Uranium, an important component of both nuclear weapons and nuclearreactors, has two major isotopes, U-238, which has a half-life of approximately billion years, and U-235, which has a half-life of approximately million years. Both were present in equal amounts at the time of thecreation of the Earth, billion years ago. How many years after the creationof the Earth had the amount of radiation from uranium decayed to half theamount present at the time of the creation of the Earth

Answer:

pH = 5.85

Explanation:

The reaction of methylamine with HCl is:

CH₃NH₂ + HCl → CH₃NH₃⁺ + Cl⁻

As the titration was made with two solutions with the same molarity, the final concentration of the CH₃NH₃⁺ ion is 0.100M ([CH₃NH₃⁺] = 0.100M)

Then, the conjugate acid will be in equilibrium with water as follows:

CH₃NH₃⁺(aq) + H₂O(l) ⇄ CH₃NH₂(aq) + H₃O⁺(aq)

And the equilibrium constant, Ka, of this reaction is:

Kw/Kb = Ka =  1.0x10⁻¹⁴ / 5.0x10⁻⁴= 2x10⁻¹¹

2x10⁻¹¹ =  [CH₃NH₂] [H₃O⁺] / [CH₃NH₃⁺]

As both CH₃NH₂ and H₃O⁺ comes from the same equilibrium we can say:

[CH₃NH₂] = [H₃O⁺] = X

And as we know [CH₃NH₃⁺] = 0.100M:

2x10⁻¹¹ =  [X] [X] / [0.100M]

2x10⁻¹² = X²

X = 1.414x10⁻⁶M = [H₃O⁺]

And as pH= -log [H₃O⁺]

Answer:

answer is TE

Explanation:

Answer:

Tellurium is more reactive than Oxygen

Answer:

The air molecules that are surrounding the metal will speed up, and the molecules in the metal will slow down.

Explanation:

There will be a transfer of thermal energy (heat) from the hot metal plate to the surrounding air. This transfer of energy equates to a transfer of kinetic energy in the molecules. As the plate loses heat, the molecules in the plate will lose kinetic energy and slow down. As the surrounding air gains heat, the molecules will gain kinetic energy and speed up.

Answer: C

Explanation:

Answer:

Explanation:

The standard molar mass is:

For (S )-1-chloro-4-ethyl-2-methylhexane = 162.5 g/mol

For triphenylphosphine  = 262 g/mol

For  ( S )-1-chloro-4-ethyl-2-methyl triphenylphosphonium = 424.5 g/mol

The mass required for 81% yield = [tex]\dfrac{81}{100} \times Theoretical \ yield = 4.15 g[/tex]

Theoretical yield = [tex]\dfrac{4.15}{0.81}[/tex]

= 5.1235 g

thus, since 424.5 g yield produce from 162.5 g

∴

5.1235 g yield will produce = [tex]\dfrac{162.5}{424.5}\times 5.1235 \ g[/tex]

= 1.9613 g of alkyl halide (-chloro) required.

Also, since 424.5 g yield produce from 262 g phosphine

∴

5.1235 g yield will produce = [tex]\dfrac{262}{424.5}\times 5.1235 \ g[/tex]

= 3.1622 g of triphenylphosphine required.

Explanation:

this is the answer of your question .

hope it helped you

Explanation:

The reaction is

2Fe+3Cl2

→2FeCl3

So the mol ratio

Cl2÷FeCl3=3÷2

So for 14 mols of F

eCl3

we need 32×14=21

mols of Cl2

Answer:

Explanation:

From the information given:

left half-cell = 3.00 mM     M(NO)

right half-cell = 3.00 M       M(NO)

Since the electrode are the same in both cells, then the concentration for the cell are also the same.

Negative electrode = Anode = lower concentration = 3.00 mM

Positive electrode = cathode = higher concentration = 3.00 M

Thus, right half cell will be postive electrode.

To determine the concentration cell:

[tex]Ecell =\Big( \dfrac{2.303\times R\times T}{nF} \Big)log\Big(\dfrac{[cathode]}{[anode]}\Big)[/tex]

SInce [Cathode] > [anode],

[tex]R = 8.314 J/K/mol, \\ \\ T = 273+20 = 293 K \\ \\ Faraday's constant (F)= 96500 C/mol[/tex]

n = 3

[tex]Ecell ={ \dfrac{2.303\times 8.314\times 293 }{(3\times 96500)}} log\dfrac{3}{0.003}[/tex]

[tex]\mathbf{E_{cell} = 0.0582 V } \\ \\ \mathbf{E_{cell} = 0.06 V}[/tex]

Answer: The total pressure is 7 atm

Explanation:

According to Dalton's law, the total pressure is the sum of individual pressures.

[tex]p_{total}=p_A+p_B+p_C...[/tex]

Given : [tex]p_{total}[/tex] =total pressure of gases = ?

[tex]p_{O_2}[/tex] = partial pressure of oxygen = 2 atm

[tex]p_{N_2}[/tex] = partial pressure of nitrogen = 4 atm

[tex]p_{Ar}[/tex] = partial pressure of argon = 1 atm

putting in the values we get:

[tex]p_{total}=2atm+4atm+1atm[/tex]  

[tex]p_{total}=7atm[/tex]

Thus the total pressure is 7 atm

Answer: The pressure in the can is 4.0 atm

Explanation:

According to ideal gas equation:

[tex]PV=nRT[/tex]

P = pressure of gas = ?

V = Volume of gas = 0.410 L

n = number of moles = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{3.0g}{44.1g/mol}=0.068mol[/tex]

R = gas constant =[tex]0.0821Latm/Kmol[/tex]

T =temperature =[tex]20^0C=(20+273)K=293K[/tex]

[tex]P=\frac{nRT}{V}[/tex]

[tex]P=\frac0.068mol\times 0.0820 L atm/K mol\times 293K}{0.410L}=4.0atm[/tex]

Thus the pressure in the can is 4.0 atm

Explanation:

The general equation for an endothermic reaction is: Reactants + Energy → Products.

Hope it helps :)❤

The equation represents an endothermic reaction is reactants + energy

products.

Endothermic reactions are chemical reactions in which the reactants soak up warm strength from the surroundings to form products.

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Answer:

There's no single cause of depression. It can occur for a variety of reasons and it has many different triggers. For some people, an upsetting or stressful life event, such as bereavement, divorce, illness, redundancy and job or money worries, can be the cause. Different causes can often combine to trigger depression. For example, you may feel low after being ill and then experience a traumatic event, such as a bereavement, which brings on depression.

Answer:

[tex]C_3H_8+5O_2\rightarrow 3CO_2+4H_2O[/tex]

Explanation:

Hello there!

In this case, when coming across combustion reactions whereby hydrocarbons as fuels are burnt in the presence of oxygen, the main products are said to be carbon dioxide and water in agreement to the breaking and rearrangement of bonds due to the collisions among molecules. Thus, for the reaction between propane and oxygen we have the following balanced reaction:

[tex]C_3H_8+5O_2\rightarrow 3CO_2+4H_2O[/tex]

Best regards!

Answer:

[tex]\huge\boxed{BUTANE}[/tex]

Explanation:

Since it is alkane, The suffix used will be "-ane".

Prefix for 4 carbons => "but-"

Hence, the name:

BUTANE

[tex]\rule[225]{225}{2}[/tex]

Hope this helped!

Answer:

i always wear shoes without socks

Explanation:

Answer:

Molar mass of N3H4 name is 84.0761 g/mol

Convert between N3H4Na(CH3) weight and moles

The chemical name for the formula N₃H₄  is Trinitrogen Tetrahydride

        C , P ,  N ,  H ,  S ,  I ,  Br ,  Cl ,  O ,  F .

        So Now for N₃  =  Tri Nitogen

        and for H₄   =  Tetra Hydride

 Therefore the chemical name is Trinitogen Tetrahydride.

To know more about Chemical Compound

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Answer:

m=2.0mol/kg

Explanation:

Hello there!

In this case, according to the formula to compute molality, which requires moles of solute (HCl) and kilograms of solvent (water), we first compute the moles of the former with its molar mass as shown below:

[tex]n=\frac{18.2g}{36.46g/mol}= 0.50mol[/tex]

And then the kilograms of water:

[tex]\frac{250.g}{1000g/kg} =0.250kg[/tex]

Finally, the molality turns out to be:

[tex]m=\frac{0.50mol}{0.250kg}\\\\m=2.0mol/kg[/tex]

Best regards!

Answer:

a

Explanation:

dont have to explain

Answer: The molarity of [tex]Na_2S_2O_3[/tex] is 0.108 M

Explanation:

[tex]KIO_3+5KI+3H_2SO_4\rightarrow 3K_2SO_4+3H_2O+3I_2[/tex]

[tex]2Na_2S_2O_3+I_2\rightarrow Na_2S_4O_6+2NaI[/tex]

To calculate the number of moles for given molarity, we use the equation:

[tex]\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}[/tex]    

[tex]\text{Moles of }KIO_3=\frac{0.0131mol/L\times 21.55}{1000}=2.8\times 10^{-4}mol[/tex]

1 mole of [tex]KIO_3[/tex]  produces = 3 moles of   [tex]I_2[/tex]

[tex]2.8\times 10^{-4}[/tex] moles of [tex]KIO_3[/tex] produces = [tex]\frac{3}{1}\times 2.8\times 10^{-4}=8.4\times 10^{-4}[/tex] moles of [tex]I_2[/tex]  

Now 1 mole of [tex]I_2[/tex] uses = 2 moles of [tex]Na_2S_2O_3[/tex]

[tex]8.4\times 10^{-4}[/tex] moles of [tex]I_2[/tex] uses =  [tex]\frac{2}{1}\times 8.4\times 10^{-4}=1.69\times 10^{-3}[/tex]  moles of [tex]Na_2S_2O_3[/tex]

[tex]\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution in L}}=\frac{1.69\times 10^{-3}\times 1000}{15.65}=0.108M[/tex]

The molarity of [tex]Na_2S_2O_3[/tex] is 0.108 M  

Answer:

standard sea- level pressure,by definition,equals 760 mm of Mercury,14.70 pounds per square inch, 1,013.25x10³ dynes per square centimetre, 1,013.25 millibars,one standard atmosphere,or 101.325 kilopascale

l hope it's helpful for u....

Answer:

Pollen

Explanation:

Pollen is a powdery substance consisting of pollen grains which are male microgametophytes of seed plants, which produce male gametes (sperm cells).

Explanation is in the file

tinyurl.com/wpazsebu

Answer:

V=2.33361811192L or 2.3x10

Explanation:

Using Charles law V1/T1=V2/T2 Remember to convert celcius to kelvin by using the standard temperature 273.15K

3L/(78C+273.15)=V/273.15

Answer:

3.25 moles of H2O

Explanation:

We'll begin by writing the balanced equation for the reaction. This is given below:

2HCl + Ca(OH)2 —> CaCl2 +2H2O

Now, we can obtain the number of mole H2O produced from the reaction as follow:

From the balanced equation above,

2 moles of HCl reacted to produce 2 moles of H2O.

Therefore, 3.25 moles of HCl will also react to produce 3.25 moles of H2O.

Therefore, 3.25 moles of H2O were produced from the reaction.

Answer:

Fractional distillation of crude oil in laboratory

Explanation:

In general, we can sort them according to their boiling point.

We should first place a ball of mineral wool soaked with petroleum into a boiling tube and heat it with a Bunsen flame. At the beginning of the experiment, heat the mineral with a gentle flame, and then more strongly later. The fraction with a lower boiling range will distil out first. Since petrol is quite volatile, it should be condensed by cooling with water or an ice-water bath.

Petrol will be collected first, as it has a lower boiling point than kerosene. It will turn into vapour and condense again in the receive tub in the beaker.

Sodium chloride is the chemical name for salt and is composed of sodium and chlorine, so it is a compound.

Answer:

d

Explanation:

answer d makes the equation balance