but if you practice enough it's going to be a piece of cake so don't think if it's going to be hard or not just think it's going to be worth the try at the very end
Explain the working principle of a clinical thermometer
Answer:
A clinical thermometer is a thermometer used to measure human body temperature. Most made in the 20th century are mercury-in-glass thermometers. They are accurate and sensitive, having a narrow place where the mercury level rises very fast. A kink in the tube stops the mercury level from falling on its own.
Sodium acetate
NaC2H3O2
SC2H3O2
Na2C2H3O2
Answer:
Sodium acetate is NaC2H3O2
Answer:
The answer is A for the lazy people.
A) Draw a conclusion about the relationship between enzyme activity and reaction temperature.
B) Provide an explanation for why we see a flattening of the curve for the 75 degree reaction after 3 minutes.
Answer:
Direct relationship.
Explanation:
There is direct relationship between enzyme activity and temperature of reaction. Direct relationship means if one factor is increases the other factor is also increase and vice versa. In chemical reactions, the rate of an enzyme action increases as the temperature of the chemical reaction also increases. we see a flattening of the curve for the 75 degree reaction after 3 minutes because the enzyme action is not working at that temperature or in other words, this temperature is not suitable for the enzyme activity.
6) Hydrogen gas can be generated from the reaction between aluminum metal and hydrochloric acid:
2 Al(s) + 6 HCl(aq) + 2 AICI3, (aq) + 3 H2(g)
a. Suppose that 3.00 grams of Al are mixed with excess acid. If the hydrogen gas produced is directly collected
into a 850 mL glass flask at 24.0 °C, what is the pressure inside the flask (in atm)?
b. This hydrogen gas is then completely transferred from the flask to a balloon. To what volume (in L) will the
balloon inflate under STP conditions?
c. Suppose the balloon is released and rises up to an altitude where the temperature is 11.2 °C and the pressure is
438 mm Hg. What is the new volume of the balloon (in L)?
Stoichiometry refers to the relationship between the moles of reactants and products.
This question must be solved using both stoichiometry and the gas laws
The reaction equation is;
2 Al(s) + 6 HCl(aq) --------> 2 AICI3, (aq) + 3 H2(g)
Using stoichiometryNumber of moles of Al = 3g/27g/mol = 0.11 moles
According to the reaction equation;
2 moles of Al yields 3 moles of H2
0.11 moles of Al yields 0.11 * 3/2 = 0.165 moles
Using the gas lawsFrom the ideal gas equation;
PV=nRT
P = ?
n= 0.165 moles
V = 0.85 L
T = 297 K
R = 0.082 atmLK-1mol-1
P= nRT/V
P = 0.165 * 0.082 * 297/0.85
P= 4.73 atm
Under STP conditions;P1 = 4.73 atm
T1 = 297 K
V1 = 0.85 L
P2 = 1 atm
T2 =273 K
V2 =?
From the general gas equation;P1V1/T1 = P2V2/T2
P1V1T2 = P2V2T1
V2 = P1V1T2/P2T1
V2 = 4.73 * 0.85 * 273/1 * 297
V2 = 3.69 L
P1 = 760 mmHg
T1 = 273 K
V1 = 3.69
P2 = 438 mm Hg
T2 = 284.2 K
V2 =?
P1V1/T1 = P2V2/T2
P1V1T2 = P2V2T1
V2 = P1V1T2/P2T1
V2 = 760 * 3.69 * 284.2/438 *273
V2 = 797010.48/119574
V2= 6.67 L
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Which is the best interpretation of the two flat portions of the graph?
In those portions, the heat supplied to the substance by the heater does not lead to a temperature rise as intermolecular forces are broken.
When a substance is heated, we normally expect that its temperature will rise as a consequence.
However, heat may be supplied to a substance but its temperature does not rise owing to the fact that the heat energy supplied is used to break intermolecular bonds.
This occurs during fusion and boiling. The heat supplied at these point does not result in temperature rise since it is used to break intermolecular bonds. The temperature remains steady during these processes as shown by the two flat portions on the graph in the image attached to the question. This heat supplied is known as the latent heat.
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Answer:
The answer for me was "These show where changes of state are occuring"
Explanation:
I got it right
(URGENT FOR BRAINLIEST!!)
The diagram below shows the movement of Earth plates.
The picture shows two Earth plates one beside the other. The plate on the left is shown moving towards the right and the plate
Which of these features is most likely formed as a result of the movement of Earth plates shown in the diagram? (2 points)
a canyon
a fault
a mountain
a ridge
Answer:
mountain
Explanation:
when plates move towards each other they create mountains
The mass of a container is determined to be 1.2 g. A sample of a compound is transferred to this container, and the mass of the compound plus the container is determined to be 3.06 g. The mass of the compound should be reported as:__.
Answer:
Sorry I don't know what you
According to law of conservation of mass as mass is neither created nor destroyed mass of compound should be reported as 1.86 g that is by subtracting mass of compound from mass of compound and container.
What is law of conservation of mass?According to law of conservation of mass, it is evident that mass is neither created nor destroyed rather it is restored at the end of a chemical reaction .
Law of conservation of mass and energy are related as mass and energy are directly proportional which is indicated by the equation E=mc².Concept of conservation of mass is widely used in field of chemistry, fluid dynamics.
Law needs to be modified in accordance with laws of quantum mechanics under the principle of mass and energy equivalence.This law was proposed by Antoine Lavoisier in the year 1789.
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Each 5-ml teaspoon of Extra Strength Maalox Plus contains 450 mg of magnesium hydroxide and 500 mg of aluminum hydroxide. How many moles of hydronium ions H3O are neutralized by 1 teaspoon of antacid product?
Answer:
0.0347 moles of hydronium ions
Explanation:
The equation of the neutralization reaction between hydroxide and hydronium ions is given below:
H₃O+ (aq) + OH- (aq) ----> 2 H₂O (l)
From the equation above, 1 mole of hydroxide ions will neutralize one mole hydronium ions.
The moles of hydroxide ions present in 1 teaspoon or 5 mL of antacid product is calculated as follows:
Number of moles = mass / molar mass
Molar mass of Magnesium hydroxide, Mg(OH)₂ = 58 g/mol
Molar mass of aluminium hydroxide, Al(OH)₃ = 78 g/mol
Mass of magnesium hydroxide = 450 g = 0.45 g
Mass of aluminium hydroxide = 500 mg = 0.5 g
Moles of magnesium hydroxide = (0.45/58) moles
Moles of aluminium hydroxide = (0.5/78) moles
Equation of the ionization of magnesium hydroxide and aluminium hydroxide is given below:
Mg(OH)₂ (aq) ----> Mg²+ (aq) + 2 OH- (aq)
Al(OH)₃ (aq) ---> Al³+ (aq) + 3 OH- (aq)
Number of moles of hydroxide ions present in (0.45/58) moles of magnesium hydroxide = 2 × (0.45/58) moles = 0.0155 moles
Number of moles of hydroxide ions present in (0.5/78) moles of aluminium hydroxide = 3 × (0.5/78) moles = 0.0192 moles
Total moles of hydroxide ions = 0.0155 + 0.0192 = 0.0347 moles hydroxide ions
Therefore, 0.0347 moles of hydroxide ions will neutralize 0.0347 moles of hydronium ions.
Amphiphilic molecule: ___________
a. have both oxidizing and reducing groups.
b. are micelles.
c. have chromophores in two different wavelength regions.
d. have both acidic and basic groups.
e. have both hydrophilic and hydrophobic groups.
How many Noble gases we have in Periodic Table???
Answer:
Six
Explanation:
5. How many moles are present in 4.20x10^24 atoms of Pb
Explanation:
[tex]57816 \: moles[/tex]
are present in 4.20x10^24 atoms of Pb
Answer:
7 moles
Explanation:
(4.2*10^24)/(6*10^23)=7
equal volumes 50.0 ml of 0.54897 m solution of HCL and 0.9573 M NaOH solution have an initial temperature of 18.5 degrees Celsius react in a coffee cup calorimeter the resulted Solutions records a temperature of 22.9 degrees Celsius since the solutions are mostly water the solution are assumed to have a density of 1.0 g per ml and a specific heat of 4.184 joules per gram degree celsius the heat capacity of the Colorimeter is 1.0 x 10 to power 1 joules per degrees Celsius calculate the heat and gained or released by the solution at a constant pressure in J
Answer:
Explanation:
ok
