Answer:
6.9399amu
Explanation:
Isotopes are elements with same atomic number but different atomic masses.
To determine the average atomic mass one must multiply the absolute atomic mass (amu) of each isotope times its absolute atomic mass. This will give the weight average contribution of each isotope. The sum of the weight average contributions gives the final weight average atomic mass of the element. The wt. avg. atomic mass is the value posted on the periodic table.
It is recommended that a table be sketched in the following form ...
Isotope | % fractional amt. X Isotopic mass(amu) => Wt. Avg**.
Li-6 7.59% => 0.0759 x 6.015amu => 0.4565
Li-7 92.41% => 0.9241 x 7.016amu => 6.4835
*amu => atomic mass units ∑ Li-6 + Li-7 = 6.9399amu
**Wt.Avg. => weight average contribution of isotope = fractional amt x Isotopic mass(amu)
*** Final Wt. Avg. = ∑Wt.Avg. Contributions (value posted of periodic table)
What is the molarity of a solution that contains 45 mEq Ca“ per liter?
Answer:
0.0225 M
Explanation:
In one liter of this solution, there are 45 mEq of Ca⁺².
1 mEq of Ca⁺² is equal to 20 mg of Ca⁺. We know this by dividing its molar mass (40) by the charge of the ion (2).
Meaning that 45 mEq of Ca⁺² is equal to (45 * 20) 900 mg of Ca⁺².
Now we convert 900 mg of Ca⁺² into moles, using its molar mass:
900 mg / 1000 = 0.9 g0.9 g Ca⁺² ÷ 40 g/mol = 0.0225 mol Ca⁺²Finally we calculate the molarity of the solution:
Molarity = moles / liters0.0225 mol / 1 L = 0.0225 Mif the pressure of 200 cm cube of a gas is half at constant temperature.what will be the new volume
Answer:
hbjeofjwwkjjhhwhhyuhcuh
Explanation:
bjsdhoooiiifckuvghvvr
Lüderitz and Florianopolis are the same distance from the equator and they are both near the ocean. Use the information on the map to answer these questions: How does the air temperature of Lüderitz compare to the air temperature of Florianopolis? Why?
Answer: At Luderitz, only a little energy is transferred from the ocean to the air. At Florianopolis, a lot of energy is transferred from the air to the ocean. ... Even though the ocean water at each location is a different temperature, the same amount of energy is transferred to the air at both locations.
Explanation:
Both locations are at the same distance from the equator at Lüderitz, only a little energy is transferred from the ocean to the air. Hence option A is correct.
Where is Lüderitz ocated ?The Lüderitz is a coastal town and is located in southwestern nambia and is known for its colonial buildings. It has a desert climate and moderate temperatures throughout the year.
The windy and cold climate occurs due to the south Atlantic current. The place has a little energy that is transferred from the oceans to the air as compared to Florianopolis hat has lots of energy even though the water has different temperatures same energy is transferred to both locations.
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One essential step in the manufacture of many plant fertilizers is the production of nitrogen monoxide gas, NO(g). This step is represented by the following balanced equation: 4 NH3(g) + 5 O2(g) --> 4 NO(g) + 6 H2O(l)
Determine the amount of oxygen needed to produce 1.2 x 104 mol of nitrogen monoxide gas.
Answer: 1.5 moles, or 48 grams
Explanation:
Set up the following:
[tex]\frac{1.2 x 10^4 mol NO}{1}[/tex] × [tex]\frac{5 mol O2}{4 mol NO}[/tex] = 1.5 moles of O2 needed
If you're also looking for the number of grams needed:
[tex]\frac{1.5 mol}{1}[/tex] × [tex]\frac{32 g}{1 mol}[/tex] = 48 grams needed
Each element is made of
A.many types of atoms
B.the periodic table
C.one type of atom
D.molecules
Not sure if my answers are even correct. i am so confused
Answer:
#3 is the percentage for sodium i believe and 4 is right
Explanation:
PLS ANSWER I WILL MARK U BRAINLIEST AND GIVE U THANK U
A student learns that salts like potassium chloride and sodium chloride are introduced in a weekly conducting solution. What option explains the chemical reactions that salts undergo and affect the conductivity of the solution?
a.Salts react chemically with the water particles and decrease the conductivity of the solution
b. Salts help to make the solution non-conducting by reacting with the particles of the solution
c. Salts mix with the particles of the weak conducting solution and helps to produce oxygen from the solution
d. Salts undergoes a chemical reaction with the particles of the solution and increase its conductivity
Answer:
d. Salts undergoes a chemical reaction with the particles of the solution and increase its conductivity
Explanation:
Salt compounds like potassium chloride (KCl) and sodium chloride (NaCl) mentioned in this question have the ability to disintegrate into their respective ions or charged atoms when dissolved in water. For example;
NaCl (aq) → Na+ + Cl-
However, these ions (Na+ and Cl-) are responsible for the ELECTRICAL CONDUCTIVITY of a solution. Hence, a salt compound when placed in an aqueous solution will form ions, which will conduct electricity. Hence, salinity of a solution increases its conductivity.
According to this question, salts undergoes a chemical reaction to with the particles of the solution to form ions that increase its conductivity.
4 points
1. What is the main source of energy for this food chain? *
Sun
Plants
Fish
Turtles
Sharks
O fish
O turtle
sun
O shark
Answer:
sun
Explanation:
all of the other things get their energy from the Sun
Answer:
sun
Explanation:
the sun is the main source of energy for plants, which are at the bottom of the food chain.
A hot piece of copper was dropped into 155 g of water at 23.6 °C and 2,100 J of energy was transferred to the water. What is the final temperature of the water?
Answer:
26.8 °C
Explanation:
Step 1: Given and required data
Mass of water (m): 155 gEnergy transferred to the water (Q): 2100 JInitial temperature of the water (T₂): 23.6 °CFinal temperature of the water (T₁): ? Specific heat of water (c): 4.184 J/g.°CStep 2: Calculate the final temperature of the water
We will use the following expression.
Q = c × m × (T₂ - T₁)
T₂ = 2100 J/(4.184 J/g.°C) × 155 g + 23.6 °C = 26.8 °C
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Pretty easy question if you know science. 20 Points
A piece of nickel at 25 °C is dropped into a glass of water at 25 °C. Which statement is correct?
Heat will flow from the nickel to the water in the glass.
Heat will flow from the water in the glass to the nickel.
There will be no transfer of heat from the nickel to the water in the glass.
The final temperature of water and nickel will be 0 °C.
Answer:
C.
Explanation:
because the heat From the nickel and the heat from the water are the same.
As a piece of nickel at 25 °C is dropped into a glass of water at 25 °C, there will be no transfer of heat from the nickel to the water in the glass.
To answer the question, we need to know what heat transfer is.
What is heat transfer?This is the flow of heat energy from one body to another over a temperature gradient.
Heat transfer between Nickel at 25 °C and water at 25 °C.
Since a piece of nickel at 25 °C is dropped into a glass of water at 25 °C, there is no temperature gradient, since, both bodies are at the same temperature. Thus, no heat is transferred from the nickel to the water.
So, as a piece of nickel at 25 °C is dropped into a glass of water at 25 °C, there will be no transfer of heat from the nickel to the water in the glass.
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In terms of activation energy, why does increasing the temperature of a
reaction make it proceed more quickly?
A. Increasing the temperature reduces the activation energy.
B. Increasing the temperature increases the potential energy of the
reactants.
O C. Increasing the temperature increases how many reactant
molecules reach activation energy.
D. Increasing the temperature makes the molecules move slower.
Increasing the temperature increases the potential energy of the reactants, thus making the reaction faster.
What is activation energy?Activation energy is the minimum energy that reactant molecules must possess in order to collide together to form products.
Increasing the temperature of a reaction helped to make the reaction proceed faster. This is because more reactant particles acquire the energy greater than or equal to the activation energy.
Therefore, increasing the temperature of a reaction makes it proceed more quickly.
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D: ____________________________________________
E: ____________________________________________
Answer:
I think the awnser would be c urf mom
Explanation:
Write a balanced chemical equation, complete ionic equation and a net ionic equation for Copper lll sulfate and zinc.
Answer: CuSO4 (aq)+ Zn (s) → Cu (s) + ZnSO4(aq)
Explanation: do you mean copper II sulphate CuSO4?
2. Which of the following are reactants of photosynthesis? *
a. carbon dioxide, water and light energy
b. glucose and oxygen
c. carbon dioxide, water and ATP
d. carbon dioxide, glucose and light energy
Answer:
A is the answer.
Select the statements that are true regarding open tubular and packed columns in gas chromatography.
A. For similar analysis times, open tubular columns provide better resolution than packed columns.
B. Packed columns offer increased sensitivity to small sample sizes.
C. Packed columns have a greater sample capacity than open tubular columns.
D. Open tubular columns give better resolution but longer analysis separation times compared to packed columns.
E. Packed columns give broader peaks with longer retention times.
Answer:
true or false :-
a) yes
b) no
c)yes
d)yes
e)no
For similar analysis times, open tubular columns provide better resolution than packed columns, Packed columns have a greater sample capacity than open tubular columns and Open tubular columns give better resolution but longer analysis separation times compared to packed columns are true regarding open tubular. Hence, options A, C and D are correct.
What is gas chromatography used for?The chemical constituents of a sample mixture are identified, separated, and quantified using an analytical technique called gas chromatography.
Gas chromatography is a technique for separating compounds in mixtures by injecting a gaseous or liquid sample into a mobile phase, which is usually referred to as the carrier gas, and passing the gas through a stationary phase. The mobile phase is often composed of an inert gas or an unreactive gas, such as helium, argon, nitrogen, or hydrogen.
Thus, options A, C and D are correct.
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Meredith mixes together 5 grams of baking soda and 5 grams of vinegar in a test tube that is not sealed. She then weighs the product and
finds that it weighs 9 grams. Mathew conducts the same experiment, except in a sealed bag. He finds that 5 grams of baking soda and 5
grams of vinegar will result in 10 grams of product. Which of the following might account for their different findings?
O A. Some of the mass was created during the reaction between vinegar and baking soda in the bag.
OB. Some of the mass of the reactants was converted to light.
O C. Some of the mass escaped from the test tube as a gas before it was massed.
OD. Some of the mass from the test tube was destroyed.
Answer:
simple chemistry experiment—adding baking soda to vinegar—seems to challenge the law of conservation of mass.
Some of the mass escaped from the test tube as a gas before it was massed. Hence option C is correct.
What is experiment?Experiment is defined as a process used to confirm or deny a hypothesis, as well as assess the likelihood or effectiveness of a previously untested idea. Additionally, experiments are used by researchers to confirm or refute new or current theories. The structure or mathematical form of a theory can be hinted at by an experiment, and it can also provide proof that the entities involved in our theories actually exist.
Something new is created when vinegar and baking soda are combined. Carbon dioxide gas soon foams up in the mixture. All of the baking soda can be made to react and dissolve into the vinegar solution if enough vinegar is utilized.
Thus, some of the mass escaped from the test tube as a gas before it was massed. Hence option C is correct.
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High Melting points
Ionic or covalent
ionic
hope this help you
have a good day
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how many grams of oxygen gas are there in a 2.3 L tank at 7.5 atm and 24 C
Answer:
22.6 g
Explanation:
First we use the PV=nRT equation:
P = 7.5 atmV = 2.3 Ln = ?R = 0.082 atm·L·mol⁻¹·K⁻¹T = 24 °C ⇒ 24 + 273.16 = 297.16 KWe input the data:
7.5 atm * 2.3 L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 297.16 KAnd solve for n:
n = 0.708 molThen we convert 0.708 moles of oxygen gas (O₂) to grams, using its molar mass:
0.708 mol * 32 g/mol = 22.6 gmolecular formula citric acid2.A 10.0 mL sample of pineapple juice was titrated with 0.100 M sodium hydroxide solution. The average volume of NaOH required to reach the endpoint was 12.8 mL. a.Calculate the number of moles of sodium hydroxide required to reach the endpoint. Show your work in equation editor. Remember to use units and report your answer to the proper number of significant figures.
Answer: The number of moles of sodium hydroxide required to reach the endpoint is 0.00128
Explanation:
To calculate the number of moles for given molarity, we use the equation:
[tex]\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution in ml}}[/tex]
Molarity of [tex]NaOH[/tex] solution = 0.100 M
Volume of [tex]NaOH[/tex] solution = 12.8 mL
Putting values in equation, we get:
[tex]0.100M=\frac{\text{Moles of}NaOH\times 1000}{12.8ml}\\\\\text{Moles of }NaOH=\frac{0.100mol/L\times 12.8}{1000}=0.00128mol[/tex]
Thus the number of moles of sodium hydroxide required to reach the endpoint is 0.00128
One of the greatest dangers in a tornado is from flying objects. A 15 pound piece of lumber can turn into a flying missile that could severely damage walls and homes. A piece of steel with a mass of 200 pounds and travelling at the same velocity would cause even more damage. Select any evidence from the list below that you could use to explain why a 200 pound piece of steel would cause more damage than a 15 pound piece of wood travelling at the same velocity.
As the kinetic energy of an object increases, the force it can exert on another object decreases.
As the kinetic energy of an object increases, the force it can exert on another object increases.
Objects with more mass have less kinetic energy.
Objects with more mass have more kinetic energy.
As the velocity of an object increases, its kinetic energy decreases.
As the velocity of an object increases, its kinetic energy increases.
Answer:
As the kinetic energy of an object increases, the force it can exert on another object decreases.
Explanation:
Which is an advantage of selling plant fertilizer as a powder rather than as a liquid?
Choose one.
A. The powder must be stored in a childproof container.
B.Transportation costs are reduced.
C.The powder may be a health hazard if proper procedures are not followed during mixing.
D.The gardener has to be able to read directions carefully and mix the proper amount of solvent and solute.
Answer:A
Explanation: because i saw the sheet
Most ecosystems originally get their energy from
For parts a & b below, derive only the initial value problem set up.
A tank of capacity 200 gallons holds 100 gallons of water with 25 pounds of sugar in solution. Pure water is poured into it at the rate of 2 gallons per minute, and the well-stirred mixture flows out of this tank at a rate of gallon per minute and into the second tank that initially contained 50 gallons of fresh water. The well-stirred mixture in the second tank is allowed to leave the tank at the same rate (1 gal/min).
1. Determine an Initial value problem that satisfied by the amount of sugar in the first tank (Tank A).
2. Determine an Initial value problem that satisfied by the amount of sugar in the second tank (Tank B).
Answer:
Explanation:
From the given information:
Let y(t) be the amount of sugar in tank A at any time.
Then, the rate of change of sugar in the tank is given by:
[tex]\dfrac{dy}{dt}= (rate \ in ) - ( rate \ out )[/tex]
The rate of the sugar coming into the tank is 0
[tex]\text{rate of sugar going out }= \dfrac{y(t) \ pound}{100}\times \dfrac{1 }{min} \\ \\ = \dfrac{y}{100} \ pound/min[/tex]
[tex]So; \\ \\ \\ \dfrac{dy}{dt} = 0 - \dfrac{y}{100} \\ \\ \implies \dfrac{dy}{y }= -\dfrac{dt}{100 } \\ \\ \implies dx|y| = -\dfrac{t}{100}+C \\ \\ \implies e*{In|y|}= e^{-\dfrac{t}{100}+C} \\ \\ \implies y = Ce^{-\dfrac{t}{100}}[/tex]
Initial amount of sugar = 25 Pounds
Now; y(0) = 25
25 = Ce⁰
C = 25
So; y(t) = 25 [tex]e^{-\dfrac{t}{100}[/tex]
Thus, the amount of sugar at any time t = [tex]\mathbf{25 e^{^{-\dfrac{t}{100}}}}[/tex]
B) For tank B :
[tex]\dfrac{dy}{dt}= 1 - \dfrac{y}{50 } \\ \\ \dfrac{dy}{dt}= \dfrac{50-y}{50} \\ \\ \dfrac{dy}{50-y }= \dfrac{dt}{50}[/tex]
For the reaction
C2H4(g) + 302(g) → 2002 (g) + 2H20 (8)
if 6.0 mol of CO2 are produced, how many moles of Oz were reacted?
4.0 mol
0 7.5 mol
9.0 mol
o none of these
O 15 mol
Answer:
9.0 mol
Explanation:
C₂H₄(g) + 3O₂(g) → 2CO₂ (g) + 2H₂O (g)In order to convert from moles of CO₂ to moles of O₂, we need to use the stoichiometric coefficients in the balanced reaction. We use a conversion factor that has moles of CO₂ in the denominator and moles of O₂ in the numerator:
6.0 mol CO₂ * [tex]\frac{3molO_2}{2molCO_2}[/tex] = 9.0 mol O₂Organelles carry out specif functions within the cell. True False
Answer:
true
Explanation:
The diagram below represents H2 and Cl2 molecules that will potentially react to form HCI.
Hydrogen
Chlorine
Which of the following best describes this reaction?
А
The limiting reactant is chlorine.
B
The percent yield will be greater than 100%.
с
Hydrogen and chlorine are nonreactive.
D
All molecules shown will react to form the product.
The limiting reactant is chlorine in the given reaction of hydrogen and chlorine. Therefore, the correct option is option A.
What is chemical reaction?A chemical reaction is a procedure that causes one group of chemical components to change chemically into another. Chemical atom bonds are formed and broken during chemical reactions, which traditionally only involve changes in the locations of electrons.
The study of chemical processes involving unstable and radioactive materials, where both electronic or nuclear changes may take place, is known as nuclear chemistry. The limiting reactant is chlorine in the given reaction of hydrogen and chlorine.
Therefore, the correct option is option A.
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What is the molar mass of (NH4)2 CO3
HELP NEED THIS BADLLLLY !!!!!!!!!
Answer:
2 is correct
Explanation:
My friend for you this answer
i need help can someone help. pls
Is grilling a ham and cheese sandwich and chemical or physical change?
Answer:
Physical
Explanation:
I say physical because if you just think about the cheese it wasnt melted before u put that heat on it .