Answer: They are typically smaller than spiral galaxies.
Some show evidence for prior collision or close encounter with another galaxy.
They exhibit vigorous star-forming activity.
Irregular galaxies are typically smaller than spiral or normal ellipticals, of irregular form, and without spiral arms. Irr I galaxies are often characterized by lots of gas, dust, and associated star formation. Irr II galaxies have forms that indicate prior collisions or close encounters with other galaxies. Irregular galaxies are one of the most common types of galaxies.
C number of particles dissolved
Answer:
1. 3.70 g Na₂CO₃·10H₂O
2. 50.0 mL of the first solution
Explanation:
1. Prepare the solution
(a) Calculate the molar mass of Na₂CO₃·10H₂O

The molar mass of Na₂CO₃·10H₂O is 286.15 g/mol.
(b) Calculate the moles of Na₂CO₃·10H₂O

(c) Calculate the mass of Na₂CO₃·10H₂O

2. Dilute the solution
We can use the dilution formula to calculate the volume needed.
V₁c₁ = V₂c₂
Data:
V₁ = ?; c₁ = 0.0500 mol·L⁻¹
V₂ = 100 mL; c₂ = 0.0250 mol·L⁻¹
Calculation:

Answer:
A = Molarity = 0.22 M
B = Molarity = 0.36 M
Explanation:
Given data:
For first solution:
number of moles = 0.550 mol
Volume of solution = 2.50 L
Molarity = ?
Molarity:
Formula:
Molarity = number of moles of solute / volume of solution in L.
Molarity = 0.550 mol / 2.50 L
Molarity = 0.22 M
For second solution:
Mass of NaCl = 15.7 g
Volume of solution = 709 mL or 709/1000 = 0.709 L
Molarity = ?
Solution:
Number of moles = mass / molar mass
Number of moles = 14.7 g/ 58.44 g/mol
Number of moles = 0.252 mol
Molarity:
Molarity = number of moles of solute / volume of solution in L.
Molarity = 0.252 mol / 0.709 L
Molarity = 0.36 M
Answer:
- <u>Option b. Atom P has an estimated Zeff of 7 and is therefore to the right of Atom Q, which has a Zeff of 6.</u>
Explanation:
Please, find attached the figures of both atom Q and atom P corresponding to this question.
The <u>features of atom Q are</u>:
- Each <em>black sphere</em> represents an electron
- In total this atom has 8 electrons: 2 in the inner shell and 6 in the outermost shell.
- Since it is assumed that the atom is neutral, it has 8 protons: one positive charge of a proton balances one negative charge of an electron. Thus, the atomic number of this atom is 8.
- Since only two shells are ocuppied, you can assert that the atom belongs to the period 2 (which is confirmed looking into a periodic table with the atomic number 8).
- <em>Zeff </em>is the effective nuclear charge of the atom. It accounts for the net positive charge the valence electrons experience. And may, in a very roughly way, be estimated as the number of protons less the number of electrons in the inner shells. Thus, for this atom, an estimated Z eff = 8 - 2 = 6.
The <u>features of atom P</u> are:
- Again, each black sphere represents an electron
- In total this atom has 9 electrons: 2 in the inner shell and 7 in the outermost shell.
- Since it is assumed that the atom is neutral, it has 9 protons.
- The atomic number of this atom is 9.
- Using the same reasoning used for atom Q, this atom is also in the period 2.
- Estimated Z eff = 9 - 2 = 7.
Then, since atom P has a greater Z eff than atom Q (an estimated Zeff of 7 for atom P against an estimated Z eff of 6 for atom Q), and both atoms are in the same period, you can affirm that <em>atom P</em> has a greater atomic number and<em> is therefore to the right of atom Q</em>.