Answer:
-411 kj
Explanation:
We solve by using this formula
∆U = ∆Q + ∆W
This formula is the first law of thermodynamics
Change in internal energy U = +241
Heat gained by system Q = 652
Putting the value into the equation
+241 = 652 + W
Workdone = 241 - 652
Workdone = -411 kj
Since work done is negative it means that work was done by the system
8th silberberg, sample problem 13.5. find the concentration of calcium ion (in ppm) in a 2.43 g pill that contains 44.6 mg of ca2 . enter to 0 decimal places.
The concentration of calcium ion in the pill is 18,320 ppm.
To calculate the concentration of calcium ion in parts per million (ppm), we need to determine the mass of calcium ion in the pill and divide it by the mass of the pill, then multiply by 1,000,000.
Mass of the pill = 2.43 g
Mass of Ca^2+ = 44.6 mg = 0.0446 g
Now, we can calculate the concentration in ppm:
Concentration of Ca^2+ (ppm) = (Mass of Ca^2+ / Mass of the pill) * 1,000,000
Concentration of Ca^2+ (ppm) = (0.0446 g / 2.43 g) * 1,000,000
Concentration of Ca^2+ (ppm) ≈ 18,320 ppm
The concentration of calcium ion in the pill is approximately 18,320 ppm.
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What does it mean to dilute a solution?
Answer:
Dilution is the process of decreasing the concentration of a solute in a solution, usually simply by mixing with more solvent like adding more water to the solution
alcohol has a polar area at the top of the molecule and a large area that is not polar. the entire water molecule is polar. explain how these differences in polarity between alcohol and water can help explain why water evaporates more slowly than alcohol?
Water evaporates more slowly than alcohol because water has more surface tension and more cohesive force than alcohol, So it takes more time for water to evaporate than for alcohol.
In alcohol, only O-H present is hydrophilic i.e. polar. Apart from this alcohol has a large hydrocarbon group i.e. C-H present in it, which is non-polar in nature. As a result, the attractive force between the atoms in alcohol is less. As a result, during boiling, the bonds between the atoms vibrate and break quickly. So alcohol evaporates faster.
In water, the entire molecule is polar. So there exists a strong attractive force between them. So the cohesive force is more in the case of water as compared to that of alcohol. As water is boiled the O-H bonds start to vibrate, since the bond is stronger, it requires higher energy for boiling. Thus it evaporates slower.
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WILL GIVE BRANLIEST!! EASY BUT I WAS TO LAZY TO LEARN!! WILL FOREVER BE GREATFUL!!! WILL GIVE BRANLIEST!! EASY BUT I WAS TO LAZY TO LEARN!! WILL FOREVER BE GREATFUL!!!
WILL GIVE BRANLIEST!! EASY BUT I WAS TO LAZY TO LEARN!! WILL FOREVER BE GREATFUL!!!
5. What type of reaction would the heat calculation in previous question be classified as?
A) Natural
B) Chemical
C) Endothermic
D) Exothermic
7. What causes the volume to change in gases? (Choose all that apply)
A) Density
B) Temperature
C) Shape of container
D) Pressure
Answer:
for the first one we need the previous question to be able to answer it. for the second one density and temperature
Explanation:
What is hydrochloric acid used for?
Cleaning
Warfare
Middle school science class
to make glue
Answer:
To make glue. aaaaaaaaa
Answer:
Cleaning
Explanation:
Hydrochloric acid is an ingredient in household cleaners because it helps clean tough stains.
Here is the skeleton reaction for combustion of methane (natural gas)
CH4+O2→CO2+H2O
What are the reactants of this reaction?
Please help me :(
Answer:
CH4 and O2
Explanation:
The reactants of a chemical reaction are those that are on the left side of the chemical equation. In this case, methane (CH4) and oxygen (O2) which are on the left side, are the reactants.
KOH is used to precipitate each of the cations from the respective solutions. Determine the minimum hydroxide required for the precipitation to begin
0.085 M Fe(NO3)2 Ksp (Fe(OH)2) = 4.87x10^-17
The minimum hydroxide concentration required for the precipitation of [tex]Fe(OH)_2[/tex] to begin is [tex]1.691* 10^-^8 M.[/tex]
How do we calculate?The balanced chemical equation for the precipitation reaction is:
[tex]Fe(OH)_2[/tex](s) ⇌ [tex]Fe^2^+[/tex](aq) + [tex]2OH^-[/tex](aq)
Ksp = [tex][Fe^2^+][OH^-]^2[/tex]
Ksp [tex]Fe(OH)_2[/tex] = [tex]4.87*10^-^1^7[/tex]
Ksp = [tex][Fe^2^+][OH^-]^2[/tex]
[tex]4.87*10^-^1^7[/tex] = (0.085)(2x)²
[tex]4.87*10^-^1^7[/tex] = 0.17x²
x² =[tex]4.87*10^-^1^7[/tex] / 0.17
x² = [tex]2.8647* 10^-^1^6[/tex]
x = [tex]1.691*10^-^8[/tex] M
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Is it true that all atoms strive to have eight electrons in their outermost
shell?
YESS It is true!!. In general, atoms are most stable, least reactive, when their outermost electron shell is full. Most of the elements important in biology need eight electrons in their outermost shell in order to be stable, and this rule of thumb is known as the octet rule.
Hydrochloric acid can dissolve solid iron according to the following reaction
Fe(s)+2HCl(aq)>FeCl2(aq) + H2(g). What minimum mass of HCl in grams would you need to dissolve a 2.3g iron bar on a padlock? Also I need to know how much H2 would be produced by the complete reaction of the iron bar (but I can ask this as a seperate question if necessary).
The mass of the HCl that is required for the reaction is 2.92 g
The mass of the hydrogen gas produced is 0.08 g
What is stoichiometry?Number of moles of the iron = 2.3 g/56 g/mol
= 0.04 moles
We have that 1 mole of the iron reacts with 2 moles of HCl
0.04 moles of iron would react with 0.04 * 2/1
= 0.08 moles
Mass of the HCl required = 0.08 moles * 36.5 g/mol
= 2.92 g
We have that the mole ratio of the iron and the hydrogen is 1:1 kit then follows that mass of the hydrogen produced would now be;
0.04 moles * 2 g/mol
= 0.08 g
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Pls someone help me hurry pls someone?????
Answer:
Becxause there is no whee5r else for the flame to go out fromk
Explanation:
NaCl
Na = 1
Cl=1
Answer:
19. because fire needs oxygen or air to keep the fire burning.
20.A molecule of sodium chloride, NaCl, consists of one atom each of sodium and chlorine. Hence, each molecule of NaCl has 2 atoms total. Similarly, we can calculate the total number of atoms in 1 mole of sodium chloride. Since 1 molecule contains 1 atom each of Na and Cl, 1 mole of NaCl will contain 1 mole each of Na and Cl.
Explanation:
Hope this helps!
A researcher is trying to identify whether household substances are basic. Which approach would BEST help the researcher
investigate whether substances are basic?
O A. Mix each substance with a weak base and record the results.
OB. Test each substance with red litmus paper.
O C. Observe each substance and record its color.
OD Test each substance with blue litmus paper.
Answer:
I think B
Explanation:
Red litmus paper is used more to find bases, blue litmus paper changes better when coming to find acids. So I believe it is B
The best approach best investigate whether substances are basic is to test each substance with red litmus paper.
What is basic compound?Basic compounds are those which have a pH value in between the range of 7.1 to 14.
Red litmus paper changes its color from red to blue when comes in the contact of basic compounds. So to check the basicity of household substance we should use red litmus paper.
Bases are reacting with only acids means bases shows no reaction with base and if we use weak base then we will not get the desired result as weak bases are partially dissociates only.Color will not gives idea about basicity and acidity.Red litmus paper is used to test the acidity of substance as it turns blue when comes in contact of acids.Hence test each substance with red litmus paper.
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draw the major e2 reaction product formed when (1r,2s,4s)‑2‑chloro‑4‑methyl‑1‑(propan‑2‑yl)cyclohexane reacts with hydroxide ion in dmso. chirality is graded.
The major E2 reaction product formed when (1R,2S,4S)-2-chloro-4-methyl-1-(propan-2-yl)cyclohexane reacts with hydroxide ion in DMSO is (1S,2R,4S)-2-methyl-1-(propan-2-yl)cyclohexene.
In an E2 (elimination) reaction, a hydrogen atom and a leaving group are removed from adjacent carbon atoms, resulting in the formation of a double bond. In this case, the leaving group is the chloride ion (Cl-) and the hydrogen atom is removed from the carbon adjacent to the chlorine atom.
The given starting compound, (1R,2S,4S)-2-chloro-4-methyl-1-(propan-2-yl)cyclohexane, has a chiral center at carbon 2, which is marked as (S). When the hydroxide ion (OH-) attacks the carbon adjacent to the chlorine atom, the chlorine leaves and a hydrogen from the adjacent carbon is also removed. The resulting product is (1S,2R,4S)-2-methyl-1-(propan-2-yl)cyclohexene.
It's important to note that the stereochemistry of the starting compound and the resulting product is represented by the (R) and (S) designations, indicating the arrangement of the substituents around the chiral carbon atoms.
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3. How much energy is needed to raise 45 grams of water from 40°C to 115 °C?
The specific heat capacity of ice is 2.06 J/g °C
The specific heat capacity of water is 4.18 J/g °C
The specific heat capacity of steam is 2.02 J/g °C
The heat of fusion of water is 334 J/g
The heat of vaporization of water is 2260 J/g.
Answer:
Q = 114349.5 J
Explanation:
Hello there!
In this case, since this a problem in which we need to calculate the total heat of the described process, it turns out convenient to calculate it in three steps; the first one, associated to the heating of the liquid water from 40 °C to 100 °C, next the vaporization of liquid water to steam at constant 100 °C and finally the heating of steam from 100 °C to 115 °C. In such a way, we calculate each heat as shown below:
[tex]Q_1=45g*4.18\frac{J}{g\°C}*(100\°C-40\°C)=11286J\\\\Q_2=45g* 2260 \frac{J}{g} =101700J\\\\Q_3=45*2.02\frac{J}{g\°C}*(115\°C-100\°C)=1363.5J[/tex]
Thus, the total energy turns out to be:
[tex]Q_T=11286J+101700J+1363.5J\\\\Q_T=114349.5J[/tex]
Best regards!
The characteristics of metallic bonds fit nicley into a predictable pattern. True or False?
Answer:
True
Explanation:
DON'T GIVE BRAINLIEST TO THE FILE EXPLOITER!!!!
When a small piece of sodium metal is dropped into a beaker of water, hydrogen gas (H2) and a solution of sodium hydroxide (NaOH) are products. The solution becomes warm.
Answer:
The reaction is exothermic as the solution becomes warm.
Explanation:
Hello there!
In this case according to the described reaction between sodium metal and water, we can write up the chemical equation whereas the products turn out to be sodium hydroxide and hydrogen gas:
[tex]2Na+2H_2O\rightarrow 2NaOH+H_2[/tex]
Moreover, these reactions are known to be highly exothermic, for that reason the solution becomes warm as the reaction releases heat as it goes to completion.
Best regards!
The use of uranium-238 to determine the age of a geological formation is a beneficial use of
O 1.
nuclear fusion
2.
nuclear fission
3.
radioactive isomers
4.
radioactive isotopes
Answer:
4- radioactive isotopes
Explanation:
I don't remember exactly but this question was on the regents
Uranium-238 is a non- fissile element. It is a radioactive isotope that can be best used to determine geological formations. Thus, option 4 is correct.
What are radioactive isotopes?Radioactive isotopes are elements that have an unstable atomic nucleus and can undergo radioactive decay to produce new particles and energy. They have the same atomic number as that of their parent species.
Isobars are a substance that has atomic mass and do not include uranium. Nuclear fusion and fission are the processes of nuclear energy that combine or splits the unstable nucleus to form a new particle.
Therefore, option 4. Uranium-238 is a radioactive isotope.
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if δg° of the following reaction is –110 kj/mol, what is e°cell? (f = 96,500 C • mol^-1) A^3-(aq) + 3B(s) → A(s) +3B- (aq)
a. + 0.38 V b. - 0.09 V c. - 0 38 V d. + 0.00038 V e. + 0.09 V
The standard cell potential (E°cell) of the reaction is found to be + 0.38 V, hence, option A is correct.
We will be usig the equation,
E°cell = (ΔG° / -nF) standard Gibbs free energy change is ΔG°, number of electrons transferred in the balanced equation is n, and Faraday constant (96,500 C/mol) is F. In the given reaction, 3 electrons are transferred, so n = 3.
Given ΔG° = -110 kJ/mol and F = 96,500 C/mol, we can substitute these values into the equation to calculate E°cell,
E°cell = (-110,000 J/mol / (-3 * 96,500 C/mol))
E°cell = 0.38 V
Therefore, the answer is, a. + 0.38 V
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How many moles of oxygen are required in order to produce 4 moles of
water?
At another temperature, the rate constant is 3.25 M-2 s-1. What is the rate at this temperature for the
given concentrations?
Answer:
It's 0.00015
Explanation:
got it right on edge 2021
For a galvanic cell that uses the following two half-reactions, write the balanced equation and how many moles of Pb(s) are oxidized by five moles of Cr2O72-?
Cr2O72-(aq) + 14 H+(aq) + 6 e- → 2 Cr3+(aq) + 7 H2O(l)
Pb(s) → Pb2+(aq) + 2 e-
(Please show work and thank you for taking the time to answer.)
The balanced equation is 6 Pb(s) + 6 Cr2O72-(aq) + 42 H+(aq) → 12 Cr3+(aq) + 42 H2O(l) + 6 Pb2+(aq). 6 moles of Pb(s) are oxidized for every 6 moles of Cr2O72- consumed. If 5 moles of Cr2O72- are used, it will oxidize 5 moles of Pb(s).
First, we need to balance the two half-reactions. Let's start with the reduction half-reaction of Cr2O72-: Cr2O72-(aq) + 14 H+(aq) + 6 e- → 2 Cr3+(aq) + 7 H2O(l). To balance the oxygen atoms, we add 7 H2O to the left side: Cr2O72-(aq) + 14 H+(aq) + 6 e- → 2 Cr3+(aq) + 7 H2O(l). Next, we balance the hydrogen atoms by adding 14 H+ to the right side:
Cr2O72-(aq) + 14 H+(aq) + 6 e- → 2 Cr3+(aq) + 7 H2O(l) + 14 H+(aq)
Now, let's balance the oxidation half-reaction of Pb: Pb(s) → Pb2+(aq) + 2 e-. The equation is already balanced. To combine the two half-reactions, we multiply the reduction half-reaction by 6 and the oxidation half-reaction by 6 to ensure that the electrons cancel out: 6 Cr2O72-(aq) + 42 H+(aq) + 36 e- → 12 Cr3+(aq) + 42 H2O(l) + 84 H+(aq). 6 Pb(s) → 6 Pb2+(aq) + 12 e-. Now, we can write the balanced equation: 6 Pb(s) + 6 Cr2O72-(aq) + 42 H+(aq) → 12 Cr3+(aq) + 42 H2O(l) + 6 Pb2+(aq).
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4.0 g of sodium hydroxide NaOH was dissolved in sufficient water to make up 125 mL of solution.
A) Find the concentration of the solution.
B) What mass of sodium hydroxide could be obtained by heating a 20 mL sample of this solution to dryness?
C) If 30 mL of the solution were mixed with sufficient water to produce 480 mL of a more dilute solution, what would be the concentration of the dilute solution?
D) If 200 mL of the more dilute solution were then mixed with 100 mL of the more concentrated solution, what would be the concentration of the mixed solution?
Answer:
(A) 0.80 M
(B) 0.64 g
(C) 0.050 M
(D) 1.6 M
Explanation:
(A)
Convert 4.0 g to moles with molar mass. Convert 125 mL to L.
4.0 g x (1 mol/39.998 g) = 0.100 mol
125 mL x (1 L/1000 mL) = 0.125 L
Molarity = mol/L
Molarity = 0.100 mol/0.125 L = 0.80 M
(B)
Find moles of NaOH with the molarity you just found. And convert 20 mL to L.
Molarity = mol/L
0.80 M = mol/0.020 L
mol = 0.016
Convert moles to grams with molar mass.
0.016 mol x (39.998 g/1 mol) = 0.64 g
(C)
You know the molarity of a NaOH solution (Part A). 30 mL initial volume and 480 mL final volume are given. Dilution question so use the dilution formula.
M1V1 = M2V2
(0.80 M)(30 mL) = (M2)(480 mL)
M2 = 0.050 M
(D)
Dilution question again, use the dilution formula.
M1V1 = M2V2
(0.80 M)(200 mL) = (M2)(100 mL)
M2 = 1.6 M
What is a chemical bond?
how to find the concentration of a solution that is 100 times less than another solution
By dividing the concentration of the reference solution by 100, you will obtain the concentration of the desired solution, which is 100 times less concentrated than the reference solution.
To find the concentration of a solution that is 100 times less than another solution, you can follow these steps:
1. Determine the concentration of the reference solution. Let's denote it as [A]₀.
2. Calculate the concentration of the desired solution. Let's denote it as [A].
3. Since the desired solution is 100 times less concentrated than the reference solution, you can divide the concentration of the reference solution by 100 to obtain the concentration of the desired solution:
[A] = [A]₀ / 100
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a. Identify the different parts of the chemical equation below. (2 points) A(s) B(l) C(g) D(aq) 1. A: _________________________
2. B: _________________________
3. C: _________________________
4. D: _________________________
5. (s): _________________________
6. (l): _________________________
7. (g): _________________________
The different parts of the chemical equation below are identified as follows:
1. A: Solid
2. B: Liquid
3. C: Gas
4. D: Aqueous
5. (s): Solid
6. (l): Liquid
7. (g): Gas
A chemical equation is a symbolic representation of a chemical reaction where reactants are written on the left side and products on the right side. These reactants and products are identified with their respective states such as solid, liquid, gas, and aqueous.
The symbols for the physical states of the reactants and products are included in parentheses, alongside their respective chemical formulas.
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List and describe the 2 main causes of species extinction happening today.
Answer:
habitat destruction, overexploitation, climate change, nitrogen pollution, and invasive species.
Explanation:
Main Modern Causes of Extinction:
habitat destruction - the process by which a natural habitat becomes incapable of supporting its native species.
overexploitation - harvesting a renewable resource to the point of diminishing returns.
climate change - includes both global warmings driven by human emissions of greenhouse gases and the resulting large-scale shifts in weather patterns.
nitrogen pollution - a form of water pollution, refers to contamination by excessive inputs of nutrients.
invasive species - an introduced organism that negatively alters its new environment.
Which of the following pictures is a chemical change, and which is a
physical change? Explain in the boxes next to the picture.
Plz explain
Answer:
left is chemical because its chemicals, and right is physical because the ice cream is melting and thats physical
Explanation:
What is an example of an organism that undergoes binary fission?
Unicellular organisms such as amoeba and leishmania undergo binary fission.
What is binary fission?Binary fission can be described as a form of asexual reproduction where an organism divides into two, each part having one copy of genetic material.
Binary fission can be described as a kind of asexual reproduction observed in prokaryotes and a few single-celled eukaryotes. In asexual reproduction, there is a separation of the parent cell into 2 new daughter cells. This process occurs with the division and duplication into two parts.
Binary fission is a primary of reproduction in prokaryotic organisms. Binary Fission happens without spindle apparatus formation in the cell. The single DNA molecule starts replication and attaches each copy to parts of the cell membrane.
Prokaryotes and eukaryotes such as euglena reproduce via binary fission. This process is rapid, and its speed varies in species. The time needed by bacteria to double the cells it has is called known as doubling time.
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Sometimes the number of electrons in an atom changes. These atoms are called what
Answer:
ions
Explanation:
What does the period number tell about the energy levels occupied bye electrons in an atom
Answer:
The period number tells which is the highest energy level occupied by the electrons.
Explanation:
The period number (denoted by n) is the outer energy level that is occupied by electrons in an atom.The period number that an element is in, is the number of energy levels that the element has.When we move across a period from left to right in a periodic table the number of electrons in atoms increases within the same orbit.consider the reaction 4 ko2(s) 2 co2(g) → 2 k2co3(s) 3 o2(g). how much oxygen is produced at stp if 10.5 moles of carbon dioxide are used at stp?
In the given reaction, 4 moles of KO2 react to produce 3 moles of O2. Therefore, if 10.5 moles of carbon dioxide (CO2) are used at STP, an equal amount of oxygen (O2) is produced. Hence, 10.5 moles of O2 will be generated.
According to the balanced chemical equation, the reaction 4 KO2(s) + 2 CO2(g) → 2 K2CO3(s) + 3 O2(g) shows that for every 4 moles of KO2, 3 moles of O2 are produced. Therefore, the molar ratio between KO2 and O2 is 4:3.
Since 10.5 moles of CO2 are used, we can use the stoichiometry of the reaction to determine the amount of O2 produced. As the reaction equation does not involve CO2, the amount of CO2 used does not directly affect the production of O2. Thus, 10.5 moles of CO2 will yield an equal amount of O2, resulting in 10.5 moles of O2 being produced at STP.
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