A standard lanthanum solution is prepared by dissolving 0.1968 grams of lanthanum oxide (La2O3) in excess nitric acid and diluting to one liter in a volumetric flask. Calculate the concentration of the solution expressed as molarity of lanthanum nitrate and as ppm lanthanum.

Answers

Answer 1

Answer:

1.208x10⁻³M and 392.5ppm La(NO3)3

Explanation:

The reaction that occurs is:

La2O3 + 6HNO3 → 2La(NO3)3 + 3H2O

Molarity is defined as the moles of solute (In this case, LaO3) per liter of solution. And ppm, are mg of solute per liter of solution.

To solve this question we must find the moles of La(NO3)3 produced and its mass in milligrams to find molarity and ppm:

Moles La2O3 -Molar mass: 325.81g/mol-

0.1968g * (1mol / 325.81g) = 6.04x10⁻⁴ moles La2O3

Moles La(NO3)3:

6.04x10⁻⁴ moles La2O3 * (2mol La(NO3)3 / 1mol La2O3) = 1.208x10⁻³ moles La(NO3)3

Molarity:

1.208x10⁻³ moles La(NO3)3 / 1L =

1.208x10⁻³M

Mass La(NO3)3 -Molar mass: 324.92g/mol-

1.208x10⁻³ moles La(NO3)3 * (324.92g / mol) = 0.392.5g La(NO3)3

In mg:

392.5mg La(NO3)3 / 1L =

392.5ppm La(NO3)3


Related Questions

Q.
.No.of valence electrons present in 4.2g of nitride ion (N^(3- are:
(a) 2.4times N
(b) 4.2times N
(c) 1.6times N
(d) 3.2times N ​

Answers

Answer:

if na is Avogadros number then number of vaclence electron in 4.2 g of nitride ions (N3-is.2.4Na. so the answer is 2.4 na

Explanation:

Mass N3- ion = 14 g/mol. So,

4.2 g X (1 mol/14 g) = 0.3 mol N3-

Number of N3- ions = 0.3 mol X 6.02 X 10^23 ions/mol = 1.8 X 10^23 ions

Each N3- ion has 8 valence electrons, so total number of valence electrons = 1.8 X 10^23 X 8 = 1.4 X 10^24 valence electrons.

hope it helps

Experiment: Select the DATA tab, and check that every species is selected. Click Advance year 10 times. Which fish populations increased, and which fish populations decreased?

Answers

arts Per Thousand ... Click advance year 10 times. ... Which organism was most hurt by increased storms, and why do you think this is so? ... On the Coral Reef tab I see less fish and on the Data tab I see Staghorn Coral has majorly decreased. ... B. How does this change the populations of the two species that eat algae, ...

Answer:

increase: yellow tail snapper

decrease: grouper, parrotfish, angelfish

Explanation:

Which is the right answer

Answers

Answer:

NH3

Explanation:

there is one nitrogen and 3 hydrogen

What causes severe weather to occur?

Answers

Answer:

i hope this helps

...............................

Butene would have __ carbon atoms and a __ bond

Answers

Answer:

Butene would have 4 carbon atoms and a double bond.

Explanation:

The chemical formula for butene is C[tex]_4[/tex]H[tex]_8[/tex]

Here is an image of it.

Answer:

we have

But :4

bond :ene :2

So

Butene would have _4_ carbon atoms and a _2_ bond

A sample of nitrogen gas in a 750.0 mL sealed flask exerts a pressure of 206.58 kPa. Calculate the temperature of the gas if the flask contains 3.00 grams of gas.

Answers

Answer:

T= -99 °C.

Explanation:

Hello there!

In this case, according to the given description of the problem, it is possible for us to analyze this problem via the ideal gas equation:

[tex]PV=nRT[/tex]

However, we first calculate the moles in 3.00 grams of nitrogen gas (28.01 g/mol):

[tex]n=3.00g*\frac{1mol}{28.01g}=0.107mol[/tex]

Next, we solve for the temperature as shown below:

[tex]T=\frac{PV}{Rn}[/tex]

Next, we convert the given pressure and volume to atm and L to obtain:

[tex]T=\frac{(206.58atm/101.325)*750.0L/1000}{0.08206\frac{atm*L}{mol*K}*0.107mol}\\\\T=174.15K-273.15\\\\T=-99\°C[/tex]

Regards!

what are 2 factors that impact the flow of energy into and out of earths systems

Answers

Answer:

Solar energy causes evaporation; uneven heating of the Earth causes air masses to move; Coriolis forces help storms to take shape; and gravity makes rivers flow downhill. Another relevant factor is the high heat capacity (or specific heat) of water.

Explanation:

hoped this helped;)

1. What two things reflect some of the incoming solar radiation back out into space?

Answers

Answer:

About 29 percent of the solar energy that arrives at the top of the atmosphere is reflected back to space by clouds, atmospheric particles, or bright ground surfaces like sea ice and snow

The combustion of fuel oil to heat a home is an example of a/an???????

Answers

Answer:

Is it multiple choice? you didnt have any choices

Explanation:

Answer:

exothermic reaction

Explanation:

If 5.60 mol of a substance releases 14.9 kJ when it decomposes, what is ΔH for the process in terms of kJ/mol of reactant?

Answers

Answer:

The correct approach is "-2.67 kJ/mole". A further solution is described below.

Explanation:

The given values are:

No. of moles,

= 5.60 mol

Substance releases,

ΔH = 14.9 kJ

Now,

The ΔH in terms of kJ/mol will be:

= [tex]\frac{\Delta H}{5.60}[/tex]

On putting the given values of ΔH, we get

= [tex]\frac{-14.9}{5.60}[/tex]

= [tex]-2.67 \ kJ/mole[/tex]

What is the amount of space that a material takes up ?

Answers

volume.

The amount of space a material occupies is its volume.

Mass is measured using a scale. Volume is the amount of space matter takes up. Volume can be measured by multiplying the length, width, and height of an object, or by using a measuring cup and seeing how the measurement of water changes in a cup. Density is the amount of matter an object has in a certain space.

Answer:

Volume

Explanation:

Mass is measured using a scale. Volume is the amount of space matter takes up. Volume can be measured by multiplying the length, width, and height of an object, or by using a measuring cup and seeing how the measurement of water changes in a cup. Density is the amount of matter an object has in a certain space.

which type of bonding involves sharing valence electrons, but the valence electrons aren't confined to a specific region between atoms and instead exist throughout the crystal structure of the material?

Answers

Answer:

metallic bonding

Explanation:

Metallic bonding is bonding where electrons exist as "sea of electrons" meaning they can go anywhere in the structure and are not localized in specific place like covalent bonds are sometimes.

What happens when a current is applied to two electrodes immersed in pure water?

A. No electrolysis occurs, and current does not flow.

B. Oxygen, but not hydrogen, is released as a gas.

C. Electrolysis occurs, releasing oxygen and hydrogen gas.​

Answers

Answer:

b

Explanation:

Gucci ghhvhjhsgjjn hvh

Answer:

B

Explanation:

Calculate the mass percent for a solution of 6.5 g KOH in 250 g water

Answers

Answer:

2.53%

Explanation:

mass percent = (mass of solute/mass of solution)×100%

mass percent = [6.5 g/(6.5 + 250) g]×100% = 2.53%


Mg + 2HCl → MgCl2 + H2
How many grams of Mg is needed to produce 100 g of H2?

Answers

H2

n=m÷Mr

n=100×2

n=200 moles

Mole ratio

Mg : H2

1 : 1

x : 200

cross multiply= x=200

Mg

make m the subject

m=n×Mr

m=200×24.305

m=4861 g

What is the electron configuration of the sodium atom after it loses an electron?

Multiple choice question.

A)
1s22s22p6


B)
[He]2s22p5


C)
1s22s22p63s1


D)
1s22s22p63s1

Answers

Answer:

the answer is A 1s22s22p6

Covalent bonding occurs when... a electrons are shared between atoms b cations attract to anions c protons fuse in the nucleus d electrons are transferred between atoms

Answers

Answer: Covalent bonding occurs when electrons are shared between atoms. The correct option is A.

Explanation:

When atoms form a bond by sharing one or more pairs of electrons the bond is referred to as a COVALENT BOND. This is so because CV there is a natural drive for atoms to attain the electronic configuration of Group 0 which has a completely filled outermost shell of eight electrons. The covalent bond usually occurs among non- metals. Example of covalent bonding is seen in the formation of chlorine and carbondioxide molecules. Chloride atom which contains seven electrons in its outermost shell shares an electron with another chloride atom to attain a filled outermost shell leading to the formation of a chlorine molecule.

The characteristics of a covalent compound includes:

--> they contain only molecules. There are no ions, hence they do not conduct electricity.

--> they dissolve in organic solvents. They are insoluble in water.

--> they have low melting and boiling points.

If we were to add a piece of solid Cu to an aqueous solution (in water) of silver nitrate, the Silver would be replaced in a single replacement reaction forming aqueous copper (II) nitrate and solid silver. How much silver, in grams, is produced if 15.00 grams of Cu is added to the solution of silver nitrate

Answers

Answer:

50.9 g of Ag

Explanation:

Reaction is:

Cu (s) + 2AgNO₃(aq)  →  2Ag (s) + Cu(NO₃)₂ (aq)

1 mol of Cu react to 2 moles of silver nitrate in order to produce 2 moles of solid silver and 1 mol of copper (II) nitrate.

We assume, the silver nitrate in excess.

We determine moles of copper → 15 g . 1mol / 63.55 g = 0.236 moles

Ratio is 1:2. 1 mol of copper produce 2 moles of silver

0.236 moles of Cu will produce (0.236 . 2) / 1 = 0.472 moles of Ag

We deterine mass of silver:

0.472 mol . 107.87 g /mol = 50.9 g

What is the molality of an acetic acid solution that contains 0.500 mol of HC2H3O2 (molar mass: 60g/mol) in 0.800 kg of water?

Answers

Answer: The molality of given acetic acid solution is 0.625 m.

Explanation:

Given: Moles of solute = 0.5 mol

Mass of solvent = 0.8 kg

Molality is the number of moles of solute present in a kg of solvent.

Therefore, molality of the given solution is calculated as follows.

[tex]Molality = \frac{moles}{mass of solvent}[/tex]

Substitute the values into above formula as follows.

[tex]Molality = \frac{moles}{mass of solvent}\\= \frac{0.5 mol}{0.8 kg}\\= 0.625 m[/tex]

Thus, we can conclude that the molality of given acetic acid solution is 0.625 m.

The empirical formula of a compound is HC2CI and the g-molar mass is 182 What is the molecular formula ?

Answers

Answer:

tyr4v

Explanation:

hc2ci  g molar mass 182 =  hc2ci =200

The type(s) of food groups that provide the body with muscle repair and
healing is

Answers

Answer:

Protein

Explanation:

Which builds muscles

These would be your proteins
They build and repair our muscles
These can be found in beans and meats

(b)
Calculate the amount of iron that can be extracted from 2000 tonnes of haernatíte.
(Relative atomic masses: O = 16; Fe = 56)

Answers

Answer:

Explanation:

i have already given the answer earlier. you could click this link:

https://brainly.com/question/23568294

Explain using complete sentences as well as sketch a graph of the relationship between the following variables of a gas when all other variables are held constant:
pressure and volume

pressure and temperature

volume and temperature

Answers

Answer:

Pressure and volume relationship, Boyle's law

The relationship between pressure and volume of a gas is given by Boyle's law which states that at constant temperature, the pressure of a given mass of gas is inversely proportional to its volume

Mathematically, we have;

P ∝ 1/V

Please find attached the graph of the relationship between pressure and volume, created with MS Excel

Pressure and temperature relationship, Gay lussac's Law

The pressure of a given mass of gas is directly proportional with the absolute temperature of the gas, provided the volume remains constant

Mathematically, we have;

P ∝ T

Please find attached the graph of the relationship between pressure and temperature, created with MS Excel

Volume and Temperature relationship, Charles Law

The relationship between the volume of a given mass of gas and its pressure is given by Charles law, which states that the volume of a given mass of gas is directly proportional to its absolute temperature, given that the pressure of the gas is kept constant

Mathematically, we have;

V ∝ T

Please find attached the graph of the relationship between volume and temperature, created with MS Excel

Explanation:

what does the prefix non-represent?

1.) 9 carbon atoms, only
2.) 9 carbon atoms and 20 hydrogen atoms
3.) 9 carbon atoms and 18 hydrogen atoms
4.) 9 carbon atoms and 16 hydrogen atoms

Answers

Answer:

1.) 9 carbon atoms, only

Explanation:

Prefix: non- simply means 9.

Suffix: -ene means double bond, -yne means triple bond, and -ane means single bonded carbons.

Answer:

1st option

Explanation:

it means 9 carbon atoms omly

What must happen to uranium before it can be used as a fuel source?

A. No changes are necessary.

B. Stable U-235 must be enriched with 3% radioactive U-238.

C. Stable U-238 must be enriched with 3% radioactive U-235.

D. Unstable U-235 must be enriched with 5% U-238 to stabilize it.​

Answers

Answer:

D

Explanation:

Before it can be used in a reactor for electricity generation, however, it must undergo a series of processes to produce a useable fuel. For most of the world's reactors, the next step in making the fuel is to convert the uranium oxide into a gas, uranium hexafluoride (UF6), which enables it to be enriched.

Unstable U-235 must be enriched with 5% U-238 to stabilize it.​ Hence, option D is correct.

What is radioactive?

Radioactivity is the phenomenon of the spontaneous disintegration of unstable atomic nuclei into atomic nuclei to form more energetically stable atomic nuclei.

Before uranium can be used in a reactor for electricity generation, however, it must undergo a series of processes to produce a useable fuel.

For most of the world's reactors, the next step in making the fuel is to convert the uranium oxide into a gas, uranium hexafluoride (UF6), which enables it to be enriched.

Hence, option D is correct.

Learn more about radioactive here:

https://brainly.com/question/1770619

#SPJ2

Use the information provided in the table to
determine the K, for methylammonium ion, the
conjugate acid of methylamine.
X6.8 x 10-19
4.4 x 1010
2.8 x 109
2.3 x 10-11

Answers

Answer: D

Explanation:

2.3x10-11

Answer:

D. 2.3 x 10^-11

Explanation:

Look at the image below

Which of the following is NOT a type of mucle tissue?

Cardiac


Smooth


Striped


Skeletal

Answers

Answer:

Striped should be the answer

Skeletal is not a muscle tissue

is NaHCO3 a binary compound​

Answers

Answer:

No

Explanation:

Binary compounds contain only 2 distinct elements.

For example magnesium oxide MgO is a binary compound.

NaHCO3 contains 4 distinct elements.

3.) If you have 784 g of Sulfuric Acid (H2SO4), how many moles of Sulfuric
Acid is that? *

Answers

Answer:

98.07848

Explanation:

I assume you are converting between grams H2SO4 and mole. You can view more details on each measurement unit: molecular weight of H2SO4 or mol This compound is also known as Sulfuric Acid. The SI base unit for amount of substance is the mole.

Answer:

8moles

Explanation:

n=m/GFM

n=784/98.02

n=7.998

n=8moles

A gas with a volume of 250 mL at a temperature of 293K is heated to 324K. What is the new volume of the gas?

Answers

Answer:

you can simply answer vl/t1=v2/t2

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