The enthalpy of the reaction when 0.384 g of sodium metal is added to an excess of hydrochloric acid and 3990 J of heat is produced is 266 KJ.
The balanced chemical equation of reaction is -
2 Na(s) + 2 HCl(aq) ⟶ 2 NaCl(aq) + H₂(g)
We know that,
weight of sodium metal is 0.384 g
Molar mass of Na is 23 g/mol
we will calculate the number of moles,
Number of moles = Given mass
Molar mass
Moles of Na = 0.348 g = 0.015 mol
23 g/mol
We will calculate the energy in 1 mole of sodium metal
In 0.015 moles of sodium metal, 3990 J of energy is produced.
so, in 1 mole of sodium metal, 3990 J of energy is produced
0.015
In 1 mole, 266000 J of energy is produced.
1 J = 0.001 KJ
266000 J = 266 KJ
The enthalpy of the reaction will be 266 KJ.
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reducing agent in the following reaction 4Al+ 3O2 = 2Al2O3
Answer: O2 is the reducing agent
Explanation: When you are adding oxygen, you are oxidizing. So O2 is the reducing agent because Aluminum loses electrons and becomes positive in charge and O2 gains electrons and becomes negative in charge. Aluminum is oxidized and oxygen is reduced, therefore the oxygen is the reducing agent. Remember oxidation cannot occur in isolation. There is another process going on when something is oxidized and that process is reduction.
i need help with chemistry equation
Mass of dichloromethane is 324.9g
We can define mass as the measure of the amount of matter in a body
Here given reaction is
CH₄ + CCl₄ → 2CH₂Cl₂
So the limiting reactant is the reactant that produced the leadt amount of product and the molar mass of methane is 16.042g/mol and the number of mole of methane is
n = 30.7/16.042
n = 1.913 mol
And the amount of dichloromethane that can be produced is
n = 1.913 mol ×2/1 = 3.826 mol
So, molar mass of dichloromethane is 84.9325
3.826 mol × 84.9325 = 324.9g
So, mass of dichloromethane is 324.9g
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A pebble is dropped from rest into a deep well. At time ts later it splashes into the water at the bottom of the well. Sound travels at 340 ms¹ and is heard at the top of the well 5s after the pebble was released. Find the depth of the well.
Answer:
look that might be answer
Explanation:
John measured the mass of copper sulfate salt to be 5.9 g. The actual mass was 6.0 g. What is his percent error? Show all work.
A function of the plasma membrane includes _______.
1. steroid synthesis
2. phospholipid synthesis
3. cell mitosis
4. letting water, certain ions and substrates into the cell
5. protein synthesis
A function of the plasma membrane includes letting water, certain ions and substrates into the cell (Option 4).
What is the plasma membrane?The plasma membrane is the main selective barrier that allows the interchange of nutrients and byproducts of the cell with its surrounding media (i.e., its external environment). The cell membrane allows the passage of substances such as water or ions by using protein channels or also the movement through active transport, which requires energy to proceed.
Therefore, we can conclude that the plasma membrane allows the passage of water and ions inside the cell.
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I need help with this homework assignment problem
Answer:
A. Ar+2
B. 18
C. 0
Explanation:
There are total of 2 + 2 + 6 + 2 + 4 = 16 electrons
since the cation is +2, it's neutral state should be 16 + 2 = 18
A. The ion is Ar+2
B. 18
C. Since 3p => 4s => 3d, there is no 3d
Zn + HC->> ZnCl₂ + H₂
what is balanced
The balanced equation is:
Zn + 2HCl ---> ZnCl2 + H2
Feedback can either cause a change in the system or keep it stable. Melting glaciers are an example of positive feedback.
Why is this considered positive feedback?
Feedback can either cause a change in the system or keep it stable. Melting glaciers are an example of positive feedback.
This is considered a positive feedback because melting of the glaciers would let the air and land of the surrounding get warmer which would cause the glaciers to melt faster.
A positive feedback causes a system to remain stable or causes a change in the system.Global warming is melting ice, thus it amplifies the loss of ice. It is an important feedback called ice albedo feedback.
The increased temperature of ice leads to a positive feedback. It is an increased internal friction heating (strain). This is a positive feedback because it leads to further heating of the ice from the inner side of the ice sheet.
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How many moles of sulfur present in a sample containing 7.65 x 1022
atoms?
Answer: 1.27 mol Sulfur
Explanation: For every element, one mole of it contains 6.02x10^22 atoms (Avogradro's Number). So you just divide the original amount by Avogadro's Number to get 1.27 moles.
The diagram below represents a chemical cell at 298 K. When the switch is closed, electrons flow fromCaptionless Image(1) Al³⁺(aq) to Ni²⁺(aq)(2) Ni²⁺(aq) to Al³⁺(aq)(3) Al(s) to Ni(s)(4) Ni(s) to Al(s)
INFORMATION:
We know that:
- the diagram represents a chemical cell at 298 K
And we must determine how is the flow of electrons when the switch is closed
STEP BY STEP EXPLANATION:
To determine it, we need to know that the flow of electron will be from the particles undergo oxidation to particles undergo reduction.
Analyzing the equation, we can see that Al particles undergo oxidation and Ni particles undergo reduction
Then, electrons will flow from Al(s) to Ni(s)
ANSWER:
(3) Al(s) to Ni(s)
heeeelp
Plants do not have bones that provide them with structure and support, they have
_____.
tubes made of cellulose
cytoplasm
an exoskeleton
muscles
Which of the following is a tendon and not a ligament?
The anterior cruciate ligament (ACL) which is located toward the front of the knee and controls forward movement and rotation of the surrounding bones.
The ulnar collateral ligaments which runs along the inner side of the elbow connecting bones
The anterior talofibular ligament which connects the talus (a bone in the foot) to the fibula (the outer bone in the leg).
The Achilles which connects calf muscles to your heel bone
Which type of organisms have an exoskeleton?
mammals
crustacean
worms
plants
All organisms have either an endoskeleton or an exoskeleton.
True
False
Plants do not have bones that provide them with structure and support, they have tubes made of cellulose; option A.
The Achilles is a tendon and not a ligament; option D
The type of organism that has an exoskeleton is crustacean; option C.
All organisms have either an endoskeleton or an exoskeleton is False because plants do not have either an endoskeleton or an exoskeleton.
What are the structures for support found in plants?
Plants unlike animals do not have skeletons that provide shape and support to them.
Instead, plants have sclerenchyma cell walls which are composed of lignin and extra cellulose. These provide support and shape to plants.
Ligaments are structures found in joints and other parts of the body that provide support to bones, joints, organs, and other structures.
Ligaments in the body include;
The anterior cruciate ligament (ACL)The ulnar collateral ligaments The anterior talofibular ligamentExoskeletons are found in small animals and insects. For example, crustaceans have an exoskeleton.
Other larger organisms such as mammals. have an endoskeleton.
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balanced net ionic equation Pb2+(aq) + S2−(aq) → PbS(s)
The balanced net ionic equation for the reaction is given below:
Pb²⁺ (aq) + S²⁻ (aq) → PbS (s)
What are ionic equations?Ionic equations are equations that show the ionic species involved i a reaction.
The ionic species in the reaction may undergo reduction or oxidation.
Therefore, ionic equations are usually redox reactions.
In balancing ionic equations, the atoms and the electrons involved in the reaction are balanced on both sides.
Considering the given ionic equation:
Pb²⁺ (aq) + S²⁻ (aq) → PbS (s)
The given equation above is a balanced net ionic equation both in electron transfer as well as in the number of atoms.
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I need help please, can't figure this one out.
The relative atomic mass of the rubidium atom could be calculated from the data provided as 85.46.
What is an isotope?When we talk about an isotope, we are referring to the idea that we could have tow or more atoms of the same element that have the same atomic number but do not have the same mass number. Given that the atomic number is the number of protons, it then follows that the two elements as we know them does differ only in the number of the neutrons that they have. The atoms that we have thus described in the several lines above are other wise called the isotopes of the element. We have in the image of the question a clear example of what an isotope is and we now want to find the relative atomic mass of Rubidium.
The relative atomic mass can be obtained from the use of the formula;
(84.9118 * 72.2/100) + (86.9092 * 27.8/100)
= (61.30 + 24.16)
= 85.46
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The table shows the masses of four blocks which have the same volume but are made of different materials
The correct answer is gold block has the maximum density.
What is the relation between Mass, Volume and Density?
Three of an object's most fundamental characteristics are mass, volume, and density. Volume indicates how large something is, mass indicates how heavy it is, and density is determined by dividing mass by volume. Although you frequently deal with the concepts of mass and volume, the concept of density is less clear-cut and requires careful consideration. Density is useful, though, once you get the hang of it.
Density = mass / volume
So as per given data as the volume is same for all material then we can consider only mass and density
Given, Volume remains constant
So, as mass and density are Directly proportional, it means whose mass is larger than its density will be larger or denser.
From given data Gold has larger mass then its density is larger.
Hence, Gold block has the maximum density
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what is the formula for calcium nitrate
Answer:Ca(No3)2
Explanation:
A silver ring reacts with compounds containing sulfur in the air to form silver sulfide, a black substance that makes up the tarnish on the surface of silver objects. To remove the tarnish from the ring, students placed it in a pan lined with aluminum foil and added hot water. Baking soda was added to the hot water and stirred. Students made observations about the process.
Which observation of this process provides evidence of a chemical reaction?
The observation of this process that provides evidence of a chemical reaction is "The liquid solution changed color" Option B
This is further explained below.
What is a chemical reaction?Generally, A chemical reaction is a process in which one or more compounds, referred to as the reactants, are changed into one or more new substances, referred to as the products.
Either the chemical components or the chemical compounds make up a substance.
During a chemical reaction, the individual atoms that make up the reactants are rearranged, which results in the production of new substances.
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CQ
A silver ring reacts with compounds containing sulfur in the air to form silver sulfide, a black substance that makes up the tarnish on the surface of silver objects. To remove that tarnish from the ring, students placed it in a pan lined with aluminum foil and added hot water. Baking soda was added to the hot water and stirred. Students made observations about the process. Which observation of this process provides evidence of a chemical reaction? *
A- Hot water heated the aluminum foil
B- The liquid solution changed color
C- The pan was lined with aluminum foil
D- The hot water cooled
Classify each of the following as exothermic or endothermic:
a. C3H8(g) + 5O2(g) -->3CO2(g) + 4H2O(g) + 2220 kJ
b. 2Na(s) + Cl2(g) --> 2NaCl(s) + 819 kJ
c. PCl5(g) + 67 kJ --> PCl3(g) + Cl2(g)
Calculate the energy, in joules, required to ionize a hydrogen atom when its electron is initially in the n=3 energy level. The energy needed to ionize a ground-state hydrogen atom is 2.18 x 10-18 J. The energy for ionization from the n = 3 state is ______J
The energy required to ionize a hydrogen atom from the n = 3 energy level is 2.422 x 10 ⁻¹⁹J.
Explanation:The amount of energy required to remove an electron from an atom from its excited state to a ground state is referred to as the energy required for ionization.The energy of ionization is determined by two factors: the force of attraction between electrons and the nucleus. The repulsion force between electrons.Determine the number of electrons in the atom. Unless the atom has already lost some electrons, this number is the same as Z. Calculate the ionization energy of a one-electron atom in electron volts by squaring Z and then multiplying the result by 13.6.in the given question ,
The ionization energy can be expressed as follows:
E = 2.18 x 10 ⁻¹⁸ (1/n₁² - 1/∞²)
given , n = 3
E = 2.18 x 10 ⁻¹⁸ (1/3² - 1/∞²)
E = (2.18 x 10 ⁻¹⁸) / 9
E = 2.422 x 10 ⁻¹⁹
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Isotopes of an element have different numbers of _____.
A protons
B neutrons
C atoms
D electrons
I believe the answer is B, neutrons
which of the following reactions is balanced and shows incomplete combustion?
The reaction that is chemically balanced and shows complete combustion is [tex]C_3 H_8 + 5 O_2 -- > 3 CO_2 + 4 H_2 O[/tex], Option B.
What is a balanced equation?A balanced equation is an equation that obeys the law of conservation of atoms.
According to this law, atoms cannot be created and cannot be destroyed during the course of chemical reactions. The atoms can, however, be converted into different forms.
Thus, a balanced equation must have an equal number of participating atoms on both the reactant and product sides of the equation.
Also, a complete combustion reaction must produce carbon dioxide and water. Not carbon monoxide.
Therefore, the equation that fulfills the two conditions is[tex]C_3 H_8 + 5 O_2 -- > 3 CO_2 + 4 H_2 O[/tex]
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Answer:
C
Explanation:
I got it right
17. Upon heating 1 dm³ of a monoatomic gas, Y, it
combines with 1.5dm³ of oxygen to form an oxide. The
empirical formula of the oxide is
According to the given statement The empirical formula of the oxide is YO3.
What exactly is an empirical formula?Chemical formulae for compounds that simply specify the proportions of the elements they include rather than the exact number or arrangement of atoms are known as empirical formulas. The component in the compound with the lowest whole lot would be this one.
How can one find empirical formula?By: Calculating the number of moles of each element from its mass, empirical formulas are generated using empirically measured element masses. Obtaining subscripts for a possible empirical formula by dividing the molar amount of each element by its smallest molar amount.
Briefing:Since volume is represented as moles
Y 0
1 1.5
Y+1.5O2 = YO3.
YO3 - the empirical formula.
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Name of the anion in the ionic compound, Mg(ClO4)2, NH4NO3, Cu(CH3CO2)2, K2SO3
In given ionic compound, Mg(ClO4)2 anion is ClO4⁻, NH4NO³ anion is (NO3)⁻, Cu(CH3CO2)² anion is [CH3COO]⁻, K2SO³ anion is SO3²⁻.
What is a anion and cation?Positively charged ions are known as cations. Ions with negative charges are referred to as anions. A charged molecule or an atom is an ion. A balanced atom will change into a positively charged cation if one or more of its electrons are lost.
When non-metals gain electrons, they are created. They don't lose any protons and gain one or more electrons. They get a negative net charge as a result. The anions iodide (I-), chloride (Cl-), and hydroxide are some examples (OH–).
What are the uses of an anion?Anion exchange device applications. They lower the levels of nitrate, arsenic, and sulfate in water. Point-of-use units only filter harmful chemicals out of drinking and cooking water and are connected to a single tap.
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**NEED ANSWER ASAP, H.W QUESTION**
If the proton proton chain produces gamma ray photons, why are the majority of photons we observe from the sun at visible wavelengths?
In a proton-proton chain, four hydrogen nuclei (protons) are combined to form one helium nucleus; 0.7 percent of the original mass is lost mainly by conversion into heat energy, but some energy escapes in the form of neutrinos (ν).
Explanation:
Which of the following is characteristic of group 14 elements
The characteristic of group 14 elements is that they have four valence electrons in their outermost shell.
What is an Element?This is referred to as a substance which can't be broken down into simpler substances through as chemical reaction and examples include hydrogen, calcium etc.
These elements are arranged into different groups and periods on a periodic table according to their similarities. For example group 14 elements have four valence electrons which they need to complete in other to achieve a stable configuration.
Example of group 14 elements are carbon,silicon, tin etc which form covalent bonds with other elements in a reaction so as to ensure that that both become stable and is therefore the reason why it was chosen as the most appropriate choice.
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Round 2,509 to 3 sig figs
2509 in 3 significant figures is 2510.
What is significant figures?Significant figures is a digit that is meaningful with respect to the precision of a measurement.
Significant figures are the number of digits in a value, often a measurement, that contribute to the degree of accuracy of the value.
We can identify the number of significant digits by counting all the values starting from the 1st non-zero digit located on the left. For example, 12.45 has four significant digits.
According to this question, 2509 contains 4 significant figures.
2509 is rounded to significant figures as follows:
rounded to 3 sig figs is 2510to 2 sig figs is 2500to 1 sig figs is 3000To count the number of sig figs in 2509, count all 4 digits since it has no insignificant digits.
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HELP ME OUT PLEASE!!!!!
Which type of energy is stored energy?
O kinetic
O mechanical
O potential
O chemical
Answer: Potential energy.
Explanation: Potential energy is stored energy and the energy of position.
Iodine pentafluoride gas is formed by the balanced chemical reaction shown below. How many liters of iodine
pentafluoride can be formed at STP from the reaction of 0.25 L of fluorine gas at STP with excess iodine?
12 (s) + 5 F2 (g) → 2 IF2 (g)
Liters of iodine pentafluoride can be formed at STP from the reaction of 0.25L of fluorine gas at STP with excess iodine is 0.1 L
The balanced chemical equation is given as:
I₂(g) + 5F₂(g) ------> 2IF₂(g)
1mole 5 mole 2 mole
1 L 5 L 2 L
here , 1 L of I₂ react with 5 L of F₂ to form 2L IF₂
so, 0.25 L react with = 0.25 / 5 = 0.05 L F₂
therefore, iodine pentafluoride gas IF₂ formed = 0.05 × 2 L
= 0.1 L
Thus, Iodine pentafluoride gas is formed. Liters of iodine pentafluoride can be formed at STP from the reaction of 0.25L of fluorine gas at STP with excess iodine is 0.1 L.
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If you have 8.51x10-3 g of O2, and excess ZnS, how many moles of ZnO can you form?
Molar mass O2: 31.998 g/mol
If you have 8.51x10-3 g of O₂, and excess ZnS, moles of ZnO form is 0.174×10⁻³ moles.
The balanced equation is given as :
2ZnS + 3O₂ ------> 2ZnO + 2SO₂
number of moles of O₂ = mass / molar mass
= 8.51 × 10⁻³ g / 31.998 g/mol
= 0.265× 10⁻³ moles
now, 3 moles of O₂ form 2 moles of ZnO
0.265× 10⁻³ moles of O₂ form( 2/3) × 0.265× 10⁻³ = 0.174×10⁻³ moles
The number of moles of ZnO is 0.174×10⁻³ moles
Thus, If you have 8.51x10-3 g of O₂, and excess ZnS, moles of ZnO form is 0.174×10⁻³ moles.
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Suppose you identify a new element, Pivotium. Pivotium has two isotopes: Pivotium-423 and Pivotium-417. In the mixture, 22% of the mixture is Pivotium-423; the rest of the mixture is Pivotium-417.
What is the relative atomic mass for Pivotium?
Considering the definition of atomic mass, isotopes and atomic mass of an element, the relative atomic mass for pivotium is 418.32 amu.
Definition of isotopeThe isotopes of an element are those different atoms that make up an element, that is, their atomic numbers are the same, but the number of neutrons is different.
Definition of atomic massThe atomic mass of an element is the weighted average mass of its natural isotopes, taking into account the relative abundance of each of them.
Atomic mass of the element in this caseIn this case, you know:
Pivotium-423 has an atomic mass of 423 amu and a percent natural abundance of 22%. Pivotium-417 has an atomic mass of 417 amu and a percent natural abundance of 78% (because both isotopes have an abundance of 100%)The average mass of pivotium can be calculated as:
average mass of pivotium= 423 amu×0.22 + 417 amu×0.78
average mass of pivotium= 418.32 amu
Finally, the atomic mass of the pivotium is 418.32 amu.
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Express the answer to the following calculation with the correct number of significant figures.
-Don't put it into Scientific notation.
Type in a unit - use the symbol/abbreviation (g, not grams)
147.6mm − 0.82mm = _____ in units of _____
The difference as required in the question to the correct number of significant figures is 147 in units of millimeter.
What is the correct number of significant figures?Let us take note of the fact that the term significant figures has to do with the number of figures that could be assigned a place value. This is the number of figures that we could be able to give the corresponding value.
Now we can see that one of the numbers have four significant figures and the other number has only about three significant figures. The result that we obtain must be such that has three significant figures.
It the follows that the result of the computation is; 147.6 - 0.82 = 147 in units of millimeter.
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