radium-223 decays with a half-life of 11.4 days, how long will it take for a 0.240-mol sample of radiuim to decay to 1.88 x 10-3 mol

The sample of white powder contains 47.1% K2CO3 and 0.39% Na2CO3.

Molar mass of sodium carbonate = 106 g/mol

Molar mass of potassium carbonate = 138 g/mol

Number of moles of HNO3 = 10/1000 L × 0.8903 M = 0.008903 moles

Mass of HNO3 =  0.008903 moles × 63 g/mol = 0.56 g

Mass of sample added = 1.091 g

Mass of sample left over = 0.573 g

Mass of sample reacted = 1.091 g - 0.573 g = 0.518 g

The reacted sample contains xg of Na2CO3 and (0.518 - x) g K2CO3.

Na2CO3 + 2HNO3 --> 2NaNO3 + CO2 + H2O

106g of Na2CO3 reacts with 126g of HNO3

x g of Na2CO3 reacts with (126 × x/106)g of HNO3

K2CO3 + 2HNO3 --> 2KNO3 + CO2 + H2O

138 g of K2CO3 reacts with 126 g of HNO3

(0.518 - x) g of K2CO3 reacts with [(0.518 - x) × 126/138] g

Total mass of HNO3 used;

1.19x + 0.47 + 0.91x = 0.56

2.1x + 0.47 = 0.56

2.1x = 0.56 - 0.47

2.1x = 0.09

x =  0.09/2.1

x = 0.0043 g

Mass of K2CO3 = (0.518 - x) g = 0.518 - 0.0043 = 0.5137 g

Mass percent of K2CO3  = 0.5137 g/ 1.091 g × 100/1 = 47.1%

Mass percent of Na2CO3 = 0.0043/1.091 g × 100/1 = 0.39%

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Balanced:

2NaOH + CO2 → Na₂CO₃ + H₂O

Explanation:

To balance an equation, the amount of atoms on each side must be equal.

Atom Count on Reactant Side:

Atom Count On Product Side:

As you see, to simply balance the equation, put the 2 in order for the atom count on the reactant side to be equal to the product side. The 2 will add one more of each atom so that its the same as the product side.

When the value of secondary quantum number (l) = 1, the magnetic quantum number can be from -1 to +1. The answer would be false.

The angular quantum number (l) can take any integer between 0 and the value of the principal quantum number (n) less by 1.

In other words, l can be from 0 to n-1.

The magnetic quantum number (m), on the other hand, can take any value between -l to +l.

For example, if l = 1, m can be -1,0, and +1.

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Explanation:

since 5g saturates 12.5g of water at 10°c

so......x would saturate 50g of water at 0°c

then you can cross multiply

In this case, according to the given information about the oxidation numbers and the compounds given, it turns out possible to figure out the oxidation number of manganese in both MnI2, manganese (II) iodide and MnO2, manganese (IV) oxide, by using the concept of charge balance.

Thus, we can define the oxidation state of iodine and oxygen as -1 and -2, respectively, since the former needs one electron to complete the octet and the latter, two of them.

Next, we can write the following [tex]x[/tex], since manganese has five oxidation states, and it is necessary to calculate the appropriate ones:

[tex]Mn^xI_2^-\\\\Mn ^xO_2^{-2}[/tex]

Next, we multiply each anion's oxidation number by the subscript, to obtain the following:

[tex]Mn^xI_2^-\rightarrow x-2=0;x=+2\\\\Mn ^xO_2^{-2}\rightarrow x-4=0;x=+4[/tex]

Thus, the correct choice is Manganese has an oxidation number of +2 in Mnl2 and +4 in MnO2.

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Answer:

Answer D. Picture II shows a chemical change, because the same substance changes form

Explanation:

This is the temperature that water molecules slow down enough to stick to each other and form a solid crystal

Answer:

D Im 90% Sure

Explanation:

If its not right i owe you one I did this one before

Answer:

H3PO4 + 3KOH--------->  K3PO4 + 3H2O

Explanation

H3PO4 + KOH------------> K3PO4 + H20

when an hydrogen ion containing acid (HX) reacts with a hydroxide containing base(BOH)  they produce water and a "salt".

water can be called  dihydrogen oxide (H2O), but it can also be called

hydrogen hydroxide (HOH)...same thing.

so the phosphoric acid (H3PO4) contains 3 hydrogen ions (H), and needs 3

hydroxide ions to from 3 hydrogen hydroxides .. that is 3 waters AND A "SALT" WITH THE REMAINING SPECIES ( K AND PO4)      

so let us balance

H3PO4 + 3KOH--------->K3PO4 + 3HOH  or

H3PO4 + 3KOH--------->  K3PO4 + 3H2O

Check:

6 H on the left side, 6 H on the right side

1 P on the left side, 1 P on the right side

3 K on the left side, 3 K on the right side

7 O on the left side, 7 O on the right side

abadabaabdabadaba........that's all folks

yup it is balanced

Answer:

Cell are the smallest life units on this planet

Explanation:

Answer:

c. 2-dimethyl-2-butene or 3-dimethyl-1-butene

Answer:

landslide mudflows slump and creep

Explanation:

no explanation

two layers of different liquids=two phases.

Because oil doesn't dissolve in water. It only floats on water.

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The reducing agent in the reaction 2Li(s) + Fe(CH₃COO)₂(aq) → 2LiCH₃COO(aq) + Fe(s) is lithium (Li).

The general reaction is:

2Li(s) + Fe(CH₃COO)₂(aq) → 2LiCH₃COO(aq) + Fe(s)   (1)

We can write the above reaction in two reactions, one for oxidation and the other for reduction:

Li⁰(s) → Li⁺(aq) + e⁻   (2)

Fe²⁺(aq) + 2e⁻ → Fe⁰(s)    (3)

We can see that Li⁰ is oxidizing to Li⁺ (by losing one electron) in the lithium acetate (reaction 2) and that Fe²⁺ in iron(II) acetate is reducing to Fe⁰ (by gaining two electrons) (reaction 3).  

We must remember that the reducing agent is the one that will be oxidized by reducing another element and that the oxidizing agent is the one that will be reduced by oxidizing another species.

In reaction (1), the reducing agent is Li (it is oxidizing to Li⁺), and the oxidizing agent is Fe(CH₃COO)₂ (it is reducing to Fe⁰).  

Therefore, the reducing agent in reaction (1) is lithium (Li).  

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I hope it helps you!

This  problem provides the molar mass and radius of a metal that has an BCC unit cell and the density is required.

Firstly, we consider the formula that relates molar mass and also includes the Avogadro's number and the volume of the unit cell:

[tex]\rho =\frac{Z*M}{V*N_A}[/tex]

Whereas Z stands for the number of atoms in the unit cell, M the molar mass, V the volume and NA the Avogadro's number. Next, since BCC is able to hold 2 atoms and M and NA are given, we calculate the volume of the atom in the unit cell given the radius in meters:

[tex]V=a^3=(\frac{4R}{\sqrt{3} } )^3=(\frac{4*1.74x10^{-10}m}{\sqrt{3} } )^3=6.49x10^{-29}m^3[/tex]

And finally the required density in g/cm³:

[tex]\rho =\frac{2*341.1g/mol}{6.49x10^{-29}m^3\frac{m^3}{atom} *6.022x10^{23}\frac{atom}{mol} } =17455257.8g/m^3\\\\\rho=17.5g/cm^3[/tex]

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Answer:

The formula for Avagadro's law is V1/n1 = V2/n2, where V = volume and n = amount of gas (in moles).

Explanation:

Answer:

D NO3 Nitrate is a nitrogen oxoanion formed by loss of a proton from nitric acid.

Answer:

A. because there both high pitched voice and low pitched ( girls have sweet, shrill ,high pitched good voice ) where as boys have horase ,low pitched medium voice )

Answer:

NaHCO3

Explanation:

The three is small at the bottom at the end

Explanation:

Sorry, I don't know, but I can tell you that when an atom, or a body, has the same amount of positive charges (protons) and negative charges (electrons), it is said to be electrically neutral. ... The net charge corresponds to the algebraic sum of all the charges that a body possesses.

Answer: Neutral carbon-12 (or any carbon atom) has 6 electrons with a total negative charge of 6e- orbiting a nucleus with a total positive charge of 6e+, so that the total net charge is zero. The nucleus is made up of 6 protons, each with a positive charge of e+, and 6 neutrons, each with zero charge.

Explanation:

Answer:

atom

Explanation:

The sodium atom has a single valence electron that it can easily lose. (If the sodium atom loses its valence electron, it achieves the stable electron configuration of neon.) The chlorine atom has seven valence electrons and can easily gain one electron.

The major product obtained when 1-hexyne is treated with H2 and Pd is; 1-hexene.

The structure of 1-hexyne is such that it possesses a triple bond around its first Carbon in it's carbon chain.

On this note; hydrogenation by treatment with H2 and Paladium, Pd as catalyst yields 1-hexene as the major product.

PS: Paladium, Pd is the major constituent of the Lindlar's catalyst.

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Yes according to reliable sources.

Answer:

this the partial removal of a substance from a solution or mixture by dissolving it in another immiscible solvent in which it is more soluble.

Answer: Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. These processes are called chemical reactions and, in general, are not reversible except by further chemical reactions.

A physical change is are changes affecting the form of a chemical substance, but not its chemical composition. Physical changes are used to separate mixtures into their component compounds, but can not usually be used to separate compounds into chemical elements or simpler compounds.

Answer:

Explanation:

I hope this helps

Answer:

Explanation:

The material that is not a mixture; it has the same properties all the way through is called a substance. Thus the material that is not a mixture; it has the same properties all the way through is called a substance.

ALL THE BEST :)

Answer:

44

Explanation:

Answer:

a reaction in which electrons are transferred between different atoms

Explanation:

I took the test and got it right :)

c. a reaction in which electrons are released from the system

Oxidation:

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Answer:one mole of gold

Answer:

Neon 10,  mass: 20.18

Explanation: