Answer:
The molar concentration of a solution made with 3.744 g of Mg(NO₃)₂ dissolved in enough water to make 50.0 mL of solution is 
Explanation:
Molarity or Molar Concentration is the number of moles of solute that are dissolved in a certain volume.
The molarity of a solution is calculated by dividing the moles of the solute by the volume of the solution:
In this case:
- Mg: 24.3 g/mole
- N: 14 g/mole
- O: 16 g/mole
So, the molar mass of Mg(NO₃)₂ is:
Mg(NO₃)₂= 24.3 g/mole + 2*(14 g/mole + 3*16 g/mole)= 148.3 g/mole
So, if you have 3.744 g of Mg(NO₃)₂, you can apply the following rule of three: if 148.3 grams of Mg(NO₃)₂ are present in 1 mole, 3.744 grams in how many moles are present?
moles= 0.025
Then you have:
- number of moles=0.025
- volume= 50 mL= 0.05 L (being 1,000 mL= 1 L)
Replacing in the definition of molarity:
you get:
<u><em>The molar concentration of a solution made with 3.744 g of Mg(NO₃)₂ dissolved in enough water to make 50.0 mL of solution is </em></u><u><em></em></u>
Answer is: a) ionization energy and electronegativity.
1) The ionization energy (Ei) is the minimum amount of energy required to remove the valence electron, when element lose electrons, oxidation number of element grows (oxidation process).
Barium, potassium and arsenic are metals (easily lost valence electrons), chlorine is nonmetal (easily gain electrons).
Alkaline metals (far left in Periodic table) have lowest ionizations energy and easy remove valence electrons (one electron), earth alkaline metals (next right to alkaline metals) have higher ionization energy than alkaline metals, because they have two valence electrons.
Nonmetals are far right in the main group and they have highest ionization energy, because they have many valence electrons.
2) Electronegativity (χ) is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.
Atoms with higher electronegativity attracts more electrons towards it, electrons are closer to that atom.
Nonmetals hava higher electronegativity than metals and metalloids.
3) The atomic radius decreases across the periods because an increasing number of protons, because greater attraction between the protons and electrons.
Answer:
a. form a hypothesis, conduct an experiment, record data, make a conclusion
Explanation:
Performing scientific investigations involved following the SCIENTIFIC METHOD, which is a rule or guideline followed in order to discover knowledge about natural phenomena. The scientific method has been divided into steps viz:
- Making observation/asking questions: In this case, the problem is HOW ANTS FEED.
- Formulating hypothesis: The hypothesis is a testable explanation given to solve the asked question.
- Testing hypothesis: The hypothesis must be able to be tested via conducting an experiment.
- Analyze result: The results of the test is recorded and analysed as data.
- Make conclusions: The conclusion either accepts or rejects the hypothesis depending on the result of the experiment.
Therefore, based on this; form a hypothesis, conduct an experiment, record data, make a conclusion are the steps Colby should take to best study the feeding patterns of ants
<span>389.88094 amu
First we look up the atomic mass of all elements contained in calcium iodate using the periodic table:
Ca: 40.078
I: 126.90447
O: 15.999
As an intermediate step we calculate the molecular mass of the ion IO3:
126.90447 + 3*15.999 = 174.90147
Then we calculate the mass of one calcium atom and 2 iodate ions:
2*174.90147 + 40.078 = 389.88094 amu</span>
I think it is b. Ga, Ge, As, Se
