Answer
% mass of KCl = 25.76%
Explanation
Given:
mass of KCl = 42.5 g
mass of water = 122.5 g
Required: The % mass of KCl
Solution:
Step 1: Calculate the total mass
42.5 g + 122.5 g = 165 g
Step 2: Calculate the % of KCl
%KCl = (42.5/165)*100
%KCl = 25.76%
What kind of energy transfer happens when you hang Christmas lights?
Answer: For example, Christmas lights transform electrical energy into thermal energy and light energy.
Explanation: so it either thermal or light, most likely light.
-8- A student conducted a number of tests on a solid mixture, X. The inferences made are recorded in Table 2. Complete Table 2 by filling in the observations based on the inferences made. TABLE 2: TESTS ON MIXTURE X Test Observation Inferences (a) Distilled water was added to a portion of X and the resulting mixture stirred and filtered. (The residue was set aside for use later.) The filtrate was divided into 3 equal portions and tests (b) to (d) done on separate portions. Clions are present. (b) Dilute nitric acid followed by a few drops of silver nitrate solution was added. Ammonium hydroxide solution was added to the resulting mixture. An oxidizing agent is present. (c) A few drops of potassium iodide solution were added. Iron(III) ions are present. Aqueous sodium hydroxide was added until in excess. Carbonate ions are present. (e) Dilute nitric acid was added to the residue from test (a) and the gas produced passed through lime water. Total 1 •Pet (3 marks) (2 marks) (2 marks) (3 marks)
Answer:
There would be a change in the color of the potassium iodide from yellowish-brown to colorless
Explanation:
Here, we want to test for the presence of oxidizing agent by the use of potassium iodide
Since we already have the inference, we need to state what would be observed
Potassium iodide itself is a reducing agent
Thus, it becomes oxidized
In the process of being oxidized, there would be a color change
The color change observed will be from yellowish-brown to colorless
100 points!
Why rusting is a chemical change?
1-A new reactant is formed
2-A new product is formed
3-There is increased activation energy
4-A new substance is not formed
Answer: 4
Explanation:
How many moles of NaOH are present in 12.0mL of 0.110 M NaOH? Moles: _________
NaOH
M = molarity (mol/L)
[tex]M\text{ = }\frac{mass\text{ of solute}}{\text{molecular mass of solute x volume of solution (L)}}=\frac{moles\text{ of solute}}{\text{volume of solution(L)}}[/tex][tex]M=0.110\text{ }\frac{mol}{L}=\text{ }\frac{moles\text{ of NaOH}}{0.012L}[/tex]12.0 ml = 0.012 L
[tex]\text{moles of NaOH = 0.11 }\frac{mol}{L}x0.012L=1.32x10^{-3\text{ }}moles\text{ of NaOH}[/tex]Answer: moles of NaOH = 1.32x10^-3 moles
[tex]\text{moles NaOH = 1.32x10}^{-3}moles\text{ = 0.00132 moles NaOH}[/tex]How do you calculate mass of a known substance (sodium chloride for example) given its amount in terms of moles? O multiply moles by the molar mass O divide moles by the molar mass O cannot be determined based on the given divide the molar mass by the Avogadro's number
1) List the known and unknown quantities.
Amount of substance: moles
mass: grams
2) Set the equation.
[tex]Molar\text{ }Mass=\frac{Mass\text{ }(grams)}{Amount\text{ }of\text{ }substance\text{ }(moles)}[/tex][tex]Molar\text{ }Mass\ast Amount\text{ }of\text{ }substance\text{ }(moles)=Mass\text{ }(grams)[/tex]If we have the number of moles of a compound, we have to multiply it by the molar mass to find the mass.
Answer: multiply moles by the molar mass.
.
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?
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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One of the waste products produced by kidneys is creatinine. A healthy range ofcreatinine in human blood is between 0.50 mg/dL and 1.1 mg/dL. Elevated levels of thiscompound could indicate a problem with kidney function.The concentration of creatinine in patient’s blood was reported in g/L: 0.0082 g/L.Is this value within the normal range? If it is not, is this concentration low or high?Confirm your answer with your calculations and show all the work.The concentration of creatinine = _____________mg/dL. It is ______________the normal range
The normal range of creatinine in human blood is between 0.50 mg/dL and 1.1 mg/dL. The patient's blood has a concentration of 0.0082 g/L. Let's convert that value into mg/dL.
We kwnot that there are 1000 mg in 1 g. And there are 10 dL in 1 L. We have to use those conversions.
1000 mg = 1 g 10 dL = 1 L
0.0082 g/L = 0.0082 g/L * 1000 mg/g = 8.2 mg/L * 1 L/ (10 dL) = 0.82 mg/dL
0.0082 g/L = 0.82 mg/dL
0.50 mg/dL < 0.82 mg/dL < 1.1 mg/dL
Answer: The concentration of creatinine = 0.82 mg/dL. It is in the normal range.
5. 10.1 grams of hydrogen gas is contained in a volume of 5.00 L at a temperature of 37.5℃. Find the pressure of the gas.
Answer: 2607.31 pa
Explanation:
n = 10.1/2 = 5.05 mol
Now, according to ideal gas equation,
PV = nRT
⇒ P × 5 = 5.05 × 8.314 × (37.5 +273)
⇒P = 2607.31 Pa
35.A substance that affects the speed of a chemical reaction without itself being chemically changed is called a...Select one:a. catalyst.b. product.c. reactant.d. yield.
Answer
A. catalyst
Explanation
Catalyst, in chemistry, any substance that increases the rate of a reaction without itself being consumed.
Choose the effect of acid you think is most important, and justify your choice.
The effect of acid you think is most important because chemical that can donate a hydrogen ion to other molecule
Acid is an that in water solution taste sour and changes blue litmus to red and react to some metal to liberate hydrogen react with bases to form salt and and also promote chemical reaction and the effect of acid is the chemical that can donate hydrogen ion to other molecule and the result in other molecule changing shape and possibly breaking apart
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Follow these steps to write the balanced chemical equation for the reaction between nitric acid and iron (III)hydroxide.1. Start by writing the proper names of the products below (separated by a + sign).Nitric acid +Iron (III) hydroxide I2. Next, write the full, balanced molecular equation with the correct chemical formulas, includingcoefficients.3. Finally, write the net ionic equation for this reaction below, including ionic charges.
If 22.4 mL of 0.25 M sodium hydroxide are required
neutralize 15.0 mL of a hydroiodic acid solution, how
many grams of hydrogen iodide were dissolved in the
solution?
According to the concept of molar concentration,0.715 g of hydrogen iodide are dissolved in the solution.
What is molar concentration?Molar concentration is defined as a measure by which concentration of chemical substances present in a solution are determined. It is defined in particular reference to solute concentration in a solution . Most commonly used unit for molar concentration is moles/liter.
The molar concentration depends on change in volume of the solution which is mainly due to thermal expansion. Molar concentration is calculated by the formula, molar concentration=mass/ molar mass ×1/volume of solution in liters.
In terms of moles, it's formula is given as molar concentration= number of moles /volume of solution in liters.
Using the formula of M₁V₁=M₂V₂ molarity of HI is determined,that is ,M₂=0.25×22.4/15=0.373 M.
For determining the mass is determined by using the formula,mass=0.373×127.911×0.015=0.715 g
Thus, 0.715 g of hydrogen iodide are required for making the solution.
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Two atoms with atomic numbers 12 and 17 would
bond to form an ionic compound
bond to form a covalent compound
bond to form a metallic lattice
not bond with each other
Answer:
bond to form a covalent bond
Explanation:
a covalent bond is formed when two atoms share electron pairs.
A sheet of gold weighing 10.7 g and at a temperature of 19.8°C is placed flat on a sheet of iron weighing 18.7 g and at a temperature of 53.3°C. What is the final temperature of the combined metals? Assume that no heat is lost to the surroundings.
A sheet of gold weighing 10.7 g and at a temperature of 19.8 °C is placed flat on a sheet of iron weighing 18.7 g and at a temperature of 53.3 °C. the final temperature of the combined metals is 48.87 °C.
given that :
weight of gold , m= 10.7 g
temperature, T = 19.8 °C
weight of iron , m = 18.7 g
temperature, T = 53.3 °C
final temperature t = ?
specific heat for gold , c = 0.12 J/ g °C
specific heat for iron , c = 0.45 J/ g °C
now, using the specific heat formula we get :
( mc ΔT ) + ( mc ΔT ) = 0
( 10.7 × 0.12 ×( t - 19.8 ) + ( 18.7 × 0.45 × (t - 53.3 ) = 0
(1.28 t - 25.4) + ( 8.41 t - 448.2 ) = 0
9.69 t = 473.6
t = 48.87 °C
Thus, A sheet of gold weighing 10.7 g and at a temperature of 19.8 °C is placed flat on a sheet of iron weighing 18.7 g and at a temperature of 53.3 °C. the final temperature of the combined metals is 48.87 °C.
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A single electron in an orbital has quantum numbers n = 2, ℓ = 0, mℓ = 0, ms = ½. what are the quantum numbers for the next electron added to this atom?
The quantum numbers for the next electron added to this atom are n = 2, ℓ = 0, mℓ = 0, ms = -½
The set of numbers used to explain the placement and strength of the electron in an atom are called quantum numbers. There are 4 quantum numbers, particularly, main, azimuthal, magnetic, and spin quantum numbers. The values of the conserved portions of a quantum gadget are given by quantum numbers.
The price of n tiers from 1 to the shell of the outermost electron of that atom. The important quantum variety may be determined by way of searching the period (numbered row) of the element on the periodic table. The principal quantum numbers of electrons inside the S-block and P-block are similar to the period range.
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30.The type of chemical reaction represented by the following equation is....HBr + NaOH ---> H2O + NaBrSelect one:a. decomposition. b. double displacement.c. single displacement.d. synthesis.
Answer:
b. Double displacement.
Explanation:
It is a double displacement reaction, because in this case, hydrogen atom in HBr is replaced by a sodium atom (from NaOH), and the sodium atom (in NaOH) is replaced by another H atom from HBr molecule, to form H2O.
According to Newton's Second Law, which of the following is TRUE?
Answer: the second one
Explanation:
Answer:
there's no answer choices?
7. A given sample of gas is held in a container with the volume of 6.02 L with a temperature of 59.5℃ at a pressure of 1.20 atm. What is the final pressure when the sample of gas is administered to a new volume of 10.0 L at 20.2℃?
The final pressure when the sample of gas is administered to the new volume and temperature is 0.64 atm.
What is the final pressure when the sample of gas?Combined gas law put together both Boyle's Law, Charles's Law, and Gay-Lussac's Law. It states that "the ratio of the product of volume and pressure and the absolute temperature of a gas is equal to a constant.
It is expressed as;
P₁V₁/T₁ = P₂V₂/T₂
Given the data in the question;
Initial volume V₁ = 6.02LInitial pressure P₁ = 1.20 atmInitial temperature T₁ = 59.5℃ = ( 59.5 + 273.15 )K = 332.65KFinal volume V₂ = 10.0L Final temperature T₂ = 20.2℃ = ( 20.2 + 273.15 )K = 293.35KFinal pressure P₂ = ?To determine the final pressure of the gas, plug the given values into the formula above and solve for P₂.
P₁V₁/T₁ = P₂V₂/T₂
P₁V₁T₂ = P₂V₂T₁
P₂ = P₁V₁T₂ / V₂T₁
P₂ = ( 1.20 atm × 6.02L × 293.35K ) / ( 10.0L × 332.65K )
P₂ = ( 2119.1604 KLatm ) / ( 3326.5 KL )
P₂ = 0.64 atm
Therefore, the final pressure of the gas is 0.64 atm.
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Which of the following is a combination reaction?A) C) N2 (g) + 02 (g) → 2NO (g)-BB) KOH (aq) + HNO3 (aq) → HN20 (/) + KNO3 (aq)CA) CaCl2 (aq) + Na2SO4 (aq) → CaSO4 (s) + 2NaCl (aq)DD) AgNO3 (aq) + NaCl (aq) - AgCl (s) + NaNO3 (aq)
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
The only option that follows this description of Combination reaction is the first reaction:
N2 + O2 -> 2 NO
FOR 100 PLEASE HELP A legend is a traditional story that explains something in real life. Sometimes they are accepted as true, but sometimes they are fantastical and just plain fun. There are many legends that surround the North Star explaining its creation as well as why it is stationary.
Take some time to research some of the legends of the North Star. After you have had a chance to read several of them, create your own fantastical story of the North Star. It can be how it came to be or explain why it is stationary.
The north star are stationary because it is positioned close to earth axis.it is the brightest star in the constellation.
Star is a luminous celestial body of gas which are mostly hydrogen and helium that shines and radiate energy sources. north star named as north star because its location is exactly above north pole. north star having some spiritual meaning , it is also called as polaris. north star is in the same location every night unlike all the other star. it is the brightest star in the constellation.
Thus, The north star are stationary because it is positioned close to earth axis.it is the brightest star in the constellation.
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A 51.72 g sample of a substance is initially at 23.5 °C. After absorbing 2547 J of heat, the temperature of the substance is 123.4 °C. What is the specific heat ( ) of the substance?
The heat absorbed or released by a substance is given by the following formula:
[tex]Q=m\cdot Cp\cdot(T2-T1)[/tex]Where Q is the heat absorbed or released, m is the mass of the substance, Cp is the specific heat, T2 is the final temperature and T1 is the initial one.
We know the values of Q, m, T2 and T1 because they are given by the question statement, and we have to find the value of Cp.
Solve the equation for Cp and use the given values to find its value:
[tex]\begin{gathered} Cp=\frac{Q}{m\cdot(T2-T1)} \\ Cp=\frac{2547J}{51.72g(123.4\degree C-23.5\degree C)} \\ Cp=\frac{0.49J}{g\degree C} \end{gathered}[/tex]The specific heat of the substance is 0.49J/g°C.
A solution is made using 80.1 g of dimethyl ether (MM = 46.07 g/mol) and 110.0 g of methanol (MM = 32.04 g/mol). What is the molality of the dimethyl ether in the solution?
The molality of the dimethyl ether in the solution is 15.8m
What is molarity ?
Molality (m), or molal concentration, is the amount of a substance dissolved in a certain mass of solvent. It is defined as the moles of a solute per kilograms of a solvent.
Moles of dimethyl ether= 80.1/46.07 = 1.74 moles
Molarity = moles of solute/ mass of solvent * 1000
1.74/110*1000 = 15.8m
The molality of the dimethyl ether in the solution is 15.8m
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Consider the following reaction for the production of NO2.2 NO(g) + O2(g) → 2 NO2(g)What mass of O2 in g is required to produce 15 L NO2 at 344 K and 752 mm Hg? (R = 0.08206 L⋅atm/mol⋅K)
The question requires us to calculate the mass of reactant (O2) necessary to obtain 15 L of the product (NO2) under the conditions given.
The following information was provided by the question:
- Balanced chemical reaction: 2 NO(g) + O2(g) → 2 NO2(g)
- Final volume of NO2: 15 L
- Pressure: P = 752 mmHg
- Temperature: 344 K
- Gas constant: R = 0.08206 L⋅atm/mol⋅K
To solve this question, we'll need to go through the following steps:
1) calculate the number of moles that corresponds to 15 L of NO2, considering the temperature and pressure given;
2) use the stoichiometric relation to calculate the necessary amount of O2 to produce the previously calculated number of moles of NO2
3) use the molar mass of O2 and the value calculated on step 2 to obtain the necessary mass of O2
Next, we'll solve the problem following these steps:
1) To calculate the number of moles of NO2, we'll use the following equation:
[tex]P\times V=n\times R\times T[/tex]where P is the pressure, V is the volume of gas, n is the number of moles, R is the constant of gases and T is the temperature.
If we rearrange the equation to calculate the number of moles, we'll have:
[tex]n=\frac{P\times V}{R\times T}[/tex]Note that the problem provided all necessary information for this calculation, but the pressure given (752 mmHg) needs to be converted into atm to match the constant provided.
To do that, we'll use the following:
1 atm = 760 mmHg
Thus, we need to divide the value provided by 760:
[tex]P=752\text{ mmHg}\times\frac{1\text{ atm}}{760\text{ mmHg}}=0.989\text{ atm}[/tex]Now, we can apply the values of pressure, volume and temperature, as well as the constant provided, to the equation written above:
[tex]n=\frac{(0.989\text{ atm)}\times(15\text{ L)}}{(0.08206\text{ L.atm/mol.K)}\times(344\text{ K)}}=0.525\text{ mol}[/tex]So far, we have that the volume of NO2 to be produced (15 L) corresponds to 0.525 mol under the conditions of pressure and temperature provided.
2) Next, we use the chemical reaction to calculate the number of moles of O2 required to produce 0.525 mol of NO2.
From the reaction, we have that 1 mol of O2 leads to 2 mol of NO2. Then, we use this to calculate how many moles of O2 would produce 0.525 moles of NO2:
1 mol O2 --------------- 2 mol NO2
x -------------------------- 0.525 mol NO2
Solving for x, we have:
[tex]x=\frac{(1\text{ mol O2)}\times(0.525\text{ mol NO2)}}{(2\text{ mol NO2)}}=0.263\text{ mol O2}[/tex]Now, we know that 0.263 moles of O2 are necessary to produce 15 L of NO2
3) The last step is calculate the mass of O2 that corresponds to 0.263 moles of this compound.
To do this, we need the molar mass of O2. Since the atomic mass of oxygen is 15.99 u, the molar mass of O2 is:
molar mass O2 = (2 * 15.99) = 31.98 g/mol
With this information, we can calculate the mass of 0.263 moles of O2:
1 mol O2 -------------------- 31.98 g O2
0.263 mol O2 ------------ y
Solving for y, we have:
[tex]y=\frac{(0.263\text{ mol O2)}\times(31.98\text{ g O2)}}{(1\text{ mol O2)}}=8.41\text{ g O2}[/tex]Therefore, the mass of O2 necessary to produce 15 L of NO2 under the conditions given is 8.41 g.
In Peft A, we saw that the theoretical yield of aluminum oxide is 1.50 mol. Calculate the percent yield if the actual yield ofaluminum oxide is 0.885 mol .Express your answer with the appropriate units.D View Available Hint(s)
Explanation:
The theoretical yield of our reaction is 1.50 moles, the actual yield of aluminum oxide is 0.885 moles. The percent yield is:
percent yield = actual yield/theoretical yield * 100 %
percent yield = 0.885 moles/(1.50 moles) * 100 %
percent yield = 59.0 %
Answer: The percent yield is 59.0 %.
What do I do to fill out the table, what belongs where ?
1) Write the proper formula for Mg2+ and Br-
Balance the charges.
Mg2+: Multiply by 1. This gives a total of two positive charges.
Br-: Multiply by 2. This gives a total of two negative charges.
Use multipliers as subscripts
[tex]\text{MgBr}_2[/tex]2) Write the proper formula for Al3+ and O2-
Al3+: Multiply by 2. This gives a total of six positive charges.
O2-: Multiply by 3. This gives a total of six negative charges.
Use multipliers as subscripts
[tex]Al_2O_3[/tex]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.
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.
F-F covalent bond is slightly polarTrue or false and why?
Answer:
False. F-F would be a covalent apolar molecule.
Explanation:
As we have two elements bonded of the same element, in this case, F (fluorine), they would be sharing electrons, making that the bonding is covalent but there are no charges, because they're the same element, so it would be a completely covalent apolar molecule.
Write formulas or names as appropriate for each of the following acids. 1. Hydroiodic acid 2. Carbonic acid 3. Chlorous acid 4. Sulfuric acid 5. Phosphorous acid 6. HCN (aq) 7. H2C2O4 (aq) 8. HNO2 (aq) 9. H2Cr2O7 (aq) 10. HMnO4 (aq)
ANSWER
The chemical formula of Hydroiodic acid is HI
EXPLANATION
Hydroiodic acid is formed from a reaction between hydrogen and iodine resulting into an aqueous solution of Hydrogen iodide
[tex]\begin{gathered} H^{+_{}}+I^-\rightarrow HI_{(aq)} \\ \end{gathered}[/tex]Hence, the chemical formula of Hydroiodic acid is HI
Use the reaction and bond information to answer the question
In this question, we have the following reaction:
C2H6 -> C2H4 + H2
As we can see, we had two hydrogen atoms being decomposed from the original molecule, therefore we had 2 bonds being broken, and bond breaking is an endothermic process, because it requires energy in order to occur, therefore we have as the best answer, letter D, or 4th option
A process that may lead to gamates containing too many or too few chromosomes is called?
(A) Recombination
(B) Crossing over
(C) Karyogenesis
(D) Nondisjunction
Answer:
D) Nondisjunction
Explanation:
Nondisjunction happens when a chromosome pair doesn't separate during meiosis. A result is one of the gamates has to any chromosome, while others have much less.