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3 years ago

The

Chemistry

1 answer:

Marat540 [252]3 years ago

4 0

Answer:

Isotopes

Explanation:

Isotopes are atoms of the same element that contain an identical number of protons, but a different number of neutrons. Despite having different numbers of neutrons, isotopes of the same element have very similar physical properties.

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What did Ernest Rutherford s gold foil experiment demonstrate about atoms?

Ghella [55]

-Positively charged nucleus
-Empty spaced
-Dense core

5 0

4 years ago

Calculate the energy required to heat 406.0mg of cyclohexane from 33.5°C to 38.9°C . Assume the specific heat capacity of cycloh

N76 [4]

Answer:

Q = 4.056 J

Explanation:

Q = m<em>C</em>ΔT

∴ m = 406.0 mg = 0.406 g

∴ <em>C </em>= 1.85 J/g.K

∴ T1 = 33.5°C ≅ 306.5 K

∴ T2 = 38.9°C = 311.9 K

⇒ ΔT = 311.9 - 306.5 = 5.4 K

⇒ Q = (0.406 g)(1.85 J/gK)(5.4 K)

⇒ Q = 4.056 J

6 0

3 years ago

1. The solubility of lead(II) chloride at some high temperature is 3.1 x 10-2 M. Find the Ksp of PbCl2 at this temperature.

solniwko [45]

Answer:

1) The solubility product of the lead(II) chloride is $1.2\times 10^{-4}$ .

2) The solubility of the aluminium hydroxide is $1.6\times 10^{-10} M$ .

3)The given statement is false.

Explanation:

Solubility of lead chloride = $S=3.1\times 10^-2M$

$PbCl_2(aq)\rightleftharpoons Pb^{2+}(aq)+2Cl^-(aq)$

S 2S

The solubility product of the lead(II) chloride = $K_{sp}$

$K_{sp}=[Pb^{2+}][Cl^-]^2$

$K_{sp}=S\times (2S)^2=4S^3=4\times (3.1\times 10^{-2})^3=1.2\times 10^{-4}$

The solubility product of the lead(II) chloride is $1.2\times 10^{-4}$ .

Concentration of aluminium nitrate = 0.000010 M

Concentration of aluminum ion = $1\timed 0.000010 M=0.000010 M$

Solubility of aluminium hydroxide in aluminum nitrate solution = $S$

$Al(OH)_3(aq)\rightleftharpoons Al^{3+}(aq)+3OH^-(aq)$

S 3S

The solubility product of the aluminium nitrate = $K_{sp}=1.0\times 10^{-33}$

$K_{sp}=[Al^{3+}][OH^-]^3$

$1.0\times 10^{-33}=(0.000010+S)\times (3S)^3$

$S=1.6\times 10^{-10} M$

The solubility of the aluminium hydroxide is $1.6\times 10^{-10} M$ .

$Molarity=\frac{Moles}{Volume (L)}$

Mass of NaCl= 3.5 mg = 0.0035 g

1 mg = 0.001 g

Moles of NaCl = $\frac{0.0035 g}{58.5 g/mol}=6.0\times 10^{-5} mol$

Volume of the solution = 0.250 L

$[NaCl]=\frac{6.0\times 10^{-5} mol}{0.250 L}=0.00024 M$

1 mole of NaCl gives 1 mole of sodium ion and 1 mole of chloride ions.

$[Cl^-]=[NaCl]=0.00024 M$

Moles of lead (II) nitrate = n

Volume of the solution = 0.250 L

Molarity lead(II) nitrate = 0.12 M

$n=0.12 M]\times 0.250 L=0.030 mol$

1 mole of lead nitrate gives 1 mole of lead (II) ion and 2 moles of nitrate ions.

$[Pb^{2+}]=[Pb(NO_2)_3]=0.030 M$

$PbCl_2(aq)\rightleftharpoons Pb^{2+}(aq)+2Cl^-(aq)$

Solubility of lead(II) chloride = $K_{sp}=1.2\times 10^{-4}$

Ionic product of the lead chloride in solution :

$Q_i=[Pb^{2+}][Cl^-]^2=0.030 M\times (0.00024 M)^2=1.7\times 10^{-9}$

$Q_i$ ( no precipitation)

The given statement is false.

3 0

4 years ago

How would you prepare 3.5 L of a 0.9M solution of KCl?

PolarNik [594]

$V=3,5L\\
Cm=0,9M\\
M_{KCl}=74\frac{g}{mol}\\\\
C_{m}=\frac{n}{V}\\\\
n=\frac{m}{M}\\\\
C_{m}=\frac{m}{MV} \ \ \ \Rightarrow \ \ \ m=C_{m}MV\\\\
m=0,9\grac{mol}{L}*74\frac{g}{mol}*3,5L=233,1g$

B. Add 233 g of KCl to a 3.5 L container; then add enough water to dissolve the KCl and fill the container to the 3.5 L mark.

4 0

3 years ago

Cobalt-60 is produced by neutron activation. in this process, one neutron is absorbed by the nucleus of the parent isotope. what

kkurt [141]

The parent isotope is cobalt-59 (see the picture below).

The mass number is 59 and atomic number is 27 of the parent isotope.

Neutron activation is the process in which atomic nucleus capture free neutron or neutrons.

Cobalt-60 is produced in nuclear reactors in process of neutron activation from parent isotope cobalt-59 (see the picture below).

Atomic number (Z) is total number of protons and mass number (A) is total number of protons and neutrons in a nucleus.

Cobalt-59 and cobalt-60 are the isotopes of chemical element cobalt.

Isotopes are chemical elements with same atomic number (Z), but different mass number (different number of neutrons).

More about isotopes: brainly.com/question/364529

#SPJ4

6 0

2 years ago