Final answer:
To calculate the percent composition of bromine in KBr, find the atomic mass of bromine and potassium, add them to get the formula mass of KBr, and divide the atomic mass of bromine by the total mass, then multiply by 100% to get the percentage.
Explanation:
To calculate the percent composition of bromine in KBr, you need to know the atomic masses of both potassium (K) and bromine (Br). KBr is made up of one potassium atom and one bromine atom. The atomic mass of potassium is approximately 39.10 amu (atomic mass units), and the atomic mass of bromine averages about 79.90 amu, accounting for its natural isotopic abundance.
The formula to find the percent composition is (mass of the element in one mole of the compound/mass of one mole of the compound) × 100%.
The total mass of one mole of KBr is the sum of the mass of potassium and the mass of bromine, which equals 39.10 + 79.90 = 119.00 amu. The percentage of bromine in KBr can be calculated as follows:
([tex]\frac{Mass of bromine}{Total mass of KBr}[/tex]) × 100% = ([tex]\frac{79.90 amu}{ 119.00 amu}[/tex]) × 100% ≈ 67.14%
Therefore, the percent composition of bromine in KBr is approximately 67.14%.
Enzymes are produced only _________________________.
a. outside the active cell
b. in the DNA of the cell
c. within an active cell
d. in another cell and transported
Answer:
c. within an active cell is the correct answer.
Explanation:
Enzymes are produced only within an active cell.
Enzymes are formed from the amino acids.
Enzymes are the proteins, that are produce within the active cell and they speed up the reaction rate that takes place inside the cells. enzymes are produced in ribosomes.
Enzymes help the cells to interact with each other and help in cell growth.
The oxidation numbers of nitrogen in NH4+, NO2, and NaNO3 are, respectively:
-3, +4, +5
+3, +5, +4
+3, +5, -4
-3, -4, +5
The oxidation numbers of nitrogen in NH₄⁺, NO₂, and NaNO₃ are -3, +4, and +5, as determined by balancing the charges of other atoms in the compounds.
The oxidation numbers of nitrogen in NH₄⁺, NO₂, and NaNO₃ can be calculated using some simple rules. In NH₄⁺, nitrogen must balance the charge from the four hydrogen atoms, each having an oxidation number of +1, leading to the oxidation number of nitrogen being -3. For NO₂, oxygen typically has an oxidation number of -2, with two oxygen atoms that would contribute an overall charge of -4, thus nitrogen must have an oxidation number of +4 to balance out and make the molecule neutral. Finally, in NaNO₃, with sodium having an oxidation number of +1, and three oxygen atoms giving a total of -6, nitrogen must have an oxidation number of +5 to balance the overall charge to zero due to the monatomic sodium ion.
Therefore, the respective oxidation numbers of nitrogen in NH₄⁺, NO₂, and NaNO₃ are -3, +4, and +5.
Which change of state is shown in the model?
condensation
deposition
boiling
freezing
[tex]\boxed{\text{Deposition}}[/tex] is shown in the given model.
Further Explanation:
Condensation
The process by which a substance in its gaseous or vapor form is transformed into its liquid form is termed as condensation. It is just the reverse of evaporation. The random motion of gas particles is reduced and they come together to form a liquid. This is done by altering the temperature and pressure of the substance.
Deposition
The phase transition due to which a gas or vapor transforms directly into solid by not going through the liquid phase is termed as deposition. It is a thermodynamic process. This process occurs when water vapors release enough of its thermal energy and get converted into solids directly without passing through the liquid state. It is the opposite of what is done in the sublimation process and is therefore known as desublimation.
Boiling
The phase transition due to which gaseous or vapor state is formed from the liquid state is known as boiling. This takes place when a substance in its liquid state is heated to its boiling point.
Freezing
It is a process in which the substance gets converted from its liquid state to a solid state. It is just the reverse of melting. In this phase transition, heat is released from the substance and the liquid particles come closer to form solid. The formation of ice is an example of freezing.
In the given model, gaseous or vapor state is transformed into a solid state and this phase change occurs in case of deposition. Therefore deposition is shown in the given model.
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Identify the phase change in which crystal lattice is formed: https://brainly.com/question/1503216 The main purpose of conducting experiments: https://brainly.com/question/5096428Answer details:
Grade: Senior School
Chapter: Phase transition
Subject: Chemistry
Keywords: deposition, freezing, boiling, solid, liquid, vapor, condensation, desublimation, thermodynamic process.
What effect does polarity have on solubility of a compound in water?
It took Jackie two hours to mow the lawn. Two weeks later it took her one and one-half hours to mow the lawn. What can be said about the amount of power used by Jackie the second time she mowed the lawn?
Answer: The amount of power used by Jackie will be more the second time.
Explanation: Power can be written as:
[tex]Power=\frac{Work}{Time}[/tex]
As the power and time follow inverse relationship, the amount of power used by Jackie will be less in first case because the time taken is more.
In the second case, the time taken is less than the first case, so the power used will be more.
A Lewis acid is a substance that can _____.
accept a hydrogen ion
donate a pair of electrons
donate a hydrogen ion
accept a pair of electrons
a 1 molal solution of MgCl2 has a higher boiling point than a 1 molal solution of?
1)FeCl2
2)CaCl2
3)BaCl2
4)NaCl
A 1 molal solution of NaCl would have a lower boiling point elevation than a 1 molal solution of MgCl₂, because NaCl dissociates into fewer ions than MgCl₂, resulting in a lower can't Hoff factor.
The question asks which 1 molal solution has a higher boiling point compared to a 1 molal solution of MgCl₂. The boiling point elevation of a solution is affected by the number of solute particles in the solution, which is related to the can't Hoff factor (i), the measure of ion dissociation of a solute. Since MgCl₂, FeCl₂, CaCl₂, and BaCl₂ all dissociate into three ions (1 cation and 2 anions) when dissolved in water, their boiling point elevation would be expected to be similar given equai molal solutions. However, NaCl dissociates into two ions, thus a 1 molal solution of NaCl would have a lower boiling point elevation compared to a 1 molal solution of MgCl₂ due to lower i value.
What is the name of the thermodynamic barrier that must be overcome before products are formed in a spontaneous reaction?
HELP. NO FAKE ANSWERS. I WILL REPORT. I AM CONFUSED AND NEED HELP. FILL IN THE NOT FILLED BOXES POR FAVOR.
Answer:
Baby Shark
Explanation:
Doo doo doo
How far up can a 200 N elevator be lifted with 600 j of energy
To find out how far a 200 N elevator can be lifted with 600 J of energy, the gravitational potential energy formula (Work = mgh) is used to calculate the height by rearranging it to h = W / (mg), yielding the answer.
Explanation:The question concerns the amount of work (energy expenditure) needed to elevate an object against the force of gravity. Using the work-energy principle, we know that work done on an object is equal to the change in its gravitational potential energy, which can be calculated using the formula Work (W) = mgh, where m is mass, g is the acceleration due to gravity (9.8 m/s2), and h is the height. Given an energy of 600 J, we can calculate the height (h) the elevator can be lifted by rearranging the formula: h = W / (mg). With 200 N representing the weight of the elevator (which also equals the mass times the acceleration due to gravity), the mass (m) of the elevator can be determined as m = 200 N / g, and subsequently, the height it can be lifted with 600 J of energy can be calculated.
What chemical property is present in substances that react slowly to oxygen?
a. the ability to rust
b. color
c. melting point
d. the ability to burn?
Answer:
The answer is A
Explanation:
Substances that react slowly to oxygen have the ability to rust. The ability to rust and the ability to burn are both examples of chemical properties that some substances can have.
What molecule is used to capture light energy? view available hint(s) what molecule is used to capture light energy? chlorophyll water carbon dioxide nadph atp?
How do you determine the chemical reactivity for metals using the periodic table?
A 30.5 gram sample of glucose (c6h12o6) contains ________ mol of glucose.
To find the number of moles in a 30.5-gram sample of glucose, calculate its molar mass (180.16 g/mol) and divide the sample mass by this number, resulting in approximately 0.1693 moles of glucose.
To calculate the number of moles of glucose in a 30.5-gram sample, we will use the formula:
moles = mass (g) / molar mass (g/mol)
First, we should determine the molar mass of glucose [tex](C_6H_{12}O_6)[/tex]. The atomic masses of carbon (C), hydrogen (H), and oxygen (O) are roughly 12.01 g/mol, 1.008 g/mol, and 16.00 g/mol, respectively. Therefore, the molar mass of glucose is calculated by summing up the atomic masses of all the atoms in one molecule:
(6 × 12.01 g/mol) for carbon,
(12 × 1.008 g/mol) for hydrogen,
(6 × 16.00 g/mol) for oxygen
This gives us:
(6 × 12.01) + (12 × 1.008) + (6 × 16.00) = 180.16 g/mol
Now, dividing the mass of the glucose sample by the molar mass gives us the number of moles:
30.5 g / 180.16 g/mol = 0.1693 mol
Therefore, a 30.5-gram sample of glucose [tex](C_6H_{12}O_6)[/tex] contains approximately 0.1693 mol of glucose.
In the reaction , Zn + HCl—> ZnCl2 + H2, 25 grams Zn are reacted with 17.5 grams HCl. How many grams of H2 will be produced ?
A. 0.382 g of H2
B. 0.479 g of H2
C. 0.7865 g of H2
D. 0.484 g of H2
0.479 g of hydrogen will be produced if 25 grams Zn are reacted with 17.5 grams HCl.
What is hydrochloric acid?Hydrochloric acid is an aqueous solution of hydrogen gas and chlorine gas.
The reaction is
[tex]\rm Zn + 2 HCl = ZnCl2 + H_2[/tex]
The number of moles present in Zn will be
[tex]\rm \dfrac{25g}{65.38g/mol} = 0.3824 mol[/tex]
The number of moles present in HCl will be
[tex]\rm \dfrac{ 17.5g}{36.46g/mol} = 0.479mol[/tex]
The mass of hydrogen present is [tex]\rm 0.479mol \times 1/2 \times 2g/mol = 0.479g[/tex]
Thus, The correct option is B. 0.479 g.
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Which of the following is true regarding nuclear fission and nuclear fusion?
A. Both of these processes can provide energy.
B. Our sun's heat is an example of both of these processes.
C. Both of these processes are equally complex to control.
D. Nuclear fission involves combining elements, while nuclear fusion involves breaking down elements
The correct answer is:
A. Both of these processes can provide energy
Answer:
A. Both of these processes can provide energy.
Explanation:
J. j. thomson is credited with which discoveries? select all that apply. subatomic particles neutrons isotopes electrons
Express in scientific notation. Remember, M must be a number 1 ≤ M < 10. 18 =
Atoms of elements at the top of a group on the periodic table are smaller than the atoms of elements at the bottom of the group. How does this help explain the difference in the reactivity of metals within a group? The valence electrons of the larger atoms are farther from the nucleus and are easier to remove, so the metals near the top are more reactive than those at the bottom. The valence electrons of the larger atoms are farther from the nucleus and are harder to remove, so the metals near the bottom are more reactive than those at the top. The valence electrons of the larger atoms are farther from the nucleus and are harder to remove, so the metals near the top are more reactive than those at the bottom. The valence electrons of the larger atoms are farther from the nucleus and are easier to remove, so the metals near the bottom are more reactive than those at the top.
Answer:
the answer is D.The valence electrons of the larger atoms are farther from the nucleus and are easier to remove, so the metals near the bottom are more reactive than those at the top.
Explanation:
The valence electrons of the larger atoms are farther from the nucleus and are easier to remove, so the metals near the bottom are more reactive than those at the top. Hence, option D is correct.
What is valence elctron?Valency is the number of bonds an element or an atom can form. Whereas valence electrons are the electrons that take part in chemical bond formation.
Atoms get bigger as you go down a column on the periodic table.
This is because in going down a column you are jumping up to the next
higher main energy level (n) and each energy level is further out from the
nucleus - that is, a bigger atomic radius.
Atoms get smaller as you go across a row from left to right.
Hence, option D is correct.
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"identify the part of the atom that most determines the chemical reactivity of the atom"
Calculate the ph of 0.200 mol dm–3 ethanoic acid (pka = 4.76).
The pH of the 0.200 mol dm⁻³ ethanoic acid solution is 4.76. The ethanoic acid is represented by (CH₃COOH).
To calculate the pH of a solution of ethanoic acid, you can use the formula:
pH = pKa + log([A-]/[HA])
Since ethanoic acid (CH₃COOH) is a weak acid, it partially dissociates in water to form acetate ions (CH₃COO⁻) and hydrogen ions (H⁺).
The dissociation equation is:
CH3COOH ⇌ CH3COO⁻ + H⁺
At equilibrium, the concentration of the acetate ion will be equal to the concentration of the undissociated acid, so [A-] = [HA].
Now, substituting these values into the pH formula:
pH = 4.76 + log([A-]/[HA])
= 4.76 + log(0.200/0.200)
= 4.76 + log(1)
= 4.76 + 0
= 4.76
Therefore, the pH of the 0.200 mol dm⁻³ ethanoic acid solution is 4.76.
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Electronegativity tends to increase from left to right across a row, because A. the number of energy levels increases. B. the shielding effect increases. C. the attraction between the nucleus and the valence electrons increases. D. the valence electrons are located farther away from the nucleus.
Answer: C. the attraction between the nucleus and the valence electrons increases.
Explanation: Electronegativity is the tendency of the element to attract the shared pair of electrons towards itself.
Electronegativity of the elements increase across a period as the electrons get added to the same shell and the nuclear charge increases, the valence electrons become near to nucleus and thus the tendency of the elements to attract the shared pair of electrons itself increases.
Electronegativity of the elements decrease down a group as the electrons get added to new shell and the nuclear charge increases, but the effect of addition of shells is more dominant and thus the size increases and the tendency of the elements to attract the shared pair of electrons itself decreases.
How many grams of h 2 are needed to produce 12.95 g of n h 3 ?
Answer is: mass of hydrogen is 2.28 grams.
Balanced chemical reaction: 3H₂ + N₂ → 2NH₃.
m(NH₃) = 12.95 g; mass of ammonia.
n(NH₃) = m(NH₃) ÷ M(NH₃).
n(NH₃) = 12.95 g ÷ 17.03 g/mol.
n(NH₃) = 0.76 mol; amount of ammonia.
From chemical reaction: n(H₂) : n(NH₃) = 3 : 2.
n(H₂) = 3 · 0.76 mol ÷ 2.
n(H₂) = 1.14 mol; amount of hydrogen.
m(H₂) = 1.14 mol · 2 g/mol.
m(H₂) = 2.28 g; mass of hydrogen.
Which of these statements describes a limitation of the Treaty on Plant Genetic Resources?
A. It does not involve other countries.
B. It does not allow the use of seed banks.
C. It does not address threats to genetic diversity.
D. It does not address the loss of biodiversity.
Answer:
C. It does not address threats to genetic diversity.
Another APEX Answer:
It ignores threats to genetic diversity.
Answer:
Option D
Explanation:
The Treaty on Plant Genetic Resources also known as International seed treaty was passed in order to guarantee food security, sustainable use of world’s genetic resource along with preserving farmers right. Some of the limitations of this treaty are
a) Limited interventions to preserve the biodiversity
b) Limited extent of intellectual property rights on genetic resources
c) Unclear extent of freedom to framers to use, exchange, sell and breed seeds
Hence, option D is correct
Given: 2AgNO3 + NiCl2 -> 2AgCl + Ni(NO3)2
Determine the limiting reactant when 0.847 grams of silver nitrate is reacted with 0.650 grams of nickel(II) chloride?
It took 4.5 minutes for 1.0 l helium to effuse through a porous barrier. how long will it take for 1.0 l cl2 gas to effuse under identical conditions?
Using Graham's Law of Effusion, we can determine that it takes approximately 4.2 hours for 1.0 l of Cl2 gas to effuse under the same conditions as helium, due to Cl2's higher molar mass.
Explanation:This question can be answered using Graham's Law of Effusion, which states that the rate of effusion of a gas is inversely proportional to the square root of its molar mass. This means that lighter gases effuse faster than heavier ones. Effusion is the process by which a gas escapes through a pinhole into a vacuum.
The molar mass of helium (He) is approximately 4 grams/mole, while the molar mass of chlorine (Cl2) is approximately 70 grams/mole. If it took 4.5 minutes for 1.0 l helium to effuse, then we can use Graham's law to calculate the time it will take for 1.0 l of Cl2 gas to effuse under the same conditions. It takes about 4.2 hours for 1.0 l of Cl2 gas to effuse under the same conditions as helium.
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Which choice is an example of a consumer? Question 9 options: tree fungi bee sun
A company sells a natural medicine with plant ingredients to help treat dementia, a disease in which people have a hard time remembering things. The natural ingredients in the medicine are most likely from which type of plant?
-gnetophyte
-conifer
-ginkgo
-cycad
Answer:
C. Ginko
Explanation:
The type of plant should be ginkgo.
The following information should be considered:
Ginkgo should considered as the large tree along with fan-shaped leaves. The leaves are involved in supplements and considered by mouth for memory problems. In this, the natural ingredients in the medicine should be used.learn more: https://brainly.com/question/2386757?referrer=searchResults
Bruce left some butter out in his kitchen. Bright sunlight came in through the window and melted the butter. Heat energy from the sun is called
Answer:
Solar radiation
Explanation:
In general there are three forms of energy: heat, light and sound. Energy transfer takes place as energy moves from one object to another in a certain medium or in vacuum.
The heat energy or the electromagnetic energy from sun strikes the earth surface in the form of radiation. This is also called solar energy or solar radiation.
PUTTING MAX POINTS
Which statement about the following reaction is correct?
CH4 (g) + 2O2 (g) yields CO2 (g) + 2H2O(l) deltaH = -890 kJ
reacting one mole of oxygen (O2) absorbs 445 kJ of energy
reacting one mole of oxygen (O2) releases 445 kJ of energy
reacting one mole of methane (CH4) absorbs 890 kJ of energy
reacting two moles of methane (CH4) releases 890 kJ of energy
the first one is correct because one mole of oxygen is half of 2O2 so it is half of the energy