Answers
Answer:
The total change in energy is -183 kJ/mol, and the reaction is exothermic.
Explanation:
1st) To calculate the total change in bond energy, it is necessary to calculate the energy of the broken bonds (in the reactants side) and the energy of the formed bonds (in the products side):
• Energy of broken bonds:
H-H: 1 x 432 = 432 kJ/mol
Cl-Cl: 1 x 239 = 239 kJ/mol
Total energy of broken bonds = 432 kJ/mol + 239 kJ/mol
Total energy of broken bonds = 671 kJ/mol
• Energy of formed bonds:
H-Cl: 2 x 427 = 854 kJ/mol
Total energy of formed bonds = 854 kJ/mol
2nd) Now to calculate the total change in bond energy, we have to subtract the Total energy of broken bonds minus the total energy of the formed bonds:
Total change in energy = Total energy of broken bonds - Total energy of formed bonds
Total change in energy = 671 kJ/mol - 854 kJ/mol
Total change in energy = -183 kJ/mol
Finally, the total change in energy is -183 kJ/mol, and the negative sign means that the reaction is exothermic, because
Answer: The total change of the energy is -183 kJ/mol
Explanation:
The way I would calculate the total change in the bond energy in the following steps:
- To calculate the whole change in the bond energy. By calculating the energies of the broken bonds and then the energy of the formed bonds.
-132 kJ/mol + 239 kJ/mol = a total of 671 kJ/mol broken bonds.
-H-CI: 2 x 427 = 854 kJ/mol
-Second to calculate the change in the bond energy we now need to subtract the total energy of the broken bond from the total energy of the formed bonds.
-Change in energy = 671 kJ/mol - 854 kJ.mol
-The total change of the energy is -183 kJ/
- Having the negative, therefore, means the reaction is exothermic.
Related Questions
Add 43.8lbs and 56.8923lbs. What is the answer in the correct significant figures?
Answers
The answer in correct significant figures of the addition of the two numbers mentioned is 100.70.
What are significant figures?Significant figures are used for establishment of a number which is presented in the form of digits. These digits give a meaningful representation to the numbers.
The significant figures are the significant digits which convey the meaning according to the accuracy. These provide precision to the numbers and hence are called as significant numbers.There are rules for counting significant figures which are as follows:
1)All non-zero digits are significant .
2)All zeroes which occur between non-zero digits are significant.
3)All zeroes to the left and right of a non-zero digit are not significant.
4) All zeroes on right of decimal are significant if a non-zero number follows them.
5)All zeroes on right side of non-zero digit are significant.
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how many molecules are there in 2.13 moles of sodium bromide
Answers
Answer:
121 I think not sure tbh......
Which of the following statements is one of the postulates in Dalton’s atomic theory?1. Atoms of different elements can physically mix together.2. Atoms of one element can be changed into atoms of another element through a chemical reaction.3. All compounds are composed of multiple elements combined together.4. Atoms of one element cannot be changed into another element through a chemical reaction.
Answers
Answer:
All atoms of a specific element are identical in mass, size, and other properties. However, atoms of different element exhibit different properties and vary in mass and size. Atoms can neither be created nor destroyed. Furthermore, atoms cannot be divided into smaller particles.
**NEED USEFUL ANSWER ASAP**
How do the masses of the hottest main sequence stars compare to the masses of the coolest main sequence stars?
Answers
Answer:
the more hotter the star, the more brightly it burns
Explanation:
someone just deleted my answer ugh sorry....ill write it again
so, te main sequence is a sequence in mass (and not a sequence in time).
The most massive stars are located at the the top left (since they are the brightest and hottest/bluest). The lowest mass stars are are located at the bottom left ( since they dimmer and cooler/redder).
Following the main sequence from the top left to the bottom right is thus a sequence from high to low mass.
16.Solid carbon dioxide (dry ice) passes directly into the gaseous state. The name for this process is...Select one:a. boiling.b. evaporation.c. melting.d. sublimation.
Answers
Answer:
[tex]D[/tex]Explanation:
Here, we want to select the correct option
We evaluate each of the options as follows:
a) Boiling
It is a state that occurs when the vapor pressure equals atmospheric pressure for liquid substances
b) Evaporation
Evaporation occurs when liquid substances change directly into the gaseous state
c) Melting is the change from the solid state to the liquid state
d) Sublimation is the direct change of a substance from the solid to the vapor state. We can see this in iodine and naphthalene
How many ions in 800.0mL of 0.10M sucrose
Answers
M = mol/L
To solve for the number of atoms in a certain amount of moles, we must multiply the number of moles by Avogadro's number ([tex]N_A[/tex]): [tex]6.02*10^{23}[/tex], and multiply the product by the number of atoms in the compound.
Solving the QuestionWe're given:
Sucrose = [tex]C_{12}H_{22}O_{11}[/tex]800.0 mL0.10 MFirst, we must find the number of moles. We can do this by first converting 800.0 mL to L and multiplying it by 0.10 M.
800.0 mL ÷ 1000 = 0.8 L
⇒ Now, multiply 0.8 L by 0.10 M:
0.8 L × 0.10 M = 0.08 mol
Now, we must find the number of molecules in this sample. Multiply 0.08 mol by Avogadro's number:
[tex]0.08*6.02*10^{23}\\=0.4816*10^{23}\\=4.816*10^{22}[/tex]
Finally, to find the number of atoms in the sample, multiply the number of molecules by the number of atoms in the compound.
We can begin by finding the number of atoms in sucrose:
[tex]C_{12}H_{22}O_{11}[/tex]
12 + 22 + 11 = 45 atoms
⇒ Multiply 45 atoms by [tex]4.816*10^{22}[/tex] mol:
[tex]45*4.816*10^{22}\\=216.72*10^{22}\\=2.1672*10^{24}[/tex]
Convert to the correct number of significant figures (2):
[tex]=2.17*10^{24}[/tex]
Answer[tex]2.17*10^{24}[/tex] atoms
9) A base can release hydroxide ions in a solution. In this following reaction, which
one is the base?
NaOH(s) + H20(1) - Na+(aq) + OH-(ag)
Answers
Answer:
NaOH
Explanation:
Sodium hydroxide is a proton acceptor. Metal hydroxides are almost always bases. H₂O is water and is neutral. Sodium is a positively charged metallic ion. Hydroxide is a negatively charged ion.
Predict the shape of the molecule around the indicated atom.
Answers
Answer:
Linear (180 degrees)
Explanation:
Whenever you have a triple bond between two atoms, their shape is linear. This is because the density of the triple bond between them is heavy, causing the other things attached to the atom to be as far away as possible, creating a linear structure.
CanvasX &Question 16Consider the reaction: 4Na(s) + O2(8) → 2Na2O(s)
Answers
ANSWER
The mass of Na2O in grams is 123.49 grams
EXPLANATION:
Given information
The mass of sodium is 91 grams
The mass of oxygen is 34.0 grams
To find the amount of Na2O produced, follow the steps below
Step 1: Write the balanced equation of the reaction
[tex]\text{ 4Na}_{(s)}\text{ + O}_{2(g)}\rightarrow\text{ 2Na}_2O_{(S)}[/tex]Step 2: Find the number of moles of sodium and oxygen using the formula below
[tex]\text{ Mole = }\frac{\text{ mass}}{molar\text{ mass}}[/tex]Recall, that the molar mass of Na is 22.989 g/mol, and the molar mass of oxygen atom is 32 g/mol
For Na
[tex]\begin{gathered} \text{ Mole = }\frac{mass}{molar\text{ mass}} \\ \text{ Mole = }\frac{91.6}{22.989} \\ \text{ Mole = 3.985 moles} \end{gathered}[/tex]For O2
[tex]\begin{gathered} \text{ Mole = }\frac{mass}{molar\text{ mass}} \\ \text{ } \\ \text{ Mole = }\frac{34}{32} \\ \text{ Mole = 1.0625 moles} \end{gathered}[/tex]Step 3: Find the limiting reactant of the reaction
The limiting reactant is the reactant that has the least number of moles after dividing it by the coefficient of the reactant
From the reaction above, you will see that 4 moles of sodium react with one mole of oxygen to give 2 moles of sodium oxide.
For Na
[tex]\begin{gathered} \text{ Na = }\frac{\text{ number of moles}}{\text{ coefficient}} \\ \text{ Na = }\frac{3.985}{4} \\ \text{ Na = 0.99625 mole/wt} \\ \\ \text{ For O}_2 \\ \text{ O}_2\text{ = }\frac{1.0625}{1} \\ \text{ O}_2\text{ = 1.0625 moles/wt} \end{gathered}[/tex]From the above calculations, you will see that Na has the least number of moles, hence, Na is the limiting reactant
Step 4: Find the number of moles of Na2O
The Na2O can be determined using a stoichiometric ratio
Let x represents the number of moles
[tex]\begin{gathered} \text{ 4 moles of Na }\rightarrow\text{ 2 moles of Na}_2O \\ 3.985\text{ moles of Na }\rightarrow\text{ x moles of Na}_2O \\ \text{ cross multiply} \\ \text{ 4 moles of Na }\times\text{ x moles of Na}_2O\text{ = 2 moles of Na}_2O\times3.985\text{ moles of Na} \\ \text{ x moles of Na}_2O\text{ = }\frac{2\cancel{moles\text{ of Na}_2}O\times3.985\cancel{moles\text{ of Na}}}{4\cancel{moles\text{ of Na}}} \\ \text{ x moles of Na}_2O\text{ = }\frac{2\times\text{ 3.985}}{4} \\ \text{ X moles of Na}_2O\text{ = 1.9925 moles} \end{gathered}[/tex]Hence, the number of moles of Na2O is 1.9925 moles
Step 5: Find the mass of Na2O
[tex]\begin{gathered} \text{ Mole = }\frac{\text{ mass}}{\text{ molar mass}} \\ \end{gathered}[/tex]Recall, that the molar mass of Na2O is 61.9789 g/mol
[tex]\begin{gathered} \text{ 1.9925 = }\frac{\text{ mass}}{61.978} \\ \text{ Cross multiply} \\ \text{ Mass = 1.9925}\times61.978 \\ \text{ Mass = 123.49 grams} \end{gathered}[/tex]Hence, the mass of Na2O in grams is 123.49 grams
Which is a property of all acids?OA. They increase the OH concentration in solution.OB. They increase the H* concentration in solution.OC. They contain OH ions.OD. They contain H3O+ ions.
Answers
Answer
B - They increase the H+ concentration in solution.
Explanation
All acids contain H+ for example, HCl contributes H+ ions into the solution, which decreases the pH of the solution. for example, a base, NaOH increases the concentration of OH⁻ ions and decreases the concentration of H⁺ ions. Therefore all acids increase the H+ concentration in solution.
What is the final concentration when 288mL of water is added to 239mL of a 0.274M solution?
Answers
Answer:
0.124 M.
Explanation:
What is given?
Volume 1 (V1) = 239 mL,
Concentration 1 (C1) = 0.274 M,
Volume 2 (V2) = 239 mL + 288 mL = 527 mL.
What do we need? Concentration 2 (C2).
Step-by-step solution:
To solve this problem, we have to use the following formula:
[tex]C_1V_1=C_2V_2.[/tex]Where the initial concentration (C) and volume (V) are represented with subindex 1, and the final concentration and volume are represented with subindex 2.
The problem is telling us that we are adding 288 mL of water to 239 mL, so the final volume is the sum of these two volumes, i.e., 527 mL.
As we want to find the final concentration, C2, we just have to solve for this unknown value and replace the values that we have, like this:
[tex]\begin{gathered} C_2=\frac{C_1V_1}{V_2}, \\ \\ C_2=\frac{0.274\text{ M}\cdot239\text{ mL}}{527\text{ mL}}, \\ \\ C_2=0.124\text{ M.} \end{gathered}[/tex]The answer would be that the final concentration of the solution is 0.124 M.
If the mercury in a barometer raises 22.8 centimeters due to a change in ambient pressure, what is the corresponding change in pressure in atm?
Answers
If the mercury in a barometer raises 22.8 centimeters due to a change in ambient pressure, then the corresponding change in pressure would be 0.3 atm.
What is pressure?The total applied force per unit of area is known as the pressure.
The pressure depends both on externally applied force as well the area on which it is applied
As given in the problem If the mercury in a barometer raises 22.8 centimeters due to a change in ambient pressure, then we have to find out the corresponding change in pressure in atm,
760 mm of Hg = 1 atm
76 cm of Hg = 1 atm
1 cm of Hg = 1 / 76 atm
22.8 cm of Hg = 22.8 / 76 atm
= 0.3 atm
Thus , the corresponding change in pressure in atm would be 0.3 atm .
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How much heat is released when 245 g of steam cools from 106.0°C to -4.5°C
Answers
ANSWER
The amount of heat released is -54, 957.175J
EXPLANATION
Given that;
[tex]\begin{gathered} \text{ The mass of the steam is 245g} \\ \text{ The final temperature of the steam is -4.5}\degree C \\ \text{ The initial temperature of the steam is 106.0}\degree C \end{gathered}[/tex]To find the amount of energy released, then apply the below formula
[tex]\text{ q = mc \lparen}\theta2\text{ - }\theta1)[/tex]Recall, that the specific heat capacity of steam (c) is 2.03 J/g degrees Celcius
[tex]\begin{gathered} \text{ q = 245 }\times\text{ 2.03 \lparen-4.5 - 106\rparen} \\ \text{ q = 245 }\times\text{ 2.03 \lparen -110.5\rparen} \\ \text{ q = -54,957.175J} \end{gathered}[/tex]Therefore, the amount of heat released is -54, 957.175J
A chemical reaction has the equation 2AgNO3 (aq) + Zn (s) → 2Ag (s) + Zn(NO3)2 (aq). What type of reaction occurs between AgNO3 and Zn?Question 17 options:A) Single displacementB) DecompositionC) SynthesisD) Double displacement
Answers
Combination (also called synthesis): Where two elements or one compound and one element will bond and form a new compound as a product, the representation for this reaction is:
A + B -> AB
Decomposition: The opposite from Combination, now one compound will decompose and form 2 new elements or compounds as the product:
AB -> A + B
Single Replacement: One element will take the place of another element in already existing compound:
A + BC -> AB + C
Double Replacement: Now we have two compounds switching elements and forming two new compounds:
AB + CD -> AC + BD
Combustion: Reactions that involve oxygen as reactant and we have CO2 and H2O as products:
X + O2 -> CO2 + H2O
According to the explanation, what we have in this reaction is a Single Displacement reaction, letter A
The quantatum mechanical model of an atom uses atomic orbitals to describe what
Answers
C3H8 + 4 Cl2 --> C3H4Cl3 + 4 HCL
A 6 mol sample of C3H8 and a 20 mol sample of Cl2 are placed in a previously evacuated vessel, where they react according to the equation above. After one of the reactants has been totally consumed, how many moles of HCl have been produced?
A. 4 mol
B, 8 mol
C. 20 mol
D. 24 mol
How would I solve this?
Answers
After one of the reactants has been totally consumed, the moles of HCl that have been produced is 20 moles.
What is the mole ratio of the reactants in the reaction?The mole ratio of the reactants in the reaction is given below:
Equation of the reaction:
C₃H₈ + 4 Cl₂ --> C₃H₄Cl₄ + 4 HCl
The mole ratio of C₃H₈ and Cl₂ is 1 : 4
The mole ratio of the reactants, C₃H₈ and Cl₂ present is 6 : 20
mole ratio of the reactants, C₃H₈ and Cl₂ present is 3 : 10
Hence the limiting reactant is Cl₂
Moles of HCl to Cl₂ is 1 : 1.
Hence, the moles of HCl produced will be 20 moles
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ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through _____.
Answers
Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through gap junctions.
What is cytoplasm?Cytoplasm is the gelatinous liquid that fills the inside of a cell.
The cytoplasm is composed of water, salts, and various organic molecules. Some intracellular organelles, such the nucleus and mitochondria, are enclosed by membranes that separate them from the cytoplasm.
The cytoplasm has the following functions :
The cytoplasm functions to support and suspend organelles and cellular molecules.The cytoplasm also has many cellular processes which occur in them such as protein synthesis, the first stage of cellular respiration (known as glycolysis), mitosis, and meiosis.Learn more about the cytoplasm at: https://brainly.com/question/174023
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Limestone is a sedimentary rock composed largely of the mineral calcite, (calcium carbonate) CaCO3. To test the purity of the calcium carbonate, a sample of the mineral is reacted with hydrochloric acid to produce calcium chloride, carbon dioxide and water If a 15.70 g sample of calcite is reacted with excess hydrochloric acid and 16.89 g of calcium chloride are produced, what is the percent by mass of the calcium carbonate in the limestone? A) 69.4% B)93.0 % C) 96.94% D)98,22 %
Answers
Answer:
[tex]C\text{ : 96.94 \%}[/tex]Explanation:
Here, we want to get the percentage by mass of calcium carbonate in the limestone
We start by writing an equation of chemical reaction
The reaction involves calcium carbonate reacting with hydrochloric acid to give calcium chloride, carbon dioxide and water
We have the equation as follows:
[tex]\text{CaCO}_{3(s)\text{ }}+2HCl_{(aq)}\rightarrow CaCl_{2(aq)\text{ }}+CO_{2(g)\text{ }}+H_2O_{(l)}[/tex]Now, let us work with the extra information
16.89 g of calcium chloride are produced
Let us get the number of moles of calcium chloride produced
We can get that by dividing the mass by the molar mass of calcium chloride
The molar mass of calcium chloride is 111 g/mol
So, the number of moles will be:
[tex]\frac{16.89}{111}\text{ = 0.1522 mole}[/tex]From the equation,
1 mole of calcite gave 1 mole of calcium chloride, then 0.1522 mole of calcium chloride was produced by 0.1522 mole of calcite
To get the mass of calcite that produced this, we have to multipply the number of moles by the molar mass of calcite
The molar mass of calcite is 100 g/mol
That means the mass of calcite that produced the calcium chloride will be:
[tex]0.1522\text{ }\times\text{ 100 = 15.22 g}[/tex]What this mean is that 15.22 g of calcite produced the given mass of calcium chloride
The percentage by mass of calcite in the limestone will be:
[tex]\frac{15.22}{15.70}\times\text{ 100\% = 96.94 \%}[/tex]Initially a sample of nitrogen gas is found in a pressure of 4.62 atm under the temperature of 27.0°C
Answers
The change in the temperature of the gas, given that the volume is held constant is 63 °C
How to determine the change in temperatureLet's begin by obtaining the new temperature of the gas. This can be obtained as follow:
Initial pressure (P₁) = 4.62 atm Initial temperature (T₁) = 27 °C = 27 + 273 = 300 KNew pressure (P₂) = 5.59 atm New temperature (T₂) =?P₁ / T₁ = P₂ / T₂
4.62 / 300 = 5.59 / T₂
Cross multiply
4.62 × T₂ = 300 × 5.59
Divide both side by 4.62
T₂ = (300 × 5.59) / 4.62
T₂ = 363 K
Subtract 273 to obtain answer in °C
T₂ = 363 – 273 K
T₂ = 90 °C
Finally, we shall determine the change in the temperature. This is illustrated below:
Initial temperature (T₁) = 27 °CNewl temperature (T₂) = 90 °CChange in temperature (ΔT) =?ΔT = T₂ – T₁
ΔT = 90 – 27
ΔT = 63 °C
The, the change in the temperature is 63 °C
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Complete question:
See attactched photo
According to Bronsted-Lowry Theory, a base is.....Group of answer choicesa H+ donora H+ acceptora OH- donorwater
Answers
answer and explanation
a bronsted-lowry basic is a H+ donor
A mixture of nitrogen and hydrogen gas is compressed from a volume of 90.0L to a volume of 89.0L, while the pressure is held constant at 44.0atm. Calculate the work done on the gas mixture. Round your answer to 2 significant digits, and be sure it has the correct sign (positive or negative).
Answers
The PV work formula is:
w = -Pexternal * ΔV
w = -44.0 atm * (89.0 - 90.0)
w = -44.0 atm * -1 L
w = 44.0 L atm
For each L atm, we will have 101.325 Joules, therefore
44.0 L atm * 101.325 J
w = 4458.3 J or 4.4 kJ
A balloon has a volume of 1785 mL at 25°C, if the volume of balloon changes to 1.25 L, what is the new temperature in degree Celcius atconstant pressure and amount?
Answers
We work here with Charles' Law. The equation used here is:
V1/T1 = V2/T2 (1)
(pressure and amount constant)
V is for volume and T for temperature
V1 = 1785 mL
1 L = 1000 mL ==> V1 = 1.785 L
T1 = 25 °C = 25 °C + 273 = 298 K
V2 = 1.25 L
T2 = unknown
From (1) we clear T2:
T2 = V2 x T1/V1 = 1.25 L x 298 K/1.785 L = 209 K approx.
T2 = 209 K - 273 = -64 °C
Answer: T2 = -64 °C
What volume of Cl2 gas, measured at 688 torr and 36 °C, is required to form 22 g of NaCl?Express your answer using two significant figures.
Answers
ANSWER
Volume of the gas 5.3L
EXPLANATION;
Given that
The pressure of the chlorine gas is 688 torr
The temperature of the chlorine gas is 36 degrees Celcius
The mass of NaCl is 22 grams
Follow the steps below to find the volume of chlorine gas
Step 1; Write a balanced equation for the reaction
[tex]\text{ 2Na + Cl}_2\text{ }\rightarrow\text{ 2NaCl}[/tex]In the above reaction, 2 moles of Na react with 1 mole of chlorine to form 2 moles of NaCl
Step 2; Find the number of moles of NaCl using the below formula
[tex]\text{ mole = }\frac{\text{ mass}}{\text{ molar mass}}[/tex]Recall, that the molar mass of NaCl is 58.44 g/mol
[tex]\begin{gathered} \text{ mole = }\frac{22}{\text{ 58.44}} \\ \text{ moles = 0.376 mole} \end{gathered}[/tex]Step 3; Find the number of moles of Cl2 using a stoichiometry ratio
Let x represents the number of moles of Cl2
[tex]\begin{gathered} 1\text{ mole Cl}_2\text{ }\rightarrow\text{ 2 moles NaCl} \\ \text{ x moles Cl}_2\rightarrow\text{ 0.376 moles NaCl} \\ \text{ cross multiply} \\ \text{ x moles Cl}_2\text{ }\times2\text{ moles NaCl }=\text{ 1 mole Cl}_2\text{ }\times\text{ 0.376 mole NaCl} \\ \text{ Isolate x} \\ \text{ x = }\frac{\text{ 1 mole Cl}_2\times0.376moles\cancel{NaCl}}{2moles\cancel{NaCl}} \\ \\ \text{ x = }\frac{1\text{ }\times\text{ 0.376}}{2} \\ x\text{ = }\frac{0.376}{2} \\ \text{ x = 0.188 mol} \end{gathered}[/tex]The number of moles of Cl2 is 0.188 mol
Step 4; Find the volume of the gas using the ideal gas equation
[tex]\text{ PV = nRT}[/tex]Convert the temperature to degree kelvin
[tex]\begin{gathered} \text{ t = 36}\degree C \\ \text{ T = 36 + 273.15} \\ \text{ T = 309.15 K} \end{gathered}[/tex]Step 5; Find the volume of the gas
[tex]\begin{gathered} \text{ PV = nRT} \\ \text{ Recall, that R = 62.363 L. torr mol}^{-1}K^{-1} \\ \text{ 688}\times\text{ V =}^{\text{ }}0.188\text{ x 62.636 }\times\text{ 309.15} \\ \text{ 688 V = 3624. 500} \\ V\text{ = }\frac{\text{ 3645, 500}}{688} \\ \text{ v = 5.3 L} \end{gathered}[/tex]Therefore, volume of the gas 5.3L
how did democritus model change throughout history write a paragraph using other theories about atoms.
Answers
Democritus proposed the idea that atoms were unique to the substance they were found .
How has the atomic model evolved through time?Model of Bohr (1913)
Niels Bohr made Rutherford's model better. He demonstrated, using mathematical concepts, that electrons reside in energy levels or shells surrounding the nucleus. Due to the discovery of subatomic particles, the Dalton model has evolved over time.
The importance of the atomic theoryAstonishing scientific advancements in fields like contemporary chemistry and nuclear energy resulted from the finding that all matter is composed of microscopic particles, which was made possible by the atomic theory.
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need help with this pleaseeeeeeeeeeeeeeWhat trends do you see in the organisms of the ecosystem if youdecrease sunlight A. Increase in energy storage moleculesB. Decrease in H2OC. Decrease in energy storage moleculesD. Increase in CO2
Answers
Answer:
Explanations:
Answer:
Explanations:
How many moles of sulfur dioxide in 85 grams sulfur dioxide?
Answers
Answer:
1.33 moles
Explanation:
[tex]n = \frac{mass}{molar \: mass} [/tex]
note Molar Mass according to websearch is 64 066
you could calculate this using the individual elements on a periodic table (sulfur and oxygen) and their masses
[tex]n = \frac{85}{64.066} [/tex]
[tex]n = 1.33[/tex]
How many kilojoules are required to melt 15g of ice at 0 degrees celsius and raise the temperature of the liquid that forms to 85 degrees celsius.
Answers
The amount of heat, in kilojoules, that is required to melt 15 g of ice at 0 degrees Celsius and raise the temperature of the liquid to 85 degrees Celsius is 10.3178 kJ.
Heat changeThe process involves melting of ice at 0 degrees Celsius and then heating the resulting water to a temperature of 85 degrees Celsius.
Solid water is first converted to liquid water without a change in temperature.Liquid water is heated without a change of state to 85 degrees Celsius.Now, let's calculate the heat change of the process:
Heat change (ΔH) = n x heat of fusion) + mcΔt
Where n = number of moles
m = mass = 15 g
c = specific heat capacity of water = 4.81 J/g[tex]^oC[/tex]
heat of fusion = 6010 J/mole
In this case, n = mass/molar mass
= 15/18
= 0.83 moles
ΔH = (0.83 x 6010) + 15 x 4.81 x (85 - 0)
= 10317.8 Joules
But 1000 Joules = 1 kilojoules
Thus, 10317.8 joules = 10.3178 kJ
The kilojoule of heat required to melt the ice and raise the temperature of the resulting water to 85 degrees Celsius is 10.3178 kJ.
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Name the following compoundCH3-CH-CH2-CH3 | Br
Answers
2 brome butane
it has 4 C atoms therefor we know it is a butan-- and the brome is placed in the second carbone so that gives the answer 2 brome butane
A 25.0 mL aliquot was taken from a 500.0 mL sample of tonic water containing an unknown amount of quinine and diluted to a volume of 200.0 mL. At 347.5 nm, the fluorescence intensity of the diluted sample was measured as 73.7 on an arbitrary scale. Under similar conditions, a 25.0 ppm standard quinine solution had a fluorescence intensity of 195 . Calculate the mass of quinine in the original tonic water sample.
Answers
The mass of quinine in the original tonic water sample is 37.8 mg.
What is the concentration of the diluted sample?The concentration of the diluted sample with a fluorescence intensity of 73.7 is calculated using the formula of Lambert-Beer's law as follows:
C₁/C₂ = A₁/A₂
where:
C₁ = 25 ppm or 25 mg/L
C₂ = ?
A₁ = 195
A₂ = 73.7
C₂ = 73.7 * 25 / 195
C₂ = 9.45 mg/L
To concentration of the original sample will be determined from the dilution formula:
C₁V₁ = C₂V₂
where;
C₁ = ?
V₁ = 25. 0 mL
C₂ = 9.45 mg/L
V₂ = 200 mL
C₁ = 9.45 * 200 / 25
C₁ = 75.6 mg/L
The volume of the stock sample was 500 mL or 0.5 L
The mass of quinine = 75.6 mg/L * 0.5 L
mass of quinine = 37.8 mg
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How many moles of ammonium nitrate (NH4NO3) are present in 0.085 L of a 0.23 M ammonium nitrate (NH4NO3) solution?
Answers
Answer:
No. of moles [tex]\approx[/tex] 0.020
Explanation:
To calculate the number of moles of a substance in a solution given its concentration and volume, we use the following formula:
[tex]\boxed{\mathrm{No. \ of \ moles = Concentration \times Volume}}[/tex],
where concentration is in mol/dm³ (or M) and volume is in L.
In the question, we are told that the volume of the solution is 0.085 L and that its concentration is 0.23 M. Substituting these values into the formula above, we get:
No. of moles = 0.23 × 0.085
= 0.01955
[tex]\approx[/tex] 0.020 mol (3 s.f.)
Therefore, there are 0.020 moles of NH₄NO₃ in the solution.
