A radioactive nuclide is used to detect eye tumors. An atom of this radionuclide contains 15 protons, 15 electrons, and 17 neutrons. Which is symbol of this radionuclide?

1) The Universal gravitaional law, stated by Sir. Isaac Newton, states that the force of gravitational attraction between two objects is directly proportional to the product of their masses and inverse to the square of the distance that separates their centers.

2) Mathematically, it was expressed in this form:

F = G × m₁ × m₂ / d².

where G is the proportinality constant, m₁ and m₂ and the masses of the objects, and d is the distance that separates the centers of the two objects.

3) Then, the answer is that the greatest for of gravitaional attraction is:

- that of the two objects for which the product of the masses is the greates (assumin same distance between them), or

- that of the two objects that are closer (assuming the product of the masses is the same).

Answer:

a) Let's balance the chemical equation for the reaction between HCl and HNO3 to form NOCl, Cl2, and H2O:

First, write the unbalanced equation:

HCl + HNO3 → NOCl + Cl2 + H2O

Now, balance it step by step:

1. Balance the atoms other than hydrogen and oxygen:

HCl + HNO3 → NOCl + Cl2 + H2O

1 1 1

2. Balance the oxygen atoms by adding water (H2O):

HCl + HNO3 → NOCl + Cl2 + H2O

1 1 1 +1

3. Balance the hydrogen atoms by adding HCl on the left side:

HCl + HNO3 → NOCl + Cl2 + H2O

1 1 +1 1 +1

4. Balance the chlorine atoms by adding Cl2 on the left side:

HCl + HNO3 → NOCl + Cl2 + H2O

1 1 +1 1 +1

Now, the equation is balanced.

b) Let's balance the chemical equation for the reaction between CO and I2O5 to form CO2 and I2:

First, write the unbalanced equation:

CO + I2O5 → CO2 + I2

Now, balance it step by step:

1. Balance the atoms other than carbon and oxygen:

CO + I2O5 → CO2 + I2

1 1

2. Balance the oxygen atoms by adding CO2 on the left side:

CO + I2O5 → CO2 + I2

1 1 +2

3. Balance the carbon atoms by adding CO on the left side:

CO + I2O5 → CO2 + I2

1 +1 +2

4. Balance the iodine atoms by adding I2 on the left side:

CO + I2O5 → CO2 + I2

1 +1 +2 +5

Now, the equation is balanced.

Answer:

                251.25 mL of O₂

Solution:

The balance chemical equation is as follow,

                             2 C₂H₂  +  5 O₂     →     4 CO₂  +  2 H₂O

As we know if the gas is acting ideally then 1 mole of any gas at standard temperature and pressure it will occupy exactly 22.4 L or  22400 mL of volume.

Keeping this in mind according to equation,

     44800 mL (2 mol) of C₂H₂ required  =  112000 mL (5 mol) of O₂

So,

                    100.50 mL of C₂H₂ will require  =  X mL of O₂

Solving for X,

                      X =  (100.5 mL × 112000 mL) ÷ 44800 mL

                      X  =  251.25 mL of O₂

The balanced reaction would be:

C2H2 + 5/2O2 = 2CO2 + H2O

We are given the amount of acetylene in the reaction. This will be the starting point of our calculation. We use the ideal gas equation to find for the number of moles.

n = PV / RT = 1.00(.1005 L) / (0.08206 atm L/mol K ) 273.15 K
n= 4.4837 x 10^-3 mol C2H2

4.4837 x 10^-3 mol C2H2 (5/2 mol O2/ 1 mol C2H2) = 0.0112 mol O2

V = nRT/P = 0.0112 mol O2 x 273.15 K x 0.08206 atm L/mol K / 1 atm
V=0.25125 L or 251.25 mL

the answer is domains.................