As the name implies, a secondary standard is used by standard laboratories, which include companies involved in the preparation of reagents and kits, as well as laboratories responsible to produce quality control material for use by other laboratories. They use the primary standard as the primary calibrator or primary reference material, and they calibrate their instruments against it. Smaller labs use secondary standards to calibrate control material for analysis of unknown concentrations. For smaller labs, secondary standard serves as an external quality control. As a result, it is essential that the secondary standard be standardized against the primary standard before it can be applied.
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how many moles of methane are produced when 4.53 mol co2 reacts
Answer:
2.25 moles
Explanation:
thats correct answer
Thank you
.
Rocks containing _____ have magnetic properties.
lodestar
iron
magnesia
magnetite
Answer: Iron
Explanation: There are little minnerals that make it magnetic.
NH4NO3+Zn(OH)2
Balance the equation
Answer:
Balanced equation: Zn (NO 3) 2 + 2 NH 4 OH = 2 NH 4 NO 3 + Zn (OH) 2 Reaction type: double replacement
Explanation:
The ground electron configuration of a Tc atom is (Kr) 5s2 4d5. What is the electron configuration of a Tc3 ion
Answer:
2:1 of Tc in the periodic table
Chem dissociation!
Calculate degree of dissociation of electrolyte, if you know that in the 2 M solution there is 0.2 mol of this electrolyte as ions.
Answer:
C. Strong electrolytes can be expected to 100% dissociate in aqueous solution
Explanation:
explain chemical equilibrium
Answer:
chemical equilibrium, condition in the course of a reversible chemical reaction in which no net change in the amounts of reactants and products occurs. A reversible chemical reaction is one in which the products, as soon as they formed, react to produce the original reactants.
Explanation:
chemical equilibrium is the state in which both reactants and products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the system.
Kinetic friction is the frictional force needed to start an object at rest into
motion.
O A. True
O B. False
Answer:false you are welcome
Explanation:
Answer: False I hope this helpful please mark me brainlist
Explanation:
Kinetic friction is the friction acting upon a moving object. It would be the frictional force against you if you pulled a box across a table.Static friction is the frictional force needed to overcome to get an object at rest into motion.
The more solute is broken down in solution the less conductive the solutions is. True or False
Answer:
False.
Explanation:
If the answer to this question was true, then that would mean that the more the solute is broken down, the less it'll dissolve... and everyone know that this doesn't make sense. I hope I explained this is an easy manner so you could understand! Good luck! :)
The more solute is broken down in solution the more conductive the solutions is and the statement is False.
What effects the conductive nature of a solution?
Conductivity depends upon solvation of ions present in solution. Greater the solvation of ions, lesser is the conductivity.
Solvation is the process in which molecules of a solvent attract the particles of a solute.
The main forces in solvation are ion-dipole and hydrogen bonding attractions.
The more concentrated a solution is, the greater the conductivity measured (if the solute is a conductor in solution). This is because the higher the concentration of the solute, the more ions will be available to carry electric charge.
Therefore, the more solute is broken down in solution the more conductive the solutions is and the statement is False.
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What is the total number of atoms contained in 3.63 moles of nickel?
Answer:
Explanation:
1 mole of nickel contains 6.02 * 10^23 atoms
3.63 mols of nickel contain x atoms.
What you have is a proportion. A proportion consists of 2 ratios or 4 parts.
Of the 4 parts, you know three of them. The problem is to solve for the 4th.
1/3.63 = 6.02*10^23 / x Cross multiply
x = 3.63 * 6.02* 10^23 Combine the right.
Answer: x = 2.19*10^24 atoms
6. Two flasks at the same temperature are joined by a glass tube with a stopcock. Flask A is a 4.0 L flask containing
N2(e) at 2.0 atm, while flask B is a 10.0 L flask containing CO(g) at 1.4 atm. What is the final pressure in the flasks
after the stopcock is opened?
Hints:
Determine the final volume for the gases leasy!).
.
The final pressure in the flasks (containing N₂ and CO) after the stopcock is opened is 1.57 atm
How to determine the mole in flask AVolume (V) = 4 L Pressure (P) = 2 atm Temperature (T) = STP = 273 KGas constant (R) = 0.0821 atm.L/Kmol Number of mole (n) =?n = PV / RT
n = (2 × 4) / (0.0821 × 273)
n = 0.357 mole
How to determine the mole in flask BVolume (V) = 10 L Pressure (P) = 1.4 atm Temperature (T) = STP = 273 KGas constant (R) = 0.0821 atm.L/Kmol Number of mole (n) =?n = PV / RT
n = (1.4 × 10) / (0.0821 × 273)
n = 0.625 mole
How to determine the final pressure Total volume (V) = 4 + 10 = 14 L Total mole (n) = 0.357 + 0.625 = 0.982 moleTemperature (T) = STP = 273 KGas constant (R) = 0.0821 atm.L/Kmol Pressure (P) =?P = nRT / V
P = (0.982 × 0.0821 × 273) / 14
P = 1.57 atm
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Explain how humans get muscle cramps
Answer:
Humans get muscle cramps when they start sport movemement wih out training and there is a store of calorie and amino acids so when it heated fastly there were some disease like muscle cramps
The force of a hammer drives a nail into wood. This is an example of? A. An unbalanced force. B. Gravitational force. C. Friction. D. Balanced forces.
Answer:
The answer is A. an unbalanced force
Explanation:
This is because the force from the hammer on the nail causes a force that unbalanced normal forces on the nail.
______ contributes to the nitrogen cycle by removing nitrogen from the air and converting it into a form that is usable by plants.
plants
earthworms
fungi
bacteria
The complete statement is "Bacteria contribute to the nitrogen cycle by removing nitrogen from the air and converting it into a form that is usable by plants." This is further explained below.
What is Bacteria?Generally, Bacteria are mono-celled tiny creatures that can be beneficial. Bacteria are germs with a simpler cell structure than many other creatures.
In conclusion, Bacteria contribute to the nitrogen cycle by removing nitrogen from the air and converting it.
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Answer:bacteria
Explanation:
Suggest some ways in which you might determine whether a particular water solution contains an acid or a base.
The use of the pH scale and litmus paper are the ways which can determine whether the solution is an acid or base.
How pH scale and litmus paper tell about acidic and basic solution?The pH scale is the way which determine the acidic or basic nature of a solution. If the pH of a solution is less than 7, it is considered as acidic. If the pH is 7, the solution is neutral and if the pH is greater than 7,the solution is basic.
While on the other hand, litmus paper also tells us about acidic and basic nature of solution. if the litmus paper turns red, it means the solution is acidic whereas if the litmus paper turns blue it means basic.
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For the reaction shown, find the limiting reactant for each of the initial quantities of reactants 4Cr + 3o2 -> 2Cr2O3 d)14.8 mol Cr; 10.3 mol O2
Answer: O2
Explanation:
The balanced chemical equation is:
4 Cr + 3 O2 ---> 2 Cr2O3
4 mol of Cr reacts with 3 mol of O2 to form 2 mol of Cr2O3
For 14.8 mol of Cr, 11.1 mol of O2 is required
But we have 10.3 mol of O2
So, O2 is the limiting reagent
The ________________and ______________ of magma cause igneous rocks to form.
Answer:
The solidifying/cooling and crystallizing of magma causes igneous rocks to form.
Granite is part of the crust layer of the earth.
True
False
Answer:
That would be True
Explanation:
granite is a part of the crust layer.
14. Calculate the mass in grams of oxygen required to react completly with 0.75 moles of Aluminum.
4Al + 302 → 2Al2O3
a. 32 g of Oxygen
b. 18 g of Oxygen
c. 16 g of Oxygen
d. 9.0 g of Oxygen
Moles of O_2:-
0.75(0.75)0.5625molMass of O_2:-
moles(Molar mass)0.5625(32)18gOption B
As per the given balanced reaction, 0.75 moles of aluminum metal requires 0.56 moles of oxygen gas for completely reaction. One mole of oxygen gas is 32 g. Then, mass of 0.56 moles is 18 g.
What is aluminum oxide ?Metals and metal like elements such as aluminum Al are more reactive towards atmospheric oxygen and forms their oxide layers in the metallic surface.
Al₂O₃ is an essential mineral of aluminum formed by the reaction with oxygen as given in the balanced chemical equation. As per this equation, 4 moles of Al requires 3 moles of oxygen for complete reaction.
The number of moles of oxygen required by 0.75 moles of Al is:
(0.75 × 3) /4 = 0.56 moles.
one mole of oxygen weighs 32 g/mol.
mass of 0.56 moles of O₂ = 32 × 0.56 = 18 g.
Therefore, the mass required by 0.75 moles of Al in the reaction is 18 g.
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A sample of PH3, occupying 1.50 L at 25 oC and 0.80 atm, reacts with 0.080 atm, reacts with 2.28L of O2 at 20.0 oC and 0.100 atm according to the following equation:
4 PH3(g) + 8 O2(g) => P4O10(s) + 6 H2O(g)
How many grams of each product is produced? How many grams of each reactant are left at the end of the reaction? What is the final pressure at the end of the reaction? (The final volume is 3.88L and the final temperature is 22.5C).
The ideal gas equation can be used to obtain the pressure, number of moles, volume and temperature of a gas.
What is the ideal gas equation?The ideal gas equation gives the relationship between pressure, number of moles, volume and temperature.
To obtain the number of moles of PH3
PV = nRT
n = PV/RT
n = 0.80 atm * 1.50 L/0.082 atmL/Kmol * 298 K
n = 0.049 moles
Number of moles of O2
PV = nRT
n = PV/RT
n = 0.100 atm * 2.28L /0.082 atmL/Kmol * 293 K
n = 0.0095 moles
Fom the reaction equation;
4 moles of PH3 reacts with 8 moles of O2
0.049 moles of PH3 reacts with 0.049 moles * 8/4 moles
= 0.098
Hence O2 is the limiting reacatant.
Mass of P4O10 produced =
8 moles of O2 yields 1 mole of P4O10
0.0095 moles of O2 yields 0.0095 moles * 1 mole/8 moles
= 0.0012 moles
Mass of P4O10 = 0.0012 moles * 284 = 0.34 g
Mass of water;
8 moles of O2 yields 6mole of water
0.0095 moles of O2 yields 0.0095 moles * 6 moles/8 moles
=0.0071 moles
Mass of water = 0.0071 moles * 18 g/mol = 0.13 g
Since 4 moles of PH3 reacts with 8 moles of O2
x moles of PH3 reacts with 0.0095 moles of O2
x = 0.0048 moles
Moles of PH3 left over = 0.049 moles - 0.0048 moles = 0.0442 moles
Mass of PH3 left over = 0.0442 moles * 34 g/mol
= 1.5 g
No mass of O2 is left over because the limiting reactant is used up.
Total moles of gas left after the reaction = 0.0442 moles + 0.0071 moles = 0.0513 moles
P = nRT/V
P = 0.0513 moles * 0.082 atmL/Kmol * 295.5/3.88L
P= 0.32 atm'
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What separation technique would most likely be used if a solvent were
saved?
A. Melting point separation
B. Distillation separation
C. Density separation
O D. Chromatography separation
The statement, that describes separation technique would most likely be used if a solvent were saved is "distillation separation."
What is separation technique?Separation techniques are methods for separating two different states of matter, such as liquid and solid. Methods that employ variations in physical qualities to separate the components of a mixture, such as evaporation, distillation, filtration, and chromatography, can be used to physically separate the components of a mixture.
Simple distillation is a technique for removing a solvent from a solution. Water, for example, can be extracted from salt solution by simple distillation. If a solvent was saved, the separation procedure would most likely be used is distillation.
Hence the correct option is B.
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what are chemical reaction
Example:-
Burning of waxWe cannot pull back the reaction to get wax back .
Answer:
Explanation:
The permanent change in which a new substance is formed is called a chemical reaction.
For example:
i)Burning of wood
ii)Cooking rice
iii)Forming curd from milk
The burning of wood is a chemical reaction because it is a permanent change and it cannot be reversed. Once it is done, it is over it can't be done again. And in the case of example iii, the milk turns into curd by chemical reaction. A new substance i.e curd is formed from the milk.
Hope you understood!
A solution consists of 35.00 g of CuSO4 dissolved in 250.0 mL of water. The molar mass of Cu is 63.55 g/mol the molar mass of S is 32.07 g/mol, and the molar mass of O is 16.00 g/mol. What is the molarity of the solution?
The molarity of a solution that contains 35.00 g of CuSO4 dissolved in 250.0 mL of water is 0.88M.
How to calculate molarity?The molarity of a solution can be calculated using the following formula:
Molarity = no of moles/volume
According to this question, a solution consists of 35.00 g of CuSO4 dissolved in 250.0 mL of water.
no.of moles of CuSO4 = 35g ÷ 159.6g/mol
no. of moles of CuSO4 = 0.22 moles
Therefore; molarity of CuSO4 solution is calculated as follows:
M = 0.22 ÷ 0.25
M = 0.88M
Therefore, the molarity of a solution that contains 35.00 g of CuSO4 dissolved in 250.0 mL of water is 0.88M.
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A 260.0 −mL buffer solution initially contains 2.5×10−2 M of HCHO2 and 2.5×10−2 M of NaCHO2
What mass of the correct reagent should you add (in grams)?
Express your answer using two significant figures.
The mass of HCHO2 and NaCHO2 to be added to the buffer solution are 0.23g and 0.44g respectively
Data;
Volume of solution = 260mLconc. of HCHO2 = 2.5*10^-2Mconc. of NaCHO2 = 2.5*10^-2MMass of Reagent AddedTo calculate the mass of reagent added, let's start with HCHO2
The mass of HCHO2 to be added is the number of moles of HCHO2 multiplied by it's molar mass.
[tex]260*10^-^3 * 2.5*10^-^2 * 46 = 0.229 = 0.23g[/tex]
The mass of NaCHO2 to be added in the buffer solution is
[tex]260*10^-^3*2.5*10^-^2*68 = 0.442 = 0.44g[/tex]
The mass of HCHO2 and NaCHO2 to be added to the buffer solution are 0.23g and 0.44g respectively
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How many orbitals are in Phosphorus
1. List the actual volume of titrant needed to produce a color change for Sample A and Sample B. Answer: Volume of titrant needed to produce a color change for Sample A:\ ml Volume of titrant needed to produce a color change for Sample B: ml
Answer: B Hope this helps :)
One material property that is widely used and recognized is the strength of a material. But what does the word "strength" mean? "Strength" can have many meanings, so let us take a closer look at what is meant by the strength of a material. We will look at a very easy experiment that provides lots of information about the strength or the mechanical behavior of a material, called the tensile test.
The basic idea of a tensile test is to place a sample of a material between two fixtures called "grips" which clamp the material. The material has known dimensions, like length and cross-sectional area. We then begin to apply weight to the material gripped at one end while the other end is fixed. We keep increasing the weight (often called the load or force) while at the same time measuring the change in length of the sample.
Explanation:
(Squirrels gather and store acorns for the winter, which is an example of a ___________ adaptation.)
A. Mimicry
B. Behavioral
C. Structural
D. Environmental
Answer:
C
Explanation:
New materials can be constructed molecule-by-molecule and atom-by-atom using ______________ in their design.
An ion has 14 protons and a charge of “+2”. How many electrons does it have?
Answer : 12
It has a +2
Take it out from 14
Which of the following are characteristics of stratovolcanoes? Select all that apply.
More common near convergent boundaries
More common at hotspots
Effusive eruptions
Explosive eruptions
High viscosity magma
Low viscosity magma
Answer:
More common near convergent boundaries
Explosive Eruptions
Low Viscosity Magma
Explanation:
Hot spots like hawaii are better known for shield volcanoes. The magma is high viscosity which causes them to build pressure before erupting, leading to explosive eruptions.
how have your thoughts changed about Evolution overtime
Answer:
monkey see, monkey do
Explanation:
boom :)
Answer:
I think it's a game with me and I will knock out a bit and I hope you are u all the way you can get a little bit of a good time to come over here in a bit of the world