Answer: 78.919 amu
Explanation:
If the natural abundance of Br-81 is 49.310%, then the natural abundance of Br-79 must be 100%-49.310%=50.690%
Substituting into the atomic mass formula,
[tex]79.904=(0.49310)(80.9163)+(0.50690)(x)\\79.904=39.89982753+(0.50690)(x)\\40.00417247=(0.50690)(x)\\x=\frac{40.00417247}{0.50690}=\boxed{78.919 \text{ amu}}[/tex]
What is the difference between, Flame tests and Flame emission spectroscopy?
Answer:
Flame testing is an analytical technique where a sample is applied to a flame, and the characteristic emission spectrum is used to identify different elements.
Answer:
Flame testing is an analytical technique where a sample is applied to a flame, and the characteristic emission spectrum is used to identify different elements. When this technique is used to identify metal species, it is called metal flame emission testing while Flame emission spectrophotometry is based on the characteristic emission of light by atoms of many metallic elements when given sufficient energy, such as that supplied by a hot flame.
What happens when less energy is entering than exiting?
Answer:
If there is a decrease in the amount of carbon dioxide or methane, the amount of energy leaving the Earth system increases, so less energy enters than exits. When less energy enters than exits, Earth's surface absorbs less energy.
Explanation:
A catalyst ______. (select all that apply.) multiple select question. is depleted in a chemical reaction undergoes no permanent change during a reaction does not participate in a chemical reaction
The statements that are true regarding a catalyst are as follows:
It undergoes no permanent change during a reaction
It does not participate in a chemical reaction
What is a catalyst?
A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process.
A catalyst increases the rate at which a chemical reaction occurs by decreasing the activation energy of the reaction.
Since a catalyst is not used up in the reaction, the following statement applies:
It undergoes no permanent change during a reaction
It does not participate in a chemical reaction
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Identify the products of the reaction between 2KOH and H₂SO4- OH.
Answer:
The reaction is H2SO4 + 2KOH = K2SO4 + 2H2O
It resembles a double displacement reaction.
Notice how it is balanced so that there are the same number of each type of atom on both sides of the reaction.
The potassium sulfate will ionize into K+ ions and SO4-- ions, but the formula is usually written as above.
What property of a substance does its specific heat capacity describe?
OA. How much heat is needed to melt it
OB. How much kinetic energy it contains
O C. How much heat it takes to raise the temperature
D. How good an insulator it is
Answer: How much heat it takes to raise the temperature
Specific heat describes how much heat a substance takes to raise the temperature. Hence, Option (c) is correct
What is Specific Heat ?
Specific heat capacity is the amount of heat energy required to raise the temperature of a substance per unit of mass.
The specific heat capacity of a material is a physical property.
It is also an example of an extensive property since its value is proportional to the size of the system being examined.
Specific heat describes how much heat a substance takes to raise the temperature. Hence, Option (c) is correct
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If someone asked you to mix up a bag of ringers solution with 150 meq/l of na , 10 meq/l of k , 8 meq/l of ca2 , and 197 meq/l of mg2-, how many grams of mg2- would you add to the mixture?
The normality is the ratio of the equivalent to the volume of the solvent. To the mixture, 1.182 gms of magnesium should be added.
What is Normality?Normality (N) is the grams or moles of solute per liter of solution.
Magnesium has 2 valence electrons in the outermost shell so,
1 mEq of Mg⁻² ions = atomic number of Mg ÷ valence electron
= 12 ÷ 2
= 6 mg
In a liter solution having 197 meq/l of Mg⁻²:
197 meq/l of Mg⁻² × 6 = 1182 mg
Therefore, 1.182 gms of magnesium ions should be added to the mixture.
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The isotope sodium-24 has a half-life of 15 hours. Starting with 22 grams, how much remains in 45 hours
The amount, in grams, that will remain of the isotope will be 2.75 grams
Half-lifeIt is the time it takes for a given amount of radioactive substance to decay into half of its original amount.
The half-life is 15 hours. This means that the amount is halved every 15 hours.
If the starting amount is 22 grams, it will become 11 grams (22/2) after the first 15 hours. The 11 grams will become 5.5 grams (11/2) after another 15 hours, making 30 hours.
The 55.5 grams remaining will become 2.75 grams (5.5/2) if another 15 hours should pass, making a total of 45 hours that have passed.
Thus, only 2.75 grams of the isotope will remain in 45 hours.
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Based on the shapes of the water drops in part D, how does the attractive force between water and wax compare to the attractive force between water and glass?
Answer:
Because the cohesive forces inside the droplets are stronger than the adhesive forces between both the drops and the wax, water does not penetrate waxed surfaces. Because the adhesive forces between the liquid and the glass are stronger than the cohesive forces inside the water, water wets glass and spreads out across it.
Explanation:
EDMENTUM
When the temperature of a liquid is increased a little,
what happens to its particles?
Answer:
The particles moves faster thus Expanding the liquid
How many milliliters of a stock solution of 2.50 M SrCl2 would you need to dilute to make 50.0 mL of 1.00 M SrCl2?
Answer:
20 ml
Explanation:
2.5 M x = 1 M * 50
x = 20 ml
Hello Brainly! Please Help! Thank You! (The Directions are the Red Text)
Answer:
ok so which answer do you want if you want all then here's this
Explanation:
you should remember that you aren't the only on who dosent know the answers because I don't so ask a parent
Match the following
1. coefficient
2. law of conservation of mass
3. product
4. reactant
the number written in front of a
chemical symbol in an equation
principle that during a chemical
reaction the total mass of the system is
unchanged
the substance made in a chemical
reaction
the starting material in a chemical
reaction
The order would be coefficient, law of conservation of mass, products, and reactants respectively.
Word matchingThe number written in front of a chemical symbol in an equation is called a coefficient.
The total mass of a system being unchanged is known as the law of conservation of mass
The substances made in chemical reactions are called products.
The starting materials in chemical reactions are called reactants.
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What causes lines in a line spectrum?
A. Transitions that don't happen to an electron
B. Wavelengths of absorbed or emitted photons
C. Quantum numbers associated with an electron
D. Edges on the prism used to separate wavelengths
Wavelengths of absorbed or emitted photons causes lines in a line spectrum.
What causes lines in a line spectrum?Spectral lines are produced by transitions of electrons within atoms. As the electrons move closer or farther from the nucleus of an atom, energy is released in the form of light is emitted.
So we can conclude that Wavelengths of absorbed or emitted photons causes lines in a line spectrum.
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You can make a solution (solid solute) more concentrated by
adding more solute
O increasing the pressure
adding more water
adding more solvent
Answer:
increasing the pressure
Explanation:
You can make a solution more concentrated by increasing the pressure.
The following diagram represents what type of reaction?
The type of reaction represented by the diagram is (C). Fission
Meaning of Nuclear FissionNuclear fission can be defined as a reaction in which the nucleus of an atom splits or breaks into two or more smaller portions of nuclei.
Nuclear fission is so important and is often seen or encountered when dealing with elements with high nuclear properties.
In conclusion, the type of reaction represented by the diagram is Fission
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Predict the product of the reaction of cyclopentanone with ethylene glycol, p−toluenesulfonic acid, and benzene
The answer to the product of the reaction of cyclopentanone with ethylene glycol, p−toluenesulfonic acid, and benzene is attached in the figure.
What is a reaction ?A chemical process in which substances act mutually on each other and are changed into different substances, or one substance changes into other substances is called a reaction.
Chemical reactions are an integral part of technology, of culture, and indeed of life itself.
The Product obtained of the reaction of cyclopentanone with ethylene glycol, p−toluenesulfonic acid, and benzene is attached in the figure .
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1CO₂ (g) + 1C (s) → 2CO (g)
Keq =
Answer:
the equation is balanced
Newman projections are given for two of the conformers of 2-methylbutane, drawn as viewed down the C2-C3 bond. In A the _____ strain is at a maximum due to the eclipsing of bonds. In B this strain is minimized but there is still _____ strain due to the proximity of the bulky CH3 groups that are _____ to each other. Multiple choice question.
The Newman projection gives the view of the molecule. In molecule A the torsional strain and in B steric strain are present because of the gauche methyl group.
What is a torsional strain?The Newman projection depicts the molecules in the head-on view and uses the letters and the lines to represent the molecule. The torsional strain is because of the molecule's resistance to the twisting.
The steric strain is the Vander wall strain that is due to the forced interaction of the molecules separated by covalent bonds resulting in molecular potential energy.
The diagram for the question is attached below.
Therefore, the correct blanks are torsional, steric, and gauche.
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HELP ASAP PLEASE
The primary cause of water pollution is:
Answer:
the aNSWRER TOP UR QUESTION IS THAT I NMEED TO ANSWER THIS SO I DONT HAVE TO WQATCH ADS LOL
Explanation:
DSADSDASDASDASDSDSDSDSDS and i knowq chem is bio chwem is
Determine the empirical formula of a compound containing 40. 6 grams of carbon, 5. 1 grams of hydrogen, and 54. 2 grams of oxygen.
in an experiment, the molar mass of the compound was determined to be 118. 084 g/mol. what is the molecular formula of the compound?
for both questions, show your work or explain how you determined the formulas by giving specific values used in calculations
The empirical formula is C₂H₃O₂
What is Empirical formula of a compound ?The empirical formula is the simplest whole number ratio of elements present in a compound.
The total molar mass of the compound is 118.084 g/mol.
mass of Carbon present = 40.6
mass of Hydrogen present = 5.1 grams
mass of Oxygen present = 2 grams
Moles of C = 40.6/12 = 3.38
Moles of H = 5.1/1.008 = 5
Moles of Oxygen = 54.2/15.999 = 3.38
Ratio of Moles of C to Oxygen is 1 : 1
Ratio of Moles of C to H is 1/1.5
Multiplying each mole fraction by 2
The empirical formula is C₂H₃O₂
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A gas at STP is heated to 35 degrees
C. What is the new pressure of the gas?
A gas at STP is heated to 35 degree C. The new pressure will be 2.41 atm.
What is Gay-Lussac law?The pressure of the mass of the gas is directly proportional; to the temperature of the gas.
[tex]\dfrac{P_1 }{T_1} =\dfrac{P_2}{T_2}[/tex]
Converting the temperature into kelvin
The initial temperature = 35 °C = 35 + 273 K= 308 K
The final temperature = 50 °C =50 + 273 K = 323 K
Initial pressure = 2.3 atm
Final pressure ?
Putting the values in the equation
[tex]\dfrac{P_1 }{T_1} =\dfrac{P_2}{T_2}\\\\\\{P_2 = \dfrac{P_1 \times T_2}{T_1} \\\\\\\\\\{P_2 = \dfrac{2.3 \times 323 }{308} = 2.41 atm.[/tex]
Thus, the new pressure will be 2.41 atm.
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Explain the three ways you can accelerate a golf cart?
Answer:
Pedal, Pushing, and also launching it off a cliff with a catapult
Explanation:
I know nothing
At constant pressure, the volume of a gas is directly proportional to temperature as measured on the __ temperature scale.
At constant pressure, the volume of a gas is directly proportional to temperature as measured on the kelvin temperature scale.
What is Temperature?This is defined as the degree of hotness or coldness of a substance and is influenced by thermal energy.
The standard unit is Kelvin which also compares it to volume at constant pressure of a given gas.
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What is the ph of 0.05l of hand soap? is it acidic or basic?
A sample of cobalt has a mass of 27 g and a density of 9 g/cm^3. What would be its volume?
Moving electrons are found to exhibit properties of.
Answer:
both particles and waves
Explanation:
this is known as wave-particle duality.
I hope this helps.
Have a nice day.
Which would you expect to have the
highest pH (closest to 14)?
Answer:
yes
Explanation:
im pretty sure yes, also i think this is 20 characters long
Match the following items.
1. not affected by a magnet
2. mostly space
3. flows freely but particles still attract
4. positively charged particles
5. free to move in all space
6. negatively charged particles
7. atoms nearly fixed in space
8. helium nucleus
proton
solid
liquid
gamma ray
gas
atoms
electron (beta)
alpha particles
Answer:
1. not affected by a magnet 1 liquid
2. mostly space 2 solid
3. flows freely but particles still attract 3 proton
4. positively charged particles 4 gas
5. free to move in all space 5 alpha particles
6. negatively charged particles 6 atoms
7. atoms nearly fixed in space 7 gamma ray 8. helium nucleus 8 electron (beta)
4- If 10 ml of a 1.5 M H2SO4 solution has been diluted by adding 100 ml of water to the original solution, what is the final concentration of the solution?
The final concentration of a solution that has been diluted by adding 100 ml of water to the original solution is 0.15M.
How to calculate concentration?
The concentration of a solution can be calculated using the following formula:
C1V1 = C2V2
Where;
C1 = initial concentration
C2 = final concentration
V1 = initial volume
V2 = final volume
1.5 × 10 = 100 × C2
15 = 100C2
C2 = 0.15M
Therefore, the final concentration of a solution that has been diluted by adding 100 ml of water to the original solution is 0.15M.
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1kg of hydrogen is burned in oxygen how much energy is released
Answer:
121 million joules energy is released
Explain :
As there are 500 moles of hydrogen gas in a kilogram, this means that burning a kilogram of hydrogen gas releases 500 times as much energy or 121 million joules .