Answer:
The metal surface becomes more positive as electrons are lost from it.
Explanation:
Let us note that photoelectric effect refers to a phenomenon in which electrons are ejected from a clean metal surface irradiated with light of appropriate frequency. This photon must possess a frequency above the threshold frequency of the metal and its energy must exceed the work function of the metal. When these conditions are met, electrons are emitted from a clean metal surface, having a constant kinetic energy as long as the frequency of the incident photon remains constant.
However, as photoelectric effect progresses and electrons are lost from the metal surface, the metal surface becomes more positive. The more positive the surface, the greater the attraction of the positive surface for the emitted electrons. This reduces the kinetic energy of the emitted photons even though the frequency of incident photons is held constant.
If an experiment produces 5 g but should have made 500 g, what is the percent
yield?
Answer:
Percentage of yield = 1%
Explanation:
Given:
Amount of yield = 5g
Total amount of product = 500 gram
Find:
Percentage of yield = ?
Computation:
⇒ Percentage of yield = [Amount of yield / Total amount of product]100
⇒ Percentage of yield = [5g / 500g]100
⇒ Percentage of yield = [0.01]100
⇒ Percentage of yield = 1%
Compound A (C9H12) shows prominent peaks in its mass spectrum at m/z 120 and 91. Compound B (also C9H12) shows prominent peaks at m/z 120 and 105. On vigorous oxidation with chromic acid, both compounds give benzoic acid. From this information, deduce the structures of both compounds.
Answer:
Compound A: Propylbenzene
Compound B: Cumene
Explanation:
On this case, we have two clues:
1) The mass spectrometry info
2) The formation of benzoic acid
If we have the formation of benzoic acid with a strong oxidant ([tex]H_2CrO_4[/tex]). It means that we have an alky group bonded to benzene. Therefore we have to add three carbons to a benzene ring in order to obtain the mass of the compound (120).
The next question is how these three additional carbons are bonded to the benzene. For this, we have to check the mass info. For compound A we have a fragmentation moeity on 91 therefore we have a loss of an ethyl group. Therefore compound A have a linear structure for the aditional three carbons.
For compound B we have a fragmentation moeity on 105 this means a loss of 15 units of mass therefore we loss a methyl group. This indicates that we have a non linear structure fo the three additional carbons.
See figures 1 and 2.
I hope it helps!
How many grams of lead (ll) sulfate would be produced from the complete reaction of 23.6 g lead (iV) oxide ?
Answer:
59.8287
Explanation:
I put that answer in and it is correct.
A technician prepared a solution by heating 100 milliliters of distilled water while adding KCl crystals until no more KCl would dissolve. She then capped the clear solution and set it aside on the lab bench. After several hours she noticed the solution had become cloudy and some solid had settled to the bottom of the flask. Which statement best describes what happened?
A. As the solution cooled, evaporation of water increased the KCl concentration beyond its solubility
B. Water molecules, trapped with the KCl crystals, were released after heating
C. At lower temperatures the solubility of the KCl decreased and recrystallization occurred
D. At increased temperatures the solubility of KCl increased and remained too high after cooling
Answer:
At lower temperatures the solubility of the KCl decreased and recrystallization occurred
Explanation:
Solubility refers to the amount of solute that dissolves in one litre of water at a particular temperature. Solubility is a property referring to the ability for a given substance, the solute, to dissolve in a solvent. It is measured in terms of the maximum amount of solute dissolved in a solvent at equilibrium. The resulting solution is called a saturated solution.
Solubility is dependent on temperature. This is the reason why we must state the particular temperature at which a given solubility data was collected. Above or below the quoted temperature, the solubility data may no longer be accurate.
Let's return to the question, at elevated temperatures, we can see that the KCl is very soluble in water as evidenced by the clear solution obtained at high temperature. However, as the temperature decreases, the solubility of KCl also decreases accordingly and recrystallization of the solute occurred hence the formation of a cloudy solution and the settling of some solid at the bottom of the flask.
Answer:
C. At lower temperatures the solubility of the KCl decreased and recrystallization occurred
Explanation:
Please help me with this!: Beverages such as pop and fizzy water are carbonated by dissolved CO2. Explain in detail why pop will go flat faster if the cap is left off a bottle compared to if the cap remains tightly in place. You May use diagrams if you wish.
Answer:
If the cap is left off, some of the dissolved CO2 can escape as gas from the bottle, making the pop go flat faster (less dissolved CO2 in pop). If the cap is placed tightly, the gaseous CO2 cannot readily escape the bottle thus your pop won't go flat
Explanation:
If the cap is left off, some of the dissolved CO2 can escape as gas from the bottle, making the pop go flat faster. If the cap is placed tightly, the gaseous CO2 cannot readily escape the bottle thus your pop won't go flat.
Just some fun related concept:
A similar concept comes into play for the reason behind why pop tastes better in fridge then just keeping at normal temperature. This is because gases tend to have high solubility at cold temperatures thus CO2 is more readily dissolved in fridge than outside room temperature which is why it tastes great!
What is the solution to the problem expressed to he correct number of significant figures? 12.0/7.11
Answer: The solution to the problem expressed to he correct number of significant figures is 1.69
Explanation:
Significant figures : The figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.
The rule applied for multiplication and division is :
The least precise number determines the number of significant figures in the answer.
As 12.0 has 3 significant digits and 7.11 also has 3 significant digits, the answer would also contain 3 significant digits.
For [tex]\frac{12.0}{7.11}=1.69[/tex]
Thus the solution to the problem expressed to he correct number of significant figures is 1.69
Answer:
1.69
Explanation:
12.0 ÷ 7.11 = 1.687
The rule of significant figures for division is that the quotient must have the same number of significant figures as the number that has the fewest significant figures.
Both 12.0 and 7.11 have three significant figures. Because of this, we know that we must round our quotient to three significant figures as well. 1.687 rounded to the nearest tenth is 1.69. So our answer is 1.69.
- 2022 Edmentum
How many atoms of carbon are in 4.00 moles of C6H12O6?
Answer:
Explanation:
1 mole atoms - 6,02 * [tex]10^{23}[/tex]
4 moles atoms - x
x = 4 * 6,02 * [tex]10^{23}[/tex] * 6
x = 24 * 6,02 * [tex]10^{23}[/tex]
x = 144,48 atoms ≅ 144 atoms
A velocity vs time graph is a graph that shows the relationship between the velocity of an object over time___is plotted on the x-axis in seconds, and the___of the object is plotted on the y-axis in meters per second.
Answer:
i have the same question
Explanation:
Wich substances is most likely to form in a precipitation reaction?
Answer:
A precipitation reaction refers to the formation of an insoluble salt when two solutions containing soluble salts are combined. The insoluble salt that falls out of solution is known as the precipitate, hence the reaction's name.
Explanation:
What did Ernest Rutherford's work uncover?
Answer:
Ernest Rutherford is known in his work of pioneering studies of radioactivity and the specifics in the atom. He discovered that there are two types of radiation, which are alpha and beta particles, coming from uranium. He found that the atom consists mostly of empty space, with its mass concentrated in a central positively charged nucleus.
Explanation:
hope this helps
Give TWO reasons, in terms of shielding, why potassium is the
most reactive of the three elements.
Answer:
Hi..? All three elements are in group 1 thus they have 1 valence electron which is easy to lose due to shielding.As Pottasium is larger than the rest,Pottasium's valence electron is at a greater distance from the attractive nucleus and is so removed more easily than Sodium's and Lithium's valence electrons.As it is removed more easily it requires less energy and can be said to be more reactive
Write an equation that shows the formation of a magnesium ion from a neutral magnesium atom
Answer:
Mg ---> Mg^2+ + 2e^
Explanation:
hope it helps : )
Magnesium is a neutral atom that can lose two electrons two achieve stability and forms a cation. The magnesium ion is produced as, Mg ⇒ Mg²⁺ + 2e⁻.
What is a magnesium ion?Magnesium ion is a charged species that is produced as the result of the neutral magnesium donating its electron so as to achieve its stable and complete electronic configuration.
When an atom donates an electron to another atom then they themselves become positively charged whereas the other species that accepts the electron becomes negatively charged. The positive charge is called a cation.
The reaction of the neutral magnesium donating electrons to become ions is shown as,
Mg ⇒ Mg²⁺ + 2e⁻
Therefore, magnesium loses two electrons to become positively charged.
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molecules of glass are different from molecules of wood true or false
H3C-CH2-OH
What is the name of this
Answer:
H3C is the chemical name for the methyl group, and it can also be written as CH3
CH2 is a carbene
OH is hydroxide
empirical formula for H2Cl2O6
Answer:
HClO₃
Explanation:
Empirical formula of a chemical compound is defined as the simplest ratio of atoms presents in the compound (In whole numbers).
For the H₂Cl₂O₆ the empirical formula could be obtained dividing in 2 the formula. That is:
HClO₃ → This is the simplest ratio of atoms presents in the compound, that is, the empirical formula
In a compound with molecular formula X2Y3, the valencies of Y and X are
Answer: In a compound with molecular formula [tex]X_2Y_3[/tex] ,the valency of Y and X are 2 and 3 respectively.
Explanation:
For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
The given compound is [tex]X_2Y_3[/tex] where X and Y combine and their oxidation states or valencies are exchanged and written in simplest whole number ratios. Thus the oxidation state or valency of X is 3 and that of Y is 2.
The valency of X is 3 and the valency of Y is 2.
The valency is more simply defined as the combining power of an element. We can see the valency of an element from the subscript of the other atom in the compound. This will now serve as our guide in decoding the valencies of X and Y.
Valency of X - 3Valency of Y - 2Hence, the valency of X is 3 and the valency of Y is 2.
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If you can help answer the question if you can't then don't
a candle burning can be considered both chemical and physical change explain how is that possible ????
Answer:
Yes its both a physical and chemical change heres why.
When heated , the wax melts to form a liquid wax . The liquid wax then becomes a solid wax upon cooling ( Physical change )
When the candle is lit, the wax near the tip of the candle will melt . The wick then absorbs the liquid wax . The liquid wax then vapourizes due to the heat emitting from the flame . The wax vapour then burns to give off a black substance ( what we will to as CO₂ , soot ) , heat and water vapour
(Chemical change )
Brainliest ? Hope I answered your question
A sample of 0.3220 g of an ionic compound containing the iodide ion (I-) is dissolved in water and treated with an excess of AgHCO3. If the mass of the AgI precipitate that forms is 0.235 g, what is the percent by mass of I in the original compound? The molar mass of AgI is 234.8 g.
Answer:
39.44 %
Explanation:
Step 1: Write the balanced equation
I⁻(aq) + AgHCO₃(aq) = AgI(s) + HCO₃⁻(aq)
Step 2: Calculate the moles corresponding to 0.235 g of AgI
The molar mass of AgI is 234.8 g/mol.
[tex]0.235g \times \frac{1mol}{234.8g} = 1.001 \times 10^{-3} mol[/tex]
Step 3: Calculate the moles of I⁻ that form 1.001 × 10⁻³ mol of AgI
The molar ratio of I⁻ to AgI is 1:1. The reacting moles of I⁻ are 1/1 × 1.001 × 10⁻³ mol = 1.001 × 10⁻³ mol
Step 4: Calculate the mass corresponding to 1.001 × 10⁻³ mol of I⁻
The molar mass of I⁻ is 126.90 g/mol.
[tex]1.001 \times 10^{-3} mol \times \frac{126.90g}{mol} = 0.1270 g[/tex]
Step 5: Calculate the percent by mass of I⁻ in the original compound
[tex]\frac{0.1270g}{0.3220g} \times 100 \% = 39.44 \%[/tex]
How is charge balanced in an oxidation-reduction reaction?
Answer:
Charge is balanced in oxidation half-reactions by adding electrons as products; in reduction half-reactions, charge is balanced by adding electrons as reactants.
Hope it helps :] !!!!!!!!!
According to one acid base theory a base is an 1, h2 acceptor 2, h2 donor 3, h+ acceptor 4,h+ donor
Answer:
3, H⁺ acceptor
Explanation:
Let's consider Bronsted-Lowry acid-base theory.
According to this theory, an acid is a substance that donates H⁺ ions. For example, HCl is an acid.
HCl + H₂O = Cl⁻ + H₃O⁺
Cl⁻ is the conjugate base of HCl.
According to this theory, a base is a substance that accepts H⁺ ions. For example, NH₃ is a base.
NH₃ + H₂O = NH₄⁺ + OH⁻
NH₄⁺ is the conjugate acid of NH₃.
According to one acid-base theory, a base is an H+ acceptor.
What is the acid-base theory?The acid-base theory, also called the Brønsted-Lowry theory, is a theory developed by Johannes N. Brønsted and Thomas M. Lowry.
The acid-base theory states that an acid is a proton (H+) donor, whereas a base can be considered as an H+ acceptor.According to Brønsted-Lowry's theory, H2O may act as a base because this molecule acts as a proton (H+) acceptor.In conclusion, according to one acid-base theory, a base is an H+ acceptor.
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How many moles of water form when one mole of NH3 reacts according to this reaction 4 NH3+ 5 O2= 4NO+ 6 H20
moles ratio of NH3 to H2O is 4:6
if 4=6
1. ?
1 * 6 /4 = 1.5
1.5 moles of water
What happens when a primary structure forms a secondary structure
Answer:
The oxygen atoms of the carbonyl groups and the hydrogen atoms attached to the nitrogen atoms form α-helices or β-pleated sheets. The order of the amino acids provides the R groups that interact to determine the tertiary structure
Explanation:
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The density of magnesium is 1.7 g/cm3, and the density of iron is 7.9 g/cm3. Consider a block of iron with a mass of 819 g. What is the mass of a block of magnesium that has the same volume as the block of iron?
Answer:
mass of Mg=0.016g
Explanation:
P(Mg)=1.7g/cm³
P(Fe)=7.9g/cm³
m(Fe)=819g
P(Fe)=m(Fe)/v(Fe)
7.9=819/v(Fe)
v(Fe)=0.0096cm³
since v(Mg)=v(Fe)
=0.0096cm³
P(Mg)=m(Mg) /v(Mg)
1.7=m(Mg)/0.0096
m(Mg) = 0.016g
The mass of the Mg block has been found to be 176.24 grams.
The density can be defined as the mass per unit volume. The density can be expressed as:
Density = [tex]\rm \dfrac{Mass}{Volume}[/tex]
The volume of the object will be:
Volume = [tex]\rm \dfrac{Mass}{Density}[/tex]
The density of Mg block = 1.7 g/[tex]\rm cm^3[/tex]
The density of Fe block = 7.9 g/[tex]\rm cm^3[/tex].
Since the volume of both blocks has been the same.
[tex]\rm \dfrac{Mass\;of\;Mg\;block}{Density\;of\;Mg\;block}\;=\;\dfrac{Mass\;of\;Fe\;block}{Density\;of\;Fe\;block}[/tex]
The given mass of Fe block = 819 g.
Substitute the values:
[tex]\rm \dfrac{Mass\;of\;Mg\;block}{1.7\;g/cm^3}\;=\;\dfrac{819\;g}{7.9\;g/cm^3}[/tex]
Mass of Mg block = 176.24 g.
The mass of the Mg block has been found to be 176.24 grams.
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What type of reaction would come from reactants Cu and O
Answer:
Synthesis
Explanation:
Because the reactants aren't compounds, it has to be a synthesis reaction, in which Cu and O combine to make copper oxide.
Answer:
Synthesis
Explanation:
d
Which option correctly explains a metallic bond
Answer:
The chemical bond between atoms in metallic elements
Explanation:
Metallic bond is a bond that exist between metallic elements. It does not occur between metals and non metals.
Just need to know the one with the Hexagon
Answer:2,4-dichlorohexane
Explanation:
Hope it helps
over
In order for an object to be buoyant, there must be a difference in
the area of the object.
A. force of gravity
B. density
C. fluid pressure
D. mass
Answer:
fluid pressure
Explanation:
a p e x
How many grams of NO are required to produce 145 g of N2 in the following reaction?
4NH3(g) + 6NO(g) → 5N2(g) + 6H2O(l)
a. 155 g
b. 186 g
c. 125 g
d. 145 g
e. 129 g
Answer:
b. 186 g
Explanation:
Step 1: Write the balanced equation.
4 NH₃(g) + 6 NO(g) → 5 N₂(g) + 6 H₂O(l)
Step 2: Calculate the moles corresponding to 145 g of N₂
The molar mass of nitrogen is 28.01 g/mol.
[tex]145g \times \frac{1mol}{28.01 g} =5.18 mol[/tex]
Step 3: Calculate the moles of NO required to produce 5.18 moles of N₂
The molar ratio of NO to N₂ is 6:5.
[tex]5.18molN_2 \times \frac{6molNO}{5molN_2} = 6.22molNO[/tex]
Step 4: Calculate the mass corresponding to 6.22 moles of NO
The molar mass of NO is 30.01 g/mol.
[tex]6.22mol \times \frac{30.01g}{mol} =186 g[/tex]
The mass of NO required to produce 145 g of N₂ is 186 g.
The correct answer to the question is Option B. 186 g
We'll begin by calculating the mass of NO that reacted and the mass of N₂ produced from the balanced equation.
4NH₃ + 6NO —> 5N₂ + 6H₂O
Molar mass of NO = 14 + 16 = 30 g/mol
Mass of NO from the balanced equation = 6 × 30 = 180 g
Molar mass of N₂ = 14 × 2 = 28 g/mol
Mass of N₂ from the balanced equation = 5 × 28 = 140 g
From the balanced equation above,
140 g of N₂ were produce by 180 g of NO
Finally, we shall determine the mass of NO required to produce 145 g of N₂
From the balanced equation above,
140 g of N₂ were produce by 180 g of NO
Therefore,
145 g of N₂ will be produce by = (145 × 180) / 140 = 186 g of NO
Thus, 186 g of NO is required for the reaction.
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When 161.0 mL of water at 26.0°C is mixed with 41.0 mL of water at 85.0°C, what is the final temperature
Answer: The final temperature is [tex]38.0^0C[/tex]
Explanation:
The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.
[tex]heat_{released}=heat_{absorbed}[/tex]
[tex]Q=m\times c\times \Delta T=m\times c\times (T_{final}-T_{initial})[/tex]
[tex]-[m_1\times c_1\times (T_{final}-T_1)]=[m_2\times c_2\times (T_{final}-T_2)][/tex]
[tex]-[m_1\times (T_{final}-T_1)]=[m_2\times (T_{final}-T_2)][/tex] (as [tex]c_1=c_2[/tex])
Q = heat absorbed or released
[tex]m_1[/tex] = mass of water at [tex]85.0^0C[/tex] = [tex]volume\times density=41.0ml\times 1g/ml=41.0g[/tex]
[tex]m_2[/tex] = mass of water at [tex]26.0^0C[/tex] = [tex]volume\times density=161.0ml\times 1g/ml=161.0g[/tex]
[tex]T_{final}[/tex] = final temperature = ?
[tex]T_1[/tex] = temperature of 41.0 ml of water = [tex]85.0^0C[/tex]
[tex]T_2[/tex] = temperature of 161.0 ml of water = [tex]26.0^0C[/tex]
Now put all the given values, we get
[tex]-[41.0\times (T_f-85.0)^0C]=161.0\times (T_f-26.0)^0C[/tex]
[tex]T_f=38.0^0C[/tex]
Thus the final temperature is [tex]38.0^0C[/tex]
An equilibrium mixture of the three gases in a 7.40 L container at 535 K contains 0.313 M PCl5, 0.119 M PCl3 and 0.119 M Cl2. What will be the concentrations of the three gases once equilibrium has been reestablished, if the volume of the container is increased to 16.6 L?
Answer:
PCl₅: 0.1192M
PCl₃: 0.0734M
Cl₂: 0.0734M
Explanation:
Based on the reaction:
PCl₅ ⇄ PCl₃ + Cl₂
K of reaction is defined as:
K = [PCl₃] [Cl₂] / [PCl₅]
Replacing with concentrations of gases in equilibrium:
K = [0.119] [0.119] / [0.313]
K = 0.0452
Moles of each gas is:
PCl₅: 7.40L × (0.313mol / L) = 2.3162 moles
PCl₃: 7.40L × (0.119mol / L) = 0.8806 moles
Cl₂: 7.40L × (0.119mol / L) = 0.8806 moles
When the volume of the container is increased the system will produce more moles, (That is, produce more products) in order to keep constant the pressure of the container -Le Chatelier's principle-. In equilibrium, molarity of each gas is:
PCl₅: 2.3162 moles - x / 16.6L
PCl₃: 0.8806 moles + x / 16.6L
Cl₂: 0.8806 moles + x / 16.6L
Where X is reaction coordinate.
Replacing in K formula:
0.0452 = [0.05305 + X/16.6] [0.05305 + X/16.6] / [0.13953 - X/16.6]
6.3068x10⁻³ - 2.723x10⁻³ X = 0.0028143 + 0.00639157 X + 0.00362897 X²
0 = -0.0034925 + 0.00911457X + 0.00362897 X²
Solving for X:
X = -2.8 → False answer. There is no negative concentrations
X = 0.3378 moles
Replacing:
PCl₅: 2.3162 moles - 0.3378 / 16.6L = 0.1192M
PCl₃: 0.8806 moles + 0.3378 / 16.6L = 0.0734M
Cl₂: 0.8806 moles + 0.3378 / 16.6L = 0.0734M
Beeing these concentrations the concentrations in equilibrium of the three gases
