Answer:
Atomic weight and valence electrons
Explanation:
These variables allow Mendeleev to place each element in a certain row and column. The table comprises 7 rows and 18 columns.
A students finds a FeNO3 . 3H2O solution with a 1.8 concentration . She uses a a 2 cm wide cuvette in a colorimeter to measure the absorbance. The molar absorptivity of CuSO4 . 5H2O is 42.243 M-1cm-1
What is the Absorbance of the solution?
The absorbance of a solution that has a concentration of 1.8 is 152.75.
How to calculate absorbance?The absorbance of a substance can be calculated using Beer's law equation as follows:
A = εmCl
Where;
A = absorbanceεm = molar absorptivityC = concentration of solutionl = path lengthAccording to this question, the following information are given:
A = ?εm = 42.243 M-1cm-1C = 1.8l = 2cmA = 42.43 × 1.8 × 2
A = 152.75
Therefore, the absorbance of a solution that has a concentration of 1.8 is 152.75.
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How many moles of oxygen are required to burn in one mole of C4H8 completely?
Answer:
6 moles of oxygen is required to burn 1 mole of C4H8 completely
Explanation:
reaction is C4H8 + (6)O2 ------ (4)CO2+ (4)H2O
During this chemical reaction energy is absorbed. In the chemistry lab, this would be indicated by a decrease in temperature or if
the reaction took place in a test tube, the test tube would feel colder to the touch. Reactions like this one absorb energy because
A) the reaction requires activation energy.
B) the reactants have less potential energy than the products.
C)the reactants have more potential energy than the products.
D)the mass of the products is greater than the mass of the reactants.
Reactions like this one absorb energy because the reactants have less potential energy than the products.
What is an Endothermic reaction?This is the type of reaction in which the reactants absorb heat energy from the surroundings to form products.
This brings about a decrease in the temperature as a result of the reactants having less potential energy than the products thereby making option B the most appropriate choice.
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The molar mass of water (h2o) is 18.0 g/mol. a sample of water has a mass of 18.0 g. how many moles of water are contained in this sample? 1.00 mole 18.0 moles 36.0 moles 324 moles
The moles of water are contained in the given sample is 1 mole.
How do we calculate moles?Moles of any substance will be calculated by using the below formula:
n = W/M , where
W = required mass
M = molar mass
Given molar mass of H₂O = 18.0 g/mol
Given mass of H₂O = 18.0 g
Moles of H₂O = 18.0 g / 18.0 g/mol = 1 moles
Hence option (1) is correct.
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Answer:
A. 1.00 Mole
Explanation:
edg 2023
Which of the following radioactive emissions is the least penetrating?
alpha particles
gamma rays
beta particles
Answer:
alpha particles
Explanation:
alpha particles the least penetrating but potentially most damaging and gamma rays the most penetrating. A beta particle, also called beta ray or beta radiation, is a high-energy, high-speed electron or positron emitted by the radioactive decay of an atomic nucleus during the process of beta decay.
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Firefighters’ uniform is coated with a plastic that is fire resistant. Identify the plastic from the given options.
A. Teflon
B. Melamine
C. PET
D. Polyester
Answer:
Melamine
Explanation:
Melamine is also a non recyclable plasticThis plastic has very high heat resistance and also bad heat and electricity conducter.So it's used by firefightersWhich of the following was not an invention of the Han period?
A. Porcelain
B. Wheelbarrow
C. Paper
D. Silk
Answer:
Silk! All the others were inventions of the Han period.
Explanation:
Silk fabric was invented in Ancient China. Legend has it that the process for making silk cloth was first invented by the wife of the Yellow Emperor, Leizu, around the year 2696 BC.
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When 55.8 g of Fe reacts with Cl2 according to the equation 2Fe + 3Cl2 --> 2FeCl3. How many moles of Cl2 are required to react with all the iron?
2.00 mol
1.00 mol
0.67 mol
1.50 mol
Answer:
1.50 moles
Balanced equation: 2Fe + 3Cl₂ --> 2FeCl₃
find moles of iron:
moles = mass/Mr
moles = 55.8/56
moles = 0.9964 moles
use molar ratio:
2Fe : 3Cl₂
2 : 3
moles of Cl₂ = (0.9964/2)*3 = 1.50 moles
Balancing chemical equation
Explanation:
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A mixture of 0.197 mol CO2 and 0.00278 mol H2O is held at 30.0 degrees celsius with a pressure of 2.50 atm. What is the partial pressure of each gas?
Considering the Dalton's partial pressure, the partial pressure of CO₂ is 2.465 atm and the partial pressure of H₂O is 0.035 atm.
Dalton's lawThe pressure exerted by a particular gas in a mixture is known as its partial pressure.
So, Dalton's law states that the total pressure of a gas mixture is equal to the sum of the pressures that each gas would exert if it were alone:
[tex]P_{T} =P_{1} +P_{2} +...+P_{n}[/tex]
where n is the amount of gases in the mixture.
Dalton's partial pressure law can also be expressed in terms of the mole fraction of the gas in the mixture. The mole fraction is a dimensionless quantity that expresses the ratio of the number of moles of a component to the number of moles of all the components present.
So in a mixture of two or more gases, the partial pressure of gas A can be expressed as:
[tex]P_{A} =x_{A} P_{T}[/tex]
Partial pressure of CO₂ and H₂OIn this case, you know:
[tex]n_{CO_{2} }[/tex]= 0.197 moles[tex]n_{H_{2}O }[/tex]= 0.00278 moles[tex]n_{T }=n_{CO_{2} }+n_{H_{2}O }[/tex]= 0.197 moles + 0.00278 moles= 0.19978 moles[tex]P_{T}= 2.50 atm[/tex]Then:
[tex]x_{CO_{2}} =\frac{n_{CO_{2}} }{n_{T} }=\frac{0.197 moles}{0.19978 moles} = 0.986[/tex][tex]x_{H_{2}O} =\frac{n_{H_{2}O} }{n_{T} }=\frac{0.00278 moles}{0.19978 moles} =0.014[/tex]Replacing in the Dalton's law:
[tex]P_{CO_{2} } =x_{CO_{2}} P_{T}[/tex]
[tex]P_{CO_{2} } =[/tex] 0.986× 2.50 atm
[tex]P_{CO_{2} } =[/tex] 2.465 atm
[tex]P_{H_{2}O } =x_{H_{2}O} P_{T}[/tex]
[tex]P_{H_{2}O } =[/tex] 0.014× 2.50 atm
[tex]P_{H_{2}O } =[/tex] 0.035 atm
Finally, the partial pressure of CO₂ is 2.465 atm and the partial pressure of H₂O is 0.035 atm.
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Which acid should be stored in plastic containers rather than in glass ones?
Answer:
sulphuric acid and nitric acid
Explanation:
The acids that should be stored in plastic containers rather than in glass ones are hydrofluoric acid, phosphoric acid, sulfuric acid, etc.
What are acids?
Acids are those solutions that are sour in taste and have lower pH to 7.
Hydrofluoric acid is highly corrosive, made up of hydrogen and fluorine.
Phosphoric acid is an important oxygen of phosphorus.
Thus, the acids that should be stored in plastic containers rather than in glass ones are hydrofluoric acid, phosphoric acid, sulfuric acid, etc.
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In a triprotic acid, which ka has the highest value?.
Answer:
The answer is Ka1
▬▬▬▬▬▬▬▬
When it comes to dissociation, Ka1 is fairly the most even-out level, classifying it as a Weak Acid.
What differentiates a weak from a strong acid?They must be fully separable into ions. If that's the case, you are dealing with a Strong acid.
If this is not the case, that would make the acid Weak.
▬▬▬▬▬▬▬▬
In conclusion, I hope this helps you and I hope you have a great day!
Can someone please help me? :( giving brainliest
Answer:
A and C
Explanation:
I chose these answers because a longer range of time would give a better representation of the climate.
Hope this helps! Please let me know if you need more help or think my answer is incorrect. Brainliest would be MUCH appreciated. Have a wonderful day!
A gas occupies a volume of 0.7 L at 10.1 kPa. What volume will the gas occupy at 101 kPa?
Answer:
7L
Explanation:
Divide 101 by 10.1(kPa) and you get 10.
10 x .7 = 7
The concept Boyle's law is used here to determine the new volume of gas . Boyle’s law was put forward by the Anglo-Irish chemist Robert Boyle in the year 1662. Here the new volume of the gas is 0.07 L.
What is Boyle's law?A gas law known as Boyle's law asserts that a gas's pressure is inversely proportional to its volume when it is held at a fixed temperature and of a given mass. To put it another way, as long as the temperature and volume of the gas remain constant, the pressure and volume of the gas are inversely proportional to one another.
For a gas, the relationship between volume and pressure (at constant mass and temperature) can be expressed mathematically as follows.
P = k*(1/V) ⇒ PV = k
For two different gases, the equation is:
P₁V₁ = P₂V₂
V₂ = P₁V₁ / P₂
10.1 × 0.7 / 101 = 0.07 L
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Hikers noticed that a sealed bag of potato chips puffs up when taken to the top of a mountain. suppose that at the valley floor below, the air pressure is 1.0 atm, the temperature is 25°c, and the volume of the bag is 0.985 l. at the top of the mountain, the temperature is 22°c and the bag has puffed up to 1.030 l. what is the air pressure on top of the mountain? type in your answer using the correct number of significant figures. formula: p1v1 t1 = p2v2 t2 atm
Gas law gives the relation between the volume, moles, pressure, and temperature of the gas. The air pressure at the top of the mountain is 0.945 atm.
What is Gas law?Gas law gives the direct relationship between the pressure and the volume of the gas with that of the temperature of the gas.
Given,
Initial pressure = 1.0 atm
Initial volume = 0.985 L
Initial temperature = 298.15 K
Final pressure = ?
Final volume = 1.030 L
Final temperature = 295.15 K
The final pressure at the mountain top is calculated as:
[tex]\begin{aligned} \rm \dfrac{P_{1}V_{1}}{T_{1}} &= \rm \dfrac{P_{2}V_{2}}{T_{2}}\\\\\dfrac{1 \;\rm atm \times 0.985 \;\rm L}{ 298.15 \;\rm K} &= \;\rm \dfrac{P_{2} \times 1.030 \;\rm L}{295.15\;\rm K}\\\\&= 0.945 \;\rm atm\end{aligned}[/tex]
Therefore, the pressure on the top of the mountain is 0.945 atm.
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A solution that has a high amount of hydrogen ions is called.
Answer:
a solution with high amount of hydrogen ions is called an acidic solution
N2(g)+3H2(g) 2NH3(g)
The equilibrium system described by this equation has
reactant molecule(s)
and
product gas molecule(s).
Considering the definition of chemical equation, the equilibrium system described by this equation has 4 reactant molecules and 2 product gas molecules.
Definition of chemical equationA chemical equation is a symbolic description used to describe the identities and relative quantities of the reactants and products involved in a chemical reaction.
The information contained in the chemical equation allows us to determine the substances that are transformed or modified in a reaction, called reactants or reagents, and the new substances that originate in a chemical reaction, called products.
The chemical equation must comply with the Law of conservation of matter. That is, the equation must indicate that the number of atoms of the reactants and products is equal on both sides of the reaction and that the charges are also equal.
Number of reactant molecule(s) and product gas molecule(s)In this case you know:
N₂ + 3 H₂ ⇄ 2 NH₃
You can observe that the number of H₂ is 3, while the number of N₂ is 1.
The number of molecules on the reactant side is the sum of hydrogen and nitrogen molecules. Then, the total number of reactant molecule is 4.
The number of product molecules are only the number of NH₃. Then, the number of product molecules are 2.
Finally, the equilibrium system described by this equation has 4 reactant molecules and 2 product gas molecules.
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Answer:
4 and then 2
Explanation:
After completing their tests, the students make recommendations on how to increase the final temperature of the
mixture
Based on the data in the table, select if the proposed improvements would increase or decrease the final
emperature of the mixture. Place a check mark in the appropriate box in each row.
Answer: test two
Explanation: it sits in between both
An aqueous solution turns litmus red. The ph of this solution could be
If an aqueous solution turns litmus red, the pH of the solution could be the range of 1 - 6.
What is an acid?An acid is a substance that is capable of producing only hydrogen ions (H+) when dissolved in water.
An acid posseses other unique characteristics and are as follows:
Acids are corrosive in their concentrated formAcids turn blue litmus redAcids are sour to tasteThe pH range of an acidic substance is between 1-6.
Therefore, if an aqueous solution turns litmus red, the pH of the solution could be the range of 1 - 6.
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what is the difference between bacteria and cancer cells
What units are appropriate to express specific heat?.
Answer:
joules per gram per degree (J/goC) or calories per gram per degree (cal/goC).
Explanation:
Answer:
Joules, Kelvin, or calories
Explanation:
175 ml of a 1.6 m solution of kcl is diluted to a new volume of 1.0 l. what is the new concentration of the solution?
The new concentration of the KCl solution after mixing 1 L new volume is 0.28 M.
How do we calculate the concentration?Concentration in terms of molarity will be calculated by using the below equation as:
M₁V₁ = M₂V₂, where
M₁ = molarity of old KCl solution = 1.6 M
V₁ = volume of old KCl solution = 175 mL = 0.175 L
M₂ = molarity of new KCl solution = ?
V₂ = volume of new KCl solution = 1 L
On putting all these values on the above equation, we get
M₂ = (1.6)(0.175) / (1) = 0.28 M
Hence resultant concentration is 0.28 M.
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What is the percent composition of hydrogen in beryllium hydride, if 69.6g of beryllium with 15.6g of hydrogen to produce 85.2g of BeH2?
The percent composition of hydrogen is 18.3%.
What is percent composition?
The term percent composition refers to the percentage of a particular component in a compound. It is contained as the ratio of the mass of that component to the total mass multiplied by 100.
From the law of conservation of mass, total mass of beryllium hydride(BeH2) = 85.2 g
Mass of hydrogen = 15.6 g
Percent composition of hydrogen = 15.6 g/ 85.2 g × 100/1 = 18.3%
Holly’s camp stove uses butane (C4H10). This fuel combusts in the presence of oxygen and forms water vapor and carbon dioxide as products. The enthalpy of this reaction is –2877.5 kJ per mole. Write the correct thermochemical equation for this reaction. What does this equation tell us about the reaction? How is a thermochemical equation different from other chemical equations?
Please help me! It is urgent!!
The thermochemical equation for the combustion of butane is:
C₄H₁₀(g) + 6.5 O₂(g) ⇒ 4 CO₂(g) + 5 H₂O(g) ΔH = -2877.5 kJ
It informs us of the entalphy of the reaction and it includes the states of aggregation.
What is a thermochemical equation?A thermochemical equation is a balanced stoichiometric chemical equation that includes the enthalpy change, ΔH.
Step 1: Write the balanced equation for the complete combustion of butane.C₄H₁₀ + 6.5 O₂ ⇒ 4 CO₂ + 5 H₂O
Step 2: Write the thermochemical equation.To the previous equation, we will add the enthalpy change and the states of agregation.
C₄H₁₀(g) + 6.5 O₂(g) ⇒ 4 CO₂(g) + 5 H₂O(g) ΔH = -2877.5 kJ
The thermochemical equation for the combustion of butane is:
C₄H₁₀(g) + 6.5 O₂(g) ⇒ 4 CO₂(g) + 5 H₂O(g) ΔH = -2877.5 kJ
It informs us of the entalphy of the reaction and it includes the states of aggregation.
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what is The relationship between a carnivore and an herbivore can be stated as
A
parasite and host
B
predator and prey
C
prey and predator
D
scavenger and parasite
The molar mass of sucrose (C12H22O11) is 342. 3 g/mol. A chemist has a 0. 500-mol sample of sucrose. What is the mass, in grams, of this sample? 171 grams 342 grams 500 grams 684 grams.
Mass is the weight of the compound or the molecule in a sample that is given in grams. The mass of sucrose in the sample is 171 gms.
What is mass?The mass of the compound is the product of the molar mass of the compound and the number of moles of the compound in a sample.
Given,
The molar mass (m.w.t) of sucrose = 342.3 g/mol
Number of moles (n) of sucrose = 0.500 moles
The mass of sucrose is calculated as:
[tex]\begin{aligned} \rm mass &= \rm molar\; mass \times moles \\\\&= 342.3 \times 0.500\\\\&= 171.15 \;\rm gm\end{aligned}[/tex]
Therefore. the mass of sucrose in the sample is option A. 171 gms.
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hello people ~
A proton donor is a chemical that
a) protongenic
b) protophilic
c) amphoteric
d) amphiprotic
Answer:
Amphiprotic
Explanation:
These chemicals are too independentThey can either donate or accept a lone pair of protons .So they can act as base and acidCompared to the nucleus 5626fe, what is the density of the nucleus 112 48cd?
For a comparison of the nucleus 5626fe, the density of the nucleus 112 48cd is mathematically given as the same.
n(Cd) / n(Fe)=1
What is the density of the nucleus 112 48cd?Generally, the equation for the density is mathematically given as
d=\frac{A}{4/3}\piR^3
Therefore
n(Cd) / n(Fe) = [A (Cd) / (A Fe) ] * [ R (Fe) / R (Cd)]^3
n(Cd) / n(Fe)= (112 / 56 ) * (1/1.26)3
n(Cd) / n(Fe)=1
In conclusion, The ratio of n(Cd) = n(Fe) is 1, hence same
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Compared to the nucleus ⁵⁶₂₆Fe, the density of the nucleus ¹¹²₄₈Cd is same.
How do we calculate the density of nucleus?Density of any nucleus will be calculated by using the below equation as:
ρ = m/V, where
m = mass of the atom
V = volume = 4/3πR³
For the given question calculation will be proceed as:
n(Cd) / n(Fe) = [m(Cd)/m(Fe)].[R(Fe)/R(Cd)]³
From the given formulas of iron and cadmuim we put values on the above equation then we get,
n(Cd) / n(Fe) = (112 / 56 ) × (1/1.26)3
n(Cd) / n(Fe) = 1
Hence the density of nucleus ¹¹²₄₈Cd is same as of nucleus ⁵⁶₂₆Fe nucleus.
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In a terrarium, the pincushion moss, the echeveria, and the moon cactus make up which of the following? Select all that apply. A. a population B. part of a community C. part of an ecosystem
The pincushion moss, the echeveria, and the moon cactus in a terrarium make up a community.
What is a community of organisms?A community of organisms refers to a group of organisms of different species which are found living together in the same habitat.
Populations of organisms of different species within the same habitat constitute a community.
The pincushion moss, the echeveria, and the moon cactus are all different species found within the same habitat, a terrarium.
Therefore, the different species of organisms in the terrarium make up a community.
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Answer: part of a community and part of an ecosystem
Explanation:
Which describes the enthalpy change associated with an endothermic reaction? *
2 points
ΔH is negative
ΔH is zero
ΔH is positive
Answer:
It is negative because the enthalpy of the products is greater than the enthalpy of the reactants.