Answer:
Explanation:
To start with, the mass of a substance is centered on the amount of particles contained in it.
Mass of a substance measure is the same anywhere it is taken.
In chemistry, the concept of mole is used to find the exact estimate of the number of entities in a sample.
A mole of substance is quantity that is used to express the number of particles contained in it.
1 mole of any substance contains the Avogadro's number of particles.
This amount of particles is given as 6.02 x 10²³; the particles can be protons, neutrons, electrons e.t.c.
To find the number of moles;
Number of moles = 
Through this, we clearly ascertain the number of entities in a sample given the mass.
Answer:it is 3 just look at the middle numbers
Explanation:
"<span>Changes of state are physical changes. They occur when matter absorbs or loses energy. Processes in which matter changes between liquid and solid states are freezing and </span>melting<span>. Processes in which matter changes between liquid and gaseous states are vaporization, evaporation, and condensation."</span>
Answer:
The partial pressure of argon in the jar is 0.944 kilopascal.
Explanation:
Step 1: Data given
Volume of the jar of air = 25.0 L
Number of moles argon = 0.0104 moles
Temperature = 273 K
Step 2: Calculate the pressure of argon with the ideal gas law
p*V = nRT
p = (nRT)/V
⇒ with n = the number of moles of argon = 0.0104 moles
⇒ with R = the gas constant = 0.0821 L*atm/mol*K
⇒ with T = the temperature = 273 K
⇒ with V = the volume of the jar = 25.0 L
p = (0.0104 * 0.0821 * 273)/25.0
p = 0.00932 atm
1 atm =101.3 kPa
0.00932 atm = 101.3 * 0.00932 = 0.944 kPa
The partial pressure of argon in the jar is 0.944 kilopascal.
Answer is: 2. atomic number.
Atomic number is unique and defines an element. Atomic number (Z) is total number of protons in an atom.
For example, nitrogen atom (N-14) has 7 protons (p⁺), 7 electrons (e⁻) and 7 neutrons (n°). Protons (positive charge) and neutrons are in the nucleus of atom, electrons (negative charge) are bound to the nucleus in spherical shells. Nitrogen is an element with atomic number 7. Mass number (A) is the total number of protons and neutrons in a nucleus. Nitrogen mass number is 14 (A = p⁺ + n°; A = 14).
