A neutral Atom of silicon-30 contains 14 protons . How many electrons does it have ?

The mass of a proton is 1.00728 amu andthat of a neutron is 1.00867 amu. What is the binding energy pernucleon (in J) of a Co nu

andreyandreev [35.5K]

Answer:

The binding energy per nucleon = 1.368*10^-12 (option D)

Explanation:

<u>Step 1:</u> Data given

The mass of a proton is 1.00728 amu

The mass of a neutron is 1.00867 amu

The mass of a cobalt-60 nucleus is59.9338 amu

Step 2: Calculate binding energy

The mass defect = the difference between the mass of a nucleus and the total mass of its constituent particles.

Cobalt60 has 27 protons and 33 neutrons.

The mass of 27 protons = 27*1.00728 u = 27.19656 u

The mass of 33 neutrons = 33*1.00867 u = 33.28611 u

Total mass of protons + neutrons = 27.19656 u + 33.28611 u = 60.48267 u

Mass of a cobalt60 nucleus = 59.9338 amu

Mass defect = Δm = 0.54887 u

ΔE =c²*Δm

ΔE = (3.00 *10^8 m/s)² *(0.54887 amu))*(1.00 g/ 6.02 *10^23 amu)*(1kg/1000g)

Step 3: Calculate binding energy per nucleon

ΔE = 8.21 * 10^-11 J

8.21* 10^-11 J / 59.9338 = 1.368 *10^-12

The binding energy per nucleon = 1.368*10^-12 (option D)

3 0

3 years ago

A twenty-eight-liter volume of gas contains 11 g methane, 1.5-gram nitrogen and 16-gram carbon dioxide. Determine partial pressu

GREYUIT [131]

Based on Dalton's Law, for a mixture of gases, the total pressure is the sum of the partial pressure of each gas.

Partial pressure (p) of each gas is related to the total pressure (P) as follows:

p = X * P----------(1)

where X is the mole fraction of that gas

X = moles of a particular gas/total number of moles of all gases in the mixture--------------(2)

Step 1: Calculate the moles of each gas

Mass of methane, CH4 = 11 g

Mass of nitrogen, N2 = 1.4 g

Mass of carbon dioxide, CO2 = 16 g

# moles of CH4 = 11 g/16 gmol-1 = 0.6875

# moles of N2 = 1.4/28 = 0.05

# moles of CO2 = 16/44 = 0.3636

Total moles = 0.6875+0.05+0.3636 = 1.1011

Step2: Calculate mole fractions of each gas

Based on equation (2)

X(CH4) = 0.6875/1.1011 = 0.6244

X(N2) = 0.05/1.1011 = 0.0454

X(CO2) = 0.3636/1.1011 = 0.3302

Step 3: Calculate the total pressure

Based on ideal gas equation:

PV = nRT

given that;

V = 28 L

n = total moles = 1.1011

R = gas constant = 0.0821 Latm/mol-K

Since temp T is not given, let us consider room temperature of 25 C = 25 + 273 = 298 K

Now, P = nRT/V = 1.011*0.0821*298/28 = 0.962 atm

Step 3: Calculate partial pressures

Based on equation:

p(CH4) = 0.6244*0.962 atm = 0.601 atm

P(N2) = 0.0454*0.962 atm = 0.044 atm

P(CO2) = 0.3302*0.962 atm = 0.318 atm

4 0

3 years ago

A chemist prepares a solution of magnesium chloride MgCl2 by measuring out 49.mg of MgCl2 into a 100.mL volumetric flask and fil

Flura [38]

Answer: Molarity of $Cl^-$ anions in the chemist's solution is 0.0104 M

Explanation:

Molarity : It is defined as the number of moles of solute present per liter of the solution.

Formula used :

$Molarity=\frac{n\times 1000}{V_s}$

where,

n= moles of solute

$Moles=\frac{\text{Given mass}}{\text{Molar mass}}=\frac{0.049g}{95g/mol}=5.2\times 10^{-4}moles$

$V_s$ = volume of solution in ml = 100 ml

Now put all the given values in the formula of molarity, we get

$Molarity=\frac{5.2\times 10^{-4}moles\times 1000}{100ml}=5.2\times 10^{-3}mole/L$

Therefore, the molarity of solution will be $5.2\times 10^{-3}mole/L$

$MgCl_2\rightarrow Mg^{2+}+2Cl^-$

As 1 mole of $MgCl_2$ gives 2 moles of $Cl^-$

Thus $5.2\times 10^{-3}$ moles of $MgCl_2$ gives = $\frac{2}{1}\times 5.2\times 10^{-3}=0.0104$

Thus the molarity of $Cl^-$ anions in the chemist's solution is 0.0104 M

6 0

3 years ago

Plz i wanna those answers click on the photo to see all the question they are 2 queastions part A and B

dezoksy [38]

Answer:

a.

Turn paper Blue - these are alkaline/ base substances.

Toothpaste
Soap
Bleach

Turn paper Red - these substances are acidic in nature.

Lemon Juice
Vinegar
Cola drink

b. i. A wasp sting - Lemon juice

ii. A bee sting - Toothpaste

iii. A wasp sting is alkaline which means that running an acidic substance like lemon or lemon juice on it should neutralize it.

A bee sting is acidic so an alkaline substance such as toothpaste should neutralize it as well.

6 0

2 years ago

Which of the following is a physical change?

vodka [1.7K]

Hello,
A physical change describes a change that does physically and does not display “chemical” signs which are signs that indicate a precipitate being formed, change in color, density, or producing gas, etc. “Tearing a piece of paper in half” is a physical change because like I said earlier it doesn’t show any chemical change signs. I hope this helps you out!

6 0

3 years ago

Read 2 more answers