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Likurg_2 [28]
2 years ago
14

The differential cross section for scattering 6.5-MeV alpha particles at 120° off a silver nucleus is about 0.5 barns/sr. If a t

otal of 10 10 alphas impinge on a silver foil of thickness 1 itm and if we detect the scattered particles using a counter of area 0.1 mm 2 at 120° and 1 cm from the target, about how many scattered alphas should we expect to count? (Silver has a specific gravity of 10.5, and atomic mass of 108.) 14.12 ***
Chemistry
1 answer:
Burka [1]2 years ago
8 0

Answer:

Nsc=30

Explanation:

The solid angle subtended by the counter is

d=0.1mm2/(1cm)2=(10)3 sr

d=(10)10x10.5gcm3x10-4cm/108x1.6610x10-24gx0.510-24cm2x10-3=30

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Consider the following reactions and their respective equilibrium constants: NO(g)+12Br2(g)⇌NOBr(g)Kp=5.3 2NO(g)⇌N2(g)+O2(g)Kp=2
maxonik [38]

Answer:

Equilibrium constant of the given reaction is 1.3\times 10^{-29}

Explanation:

NO+\frac{1}{2}Br_{2}\rightleftharpoons NOBr....(K_{p})_{1}=5.3

2NO\rightleftharpoons N_{2}+O_{2}....(K_{p})_{2}=2.1\times 10^{30}

The given reaction can be written as summation of the following reaction-

2NO+Br_{2}\rightleftharpoons 2NOBr

N_{2}+O_{2}\rightleftharpoons 2NO

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

N_{2}+O_{2}+Br_{2}\rightleftharpoons 2NOBr

Equilibrium constant of this reaction is given as-

\frac{[NOBr]^{2}}{[N_{2}][O_{2}][Br_{2}]}

=(\frac{[NOBr]}{[NO][Br_{2}]^{\frac{1}{2}}})^{2}(\frac{[NO]^{2}}{[N_{2}][O_{2}]})

=\frac{(K_{p})_{1}^{2}}{(K_{p})_{2}}

=\frac{(5.3)^{2}}{2.1\times 10^{30}}=1.3\times 10^{-29}

7 0
2 years ago
Read 2 more answers
In the citric acid cycle, after the acetyl-group (2C) from acetyl-CoA is transferred to oxaloacetate (4C) to produce citrate (6C
Alborosie

Answer:

The carbons of the acetyl group oxidize which generate CO2, and in turn H2O.

Explanation:

The pyruvic acid that is generated during glycolysis enters the mitochondria. Inside this organelle, the acid molecules undergo a process called oxidative decaborxylation in which an enzyme of several cofactors is involved, one of which is coenzyme A. Pyruvic acid is transformed into an acetyl molecule and these are been introduced to the begining of the Krebs Cycle where the acetyl-group (2C) from acetyl-CoA is transferred to oxaloacetate (4C) to produce citrate (6C). As the molecule cycles the two carbons of the acetyl oxidize and are released in the form of CO2. Then the energy of the Krebs cycle becomes sufficient to reduce three NAD +, which means that three NADH molecules are formed. Although a small portion of energy is used to generate ATP, most of it is used to reduce not only the NAD + but also the FAD which, if oxidized, passes to its reduced state, FADH2

8 0
2 years ago
Calculate the number of grams of solute in 500.0 mL of 0.189 M KOH.
KIM [24]

Answer : The number of grams of solute in 500.0 mL of 0.189 M KOH is, 5.292 grams

Solution : Given,

Volume of solution = 500 ml

Molarity of KOH solution = 0.189 M

Molar mass of KOH = 56 g/mole

Formula used :

Molarity=\frac{\text{Mass of KOH}\times 1000}{\text{Molar mass of KOH}\times \text{Volume of solution in ml}}

Now put all the given values in this formula, we get the mass of solute KOH.

0.189M=\frac{\text{Mass of KOH}\times 1000}{(56g/mole)\times (500ml)}

\text{Mass of KOH}=5.292g

Therefore, the number of grams of solute in 500.0 mL of 0.189 M KOH is, 5.292 grams

7 0
2 years ago
Read 2 more answers
Zinc metal is added to hydrochloric acid to generate hydrogen gas and is collected over a liquid whose vapor pressure is the sam
mafiozo [28]

Question:

Zinc metal is added to hydrochloric acid to generate hydrogen gas and is collected over a liquid whose vapor pressure is the same as pure water at 20.0 degrees C (18 torr). The volume of the mixture is 1.7 L and its total pressure is 0.987 atm. Determine the number of moles of hydrogen gas present in the sample.

A. 0.272 mol

B. 0.04 mol

C. 0.997 mol

D. 0.139 mol

E. 0.0681 mol

Answer:

The correct option is;

E. 0.0681 mol

Explanation:

The equation for the reaction is

Zn + HCl = H₂ + ZnCl₂

Vapor pressure of the liquid = 18 torr = 2399.803 Pa

Total pressure of gas mixture H₂ + liquid vapor = 0.987 atm  

= 100007.775 Pa

Therefore, by Avogadro's law, pressure of the hydrogen gas is given by the following equation

Pressure of H₂ = 100007.775 Pa - 2399.803 Pa = 97607.972 Pa

Volume of H₂ = 1.7 L = 0.0017 m³

Temperature = 20 °C = 293.15 K

Therefore,

n = \frac{PV}{RT} =  \frac{100007.775 \times 0.0017 }{8.3145 \times 293.15} = 0.068078 \ moles

Therefore, the number of moles of hydrogen gas present in the sample is n ≈ 0.0681 moles.

7 0
2 years ago
Which of the following mixtures, with each component present at a concentration of 0.1 M, has a pH closest to 7? O A. HCIO(aq) a
eduard

for HClO, pKa = 7.54

for HNO_2, pKa = 3.15                                    

for CH3 COOH, pKa = 4.74    

Explanation:

The concentration of the solution given is 0.1 M has a pH closest to 7

The mixtures are weak acids and their salts except

HNO_3 and NaNO_3                                         pH = pH is near to '1'

for buffers( acidic)                                               pH = pKa + log [salt] / [acid]

therefore [salt] = [acid] = 0.1                               pH = pKa + log 0.1 / 0.1 = pKa

                                                     pH = pKa

for HClO, pKa = 7.54

for HNO_2, pKa = 3.15                                     therefore HClO and NaclO

                                                                         mixture hs a pH closest to '7'

for CH3 COOH, pKa = 4.74                

5 0
2 years ago
Read 2 more answers
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