Que. 1. Gallium has 2 naturally occuring Isotopes with mass numbers 69 & 71 respectively. What is the percentage abundance of both Isotopes if their relative atomic mass is equal to 70.59 Amu (Atomic mass Unit)
Answers
Isotopes are atoms of the same element that have different masses. The relative atomic mass (am) is a weighted average that takes into account the abundance of each isotope. We can calculate the relative atomic mass using the following expression.
[tex]am = \frac{\Sigma m_i \times ab_i}{100}[/tex]
where,
mi: mass of each isotopeabi: percent abundance of each isotopeFor Gallium,
[tex]70.59 amu = \frac{69 amu\ x + 71 amu\ y}{100}[/tex] [1]
where "x" and "y" are the unknown abundances.
We also know that the sum of both abundances must be 100%.
x + y = 100
y = 100 - x [2]
If we replace [2] in [1], we get
[tex]70.59 amu = \frac{69 amu\ x + 71 amu\ (100-x)}{100} \\7059 amu = -2 amu\ x + 7100amu \\x = 20.5[/tex]
Then, in [2]
y = 100 - x = 100 - 20.5 = 79.5
In conclusion, Ga-69 has an abundance of 20.5% and Ga-71 has an abundance of 79.5%.
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Related Questions
How is thermal energy distributed in most heating systems?
A.
convection
B.
conduction
C.
radiation
Answers
Answer:
By Convection
Explanation:
Which statement includes all the steps in the change that is associated with the enthalpy of solution? solute separation and mixing reaction of reactants to form products. solute and solvent mixing and then separating solute separation, solvent separation, and then mixing
Answers
Answer: solute separation, solvent separation, and then mixing
Explanation:
The enthalpy change of solution simply means the amount of heat which can be released or absorbed when dissolving. The enthalpy of solution is usually expressed at constant temperature in kJ/mol.
The enthalpy of solution requires three main stages:
1. Solute separation: This is when the solute is broken down. In this case, all the intramolecular forces which holds the solute together is broken.
2. Solvent separation: This is when the solvent is broken down all the intramolecular forces which holds the solvent together is broken.
3. Mixing- In this case, the solute and the solvent is mixed for a solution.
If 3.5 kJ of energy are added to a 28.2 g sample of iron at 20 degrees C, what is the final temperature of the iron in kelvins?
Answers
295.8k
that is the procedure above
What must scientists look for in their experiment or their data to make sure it is accurate?
Answers
Answer:
Scientists must look in their experiment/data to check for accuracy because they don't want to make any mistakes, and most importantly have to make sure they have the right information to proceed.
Explanation:
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even if u know how to do one, it's okk
anything helps
Answers
Explanation:
a) HNO2(aq) = HNO3(aq) + H2O(l) +NO(g)
b) SoCl2 (l) + H2O (l) = So2(g) + 2HCl(aq)
c) CH4 (g) + 2O2(g) = Co2 (g) + 2H2O(g)
d) 3CuO(s) + 2NH3 (g) = 3Cu(s) + 3H2O (l) + N2(g)
Plants in forests take up carbon dioxide from the atmosphere during photosynthesis. They transform the carbon dioxide into plant material. When plants die, their organic matter is often worked into the soil by decomposers. Some of this organic matter remains within the soil and forest floor, and some of it is taken up by other living things.
Based on this information, what role do forests play in the carbon cycle?
A.
Forests are carbon sinks because they store carbon.
B.
Forests are carbon sinks because they do not absorb carbon dioxide when plants die.
C.
Forests are carbon sources because they emit carbon.
D.
Forests are carbon sources because they can be burned to emit carbon dioxide.
Answers
Because Trees store carbon and make it oxygen
Answer: B. forests are carbon sinks because they store carbon
Explanation:forests take up carbon from the atmosphere through photosynthesis and from organic matter through decomposition. so, forests are carbon sinks because they store carbon
what is the charge on ion X Li2X
Answers
In the compound Li2X, there are two lithium ions and one X^2- ion.
Ionic compounds are composed of an ion pair of opposite charge. Usually, the positive ion is a metal cation while the negative ion is a non metal anion. The two ions are held together by strong electrostatic interaction.
In the compound Li2X, there are two lithium ions and one X^2- ions. X^2 -is the non metal anion present.
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PLEASE HELP!!!
Write the sentences in your copybook and draw a line through one of the words in
bold to complete each of these sentences about alkali metals correctly.
Alkali metals generally become more / less dense going down the group.
The melting and boiling points of alkali metals increase / decrease down the group.
The softness of alkali metals increases / decreases going down the group.
The speed with which alkali metals react with oxygen increases / decreases going
down the group.
Answers
Answer:
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How many atoms of hydrogen are there in 36 g of NH4?
Answers
Answer:
hope it helps you
Explanation:
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A gas that was heated to 150 Celsius has a new volume of 1587.4 L. What was its volume when its temperature was 100 Celsius?
Answers
Answer:
[tex]\boxed {\boxed {\sf 1058.3 \ L}}[/tex]
Explanation:
We are asked to find the new volume of a gas after a change in temperature. We will use Charles's Law, which states the volume of a gas is directly proportional to the temperature. The formula for this law is:
[tex]\frac {V_1}{T_1}= \frac{V_2}{T_2}[/tex]
The gas was heated to 150 degrees Celsius and had a volume of 1587.4 liters.
[tex]\frac {1587.4 \ L }{150 \textdegree C} = \frac {V_2}{T_2}[/tex]
The temperature was 100 degrees Celsius, but the volume is unknown.
[tex]\frac {1587.4 \ L }{150 \textdegree C} = \frac {V_2}{100 \textdegree C}[/tex]
We are solving for the volume at 100 degrees Celsius, so we must isolate the variable V₂. It is being divided by 100°C and the inverse of division is multiplication. Multiply both sides of the equation by 100°C.
[tex]100 \textdegree C *\frac {1587.4 \ L }{150 \textdegree C} = \frac {V_2}{100 \textdegree C} * 100 \textdegree C[/tex]
[tex]100 \textdegree C *\frac {1587.4 \ L }{150 \textdegree C} = V_2[/tex]
The units of degrees Celsius cancel.
[tex]100 *\frac {1587.4 \ L }{150 } = V_2[/tex]
[tex]100 *10.58266667 \ L = V_2[/tex]
[tex]1058.266667 \ L = V_2[/tex]
The original measurement of volume has 5 significant figures, so our answer must have the same. For the number we calculated, that is the tenth place. The 6 in the hundredth place to the right tells us to round to 2 up to a 3.
[tex]1058.3 \ L = V_2[/tex]
The volume of the gas at 100 degrees Celsius is approximately 1058.3 liters.
Plz Help I have One more time To retake and I can't fail it..
Answers
Answer:
D
Explanation:
A synthesis reaction is a reaction in which two or more reactants combine to form a given product.
If we look closely at option D, you will notice that sulphur and oxygen combined together to form sulphur dioxide. That is a typical example of chemical synthesis.
Hence;
S + O2 ----->SO2 is a synthesis reaction.
The Clean Air Act legislation of 1970, 1977, and 1990 was designed to improve air quality in the United States by monitoring and reducing the emissions of air pollutants judged to pose threats to human health, such as carbon monoxide, nitrogen dioxide, sulfur dioxide, ozone, particulate matter, and lead. The main source of lead emissions in 1970 was the exhaust of vehicles burning gasoline to which tetra-ethyl lead had been added to improve combustion. By 1985, leaded gasoline was phased out of use, although airplanes and racecars were exempted. The 1990 amendments addressed the growing problem of urban smog by
Answers
Answer:
The 1990 amendments addressed the growing problem of urban smog by acid rain.
Explanation:
As shown in the above question, the Clean Air Act was created with the goal of making the US air healthier, while also aiming to reduce the impacts of pollution on the American population. This law had as its main objective to reduce the emission of gases capable of polluting the atmosphere, especially those resulting from the burning of gasoline in cars. In 1990, a new amendment was added to this law. This amendment aimed to reduce emissions of sulfur dioxide and nitrogen oxides, as they were the main cause of acid pollution, which was responsible for acid rain that is extremely dangerous and negative for society.
The volume of a gas at 6.0 atm is 2.5 L. What is the volume of the gas at 75 atm at
the same temperature? (5 points)
1) 1.0 L
0 2 2) 1.5 L
3) 2.0 L
O 4) 3.0L
Answers
The volume of a gas at 6.0 atm is 2.5 L. What is the volume of the gas at 7.5 atm at
the same temperature? (5 points)
1) 1.0 L
2) 1.5 L
3) 2.0 L
4) 3.0L
Answer:
2.0 L
Option C) 2.0L is the correct answer.
Hence, at the same temperature, as the pressure is increased to the given value, the volume of the gas decreases to 2.0L.
Boyle's law
Boyle's law states that "the volume V of a given quantity of gas is inversely proportional to its pressure P as long as temperature remains constant.
Boyle's law is expressed as;
P₁V₁ = P₂V₂
Given the data in the question;
Initial Volume V₁ = 2.5LInitial pressure P₁ = 6.0atmFinal pressure P₂ = 7.5atmFinal volume V₂ = ?To determine the final volume of the gas, we substitute our given values into the expression above.
P₁V₁ = P₂V₂
V₂ = P₁V₁ / P₂
V₂ = ( 6.0atm × 2.5L ) / 7.5atm
V₂ = 15Latm / 7.5atm
V₂ = 2.0L
Option C) 2.0L is the correct answer.
Hence, at the same temperature, as the pressure is increased to the given value, the volume of the gas decreases to 2.0L.
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What is nascent hydrogen?
Answers
Answer:
[H]
Explanation:
This is nascent hydrogen it's a reactive form of hydrogen...
It reduces elements and compounds.
There is a series of nitrogen oxides with the general formula N?O?. What is the empirical formula of one that contains 30.45% nitrogen?
Question 13 options:
N2O
NO
NO2
N2O3
N2O5
Answers
Answer: The empirical formula of one that contains 30.45% nitrogen is [tex]NO_{2}[/tex].
Explanation:
Given: Mass of nitrogen = 30.45 g
Let us assume that the mass of given oxide is 100 grams.
As the atomic mass of nitrogen is 14.0067 g. So, moles of nitrogen will be calculated as follows.
[tex]Moles = \frac{mass}{molarmass}\\= \frac{30.45 g}{14.0067 g/mol}\\= 2.17 mol[/tex]
Also, mass of oxygen = (100 - 30.45) g = 69.55 g
Atomic mass of oxygen is 15.9994 g/mol. So, moles of oxygen will be as follows.
[tex]Moles = \frac{mass}{molarmass}\\= \frac{69.55 g}{15.9994 g/mol}\\= 4.34 mol[/tex]
The ratio of both the atoms is as follows.
[tex]\frac{4.34}{2.17} = 2[/tex]
This means that gas has 2 moles of oxygen to 1 mole of nitrogen. Hence, the formula of oxide is [tex]NO_{2}[/tex].
Thus, we can conclude that the empirical formula of one that contains 30.45% nitrogen is [tex]NO_{2}[/tex].
2.0 kilograms of lithium hydroxide can “scrub”, or remove, how many liters of carbon dioxide at standard conditions?
Answers
Answer:
0.94 L
Explanation:
The equation of the reaction is;
2LiOH + CO2 -----> Li2CO3 + H2O
Number of moles LiOH = 2.0/23.95 g/mol = 0.084 moles
2 moles of LiOH scrubs 22.4 L of CO2
0.084 moles of LiOH scrubs 0.084 moles × 22.4/2
= 0.94 L
The carbon atom forms a part of all the major molecules found in living things. Which of the following doesnot contain carbon?
Answers
Hydrochloric acid or Hcl
Combustion reactions typically involve all of the following except
a. The consumption of oxygen gas
b. The production of a Hydrocarbon
c. The production of water
d. The release of carbon dioxide
Answers
Answer:
b. The production of a HydrocarbonExplanation:
In Combustion reaction usually occurs when a hydrocarbon reacts with oxygen to produce carbon dioxide and water.
How many grams of H2Oare produced when 5.38g of O2
is reacted?
Answers
Answer:
I think this answer should be 2.33 g H2O
Need help fast!!
What is the pH of a solution with a 1.50 x 10-9 M hydroxide ion concentration? (4
points)
1) 0.176
2) 5.18
3) 8.82
4) 9.20
Answers
Answer:
The answer is "5.18 ".
Explanation:
It's a question of chemistry. Therefore, the following solution is provided:
We will first determine the solution's pOH. The following can possible:
The concentration of Hydroxide ion [tex][OH^{-}] = 1.5\times 10^{-9}\ M[/tex]
[tex]pOH =?\\\\pOH = -\log [OH^{-}]\\\\pOH = -\log 1.5\times 10^{-9}\\\\pOH = 8.82\\\\[/tex]
Furthermore, the pH of the solution shall be established. It was provided as follows:
[tex]pOH = 8.82\\\\pH =?\\\\pH + pOH = 14\\\\pH + 8.82 = 14\\\\[/tex]
When collecting all the like terms:
[tex]pH = 14 -8.82\\\\pH = 5.18[/tex]
Therefore, the solution of pH is 5.18.
Please help me
will give the brainliest!
Answers
Explanation:
a) The presence of sulfate ions in a solution can be confirmed by the reaction of barium chloride in an acidic medium.
The balanced chemical equation of the reaction is shown below:
[tex]BaCl_2(aq)+CuSO_4(aq)->CuCl_2(aq)+BaSO_4(s)[/tex]
Hence, the white precipitate is barium sulfate and its formation with the ionic equation is shown below:
[tex]Ba^2^+(aq)+SO_4^2^-(aq)->BaSO_4(aq)[/tex]
b) The presence of copper (II) ions can be confirmed by the following test:
Add potassium iodide solution to copper (II) solution.
Then a white ppt of cuprous iodide along with the liberation of iodine is observed and the entire solution attains brown color.
The chemical equation of the reaction is shown below:
[tex]2CuSO_4(aq)+4KI(aq)->Cu_2I_2(s)+I_2(s)+2K_2SO_4(aq)\\[/tex]
c)(i)Due to this reaction, the blue color of the solution becomes white.
Reddish-brown copper is deposited at the bottom of the container.
(ii)In this reaction, zinc is oxidized.
d) (i) Copper is produced at the cathode.
(ii)[tex]Cu^2^+(aq)+2e^-->Cu(s)[/tex]
(iii) The reaction that takes place at the cathode is reduction.
Reduction is gaining of electrons.
How does the position of an object relate to the energy stored in a object?
Answers
Answer:
An object can store energy as the result of its position. For example, the heavy ball of a demolition machine is storing energy when it is held at an elevated position. This stored energy of position is referred to as potential energy. Similarly, a drawn bow is able to store energy as the result of its position
Answer:
you can see the attached file is scanned the same level of detail of the heart the heart and I am a little bit of an emergency you can see it on the heart the tree is the best of luck for tomorrow be in a few days and times are available in a while back and forth to be a good idea and latitude longitude of
What has an atomic number of 1
Answers
Answer:
Hydrogen
Explanation:
When it’s summer in the northern hemisphere what Season is it in the Southern Hemisphere
Answers
Answer:
Winter
Explanation:
I dont know but whatev
Answer:
Winter
Explanation:
The seasonal cycle in the polar and temperate zones of one hemisphere is opposite to that of the other. Therefore, When it is summer in the Northern Hemisphere, it is winter in the Southern, and vice versa.
hope it helps :)
I need help with question 5
Answers
Answer:
B a spring being stretched
How many moles of KOH are there in 27.5 mL of 0.250 M KOH?
Question 2 options:
4.31 × 10−3 mol KOH
6.88 × 10−3 mol KOH
7.24 × 10−3 mol KOH
8.13 × 10−3 mol KOH
9.21 × 10−3 mol KOH
Answers
Answer:
6.88 × 10^-3mol
Explanation:
Molarity = number of moles (n) ÷ volume (V)
According to this question, there in 27.5 mL of 0.250 M KOH, the number of moles of KOH can, therefore, be calculated as follows:
number of moles = molarity × volume
Volume of KOH = 27.5mL = 27.5/1000
= 0.0275L
n = 0.0275 × 0.250
n = 0.006875 mol
n = 6.88 × 10^-3mol
b) The size of a star is a balance between
2 things. Explain this statement.
Answers
Answer:
Luminosity is the amount of light that a star radiates. The size of the star and its surface temperature determine its luminosity. Apparent magnitude of a star is its perceived brightness, factoring in size and distance, while absolute magnitude is its true brightness irrespective of its distance from earth
Explanation:
Calcular la m y M de una concentración Porcentual 45% m/m, la cual tiene una D solución 1.25 g/ml y una masa de sto de 125g.HN03
Answers
Explanation:
Calculate the "m" and "M" of a percentage concentration of 45% m / m, which has a solution D 1.25 g / ml and a mass of 125g.
Given data is:
The mass % of the solution is 45%.
The density of the solution is 1.25 g/mL.
The mass of the solution is 125 g.
Molarity of solution is:
[tex]M=\frac{number of moles of solute}{volume of solution}[/tex]
The volume of the solution is:
[tex]Volume=\frac{mass}{density} \\=125 g / 1.25 g/ml\\=100 mL[/tex]
From mass% of the solution, the mass of solute HNO_3 can be calculated.
[tex]mass percent=\frac{mass of solute}{ mass of solution} \\45=(mass of HNO_3/125 g)x100\\\\mass of solute = 56.25g[/tex]
The number of moles of HNO3 is :
[tex]n_H_N_O__3=\frac{m_H_N_O__3}{M_H_N_O__3}[/tex]
[tex]=56.25 g/63.00g/mol\\\\=0.893mol[/tex]
The molarity is:
[tex]M=n/V\\M=0.893 mol/0.1L\\M=8.93 M[/tex]
The molality is:
[tex]m=n/mass of solvent in kg\\ =0.893 mol /(0.125-0.05625)kg\\ = 12.9 m[/tex]
Number of sodium atom(s) in salt (NaCl)
Answers
Answer:
NaCl consists of one atom each of sodium and chlorine. Hence, each molecule of NaCl has 2 atoms total.
Explanation:
Answer: There is only one atom of sodium in NACL
Explanation: But in total there two atoms because 1 sodium and 1 chlorine added all together
HOPE THIS HELPS!!!!
A nut cracker is second lever. Give reason.
Answers
Answer:
the load is between the fulcrum and the handle
Explanation:
