# Regents Review Class No slacking today. Soon, but not yet.

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Regents Review Class No slacking today. Soon, but not yet.

A hunk of metal is 34.60 grams in mass, and using the displacement method, you calculate the volume to be 4.84 mL. What metal is it? What is the density of this metal, to the correct number of significant figures? It’s a hot one, the thermometer says 28.0°C! Convert that to Kelvin with a formula!

A hunk of metal is 34.60 grams in mass, and using the displacement method, you calculate the volume to be 4.84 mL. What metal is it? What is the density of this metal, to the correct number of significant figures? It’s a hot one, the thermometer says 28.0°C! Convert that to Kelvin with a formula! Density = Mass Volume = 34.60 g 4.84 cm 3 = 7.15 g/cm 3 with 3 SF Table S says Chromium K = C + 273 K = 28.0 + 273 = 301 Kelvin

What does TOPIC-B stand for? How many p +, n °, and e ― are in an isotope of Sr-89? Is melting of ice a chemical or physical change? Do you use chemical or physical means to separate mixtures? What is the “one liner” you need to remember as to how to separate mixtures apart?

What does TOPIC-B stand for? Indicators of chemical reactions are temperature change, odor change, irreversibility, color change, and new bubbles. How many p +, n °, and e ― are in an isotope of Sr-89? Mass is 89, Sr has 38 p + and 38 e ― and 89-38 = 51 n ° Is melting of ice a chemical or physical change? Physical Do you use chemical or physical means to separate mixtures? Mixtures are physically mixed, so use physical means only. What is the “one liner” you need to remember as to how to separate mixtures apart? You separate mixtures by taking advantage of a difference in physical properties, such as a BP difference, or FP difference, or solubility difference, or a magnetism difference, or particle size difference, etc.

Name three physical properties of water. Draw a Lewis dot diagram for methane, carbon dioxide, and magnesium oxide. Explain the models of the atoms: Democritus, Dalton, Thompson, Rutherford, Bohr, and the modern or wave mechanical models.

Name three physical properties of water. Colorless, odorless, tasteless, does not conduct electricity, FP = 0°C, BP = 100°C, density = 1.0 g/mL. Draw a Lewis dot diagram for methane, carbon dioxide, and magnesium oxide. [Mg] +2 [ O ] -2 Explain the models of the atoms: Democritus, Dalton, Thompson, Rutherford, Bohr, and the modern or wave mechanical models. Democritus said atomos, the indivisible particle. Dalton came up with atomic theory, basically atoms combined in simple whole number ratios to form compounds (etc.) His atom model was the billiard ball model, Thompson discovered the electron and created the plum pudding model. Rutherford’s gold foil experiment showed the electrons flying around a dense positive nucleus. Bohr put the electrons into orbits, not willy nilly. The orbits were energy levels (spectra detailed here too), then the wave mechanical models has electrons in orbitals or zones, and electrons act both as particles and as waves of energy at the same time (funky do).

Explain what Rutherford’s gold foil experiment showed, and how he put it all together. How did Bohr save his teacher?

All of Rutherford’s flying electrons should crash into the nucleus since flying would use up their energy, and then once slowed down, the pull inward would crash them into the nucleus. They don’t do this, but the main man could not figure this out. Niels Bohr figured the math for hydrogen and “proved” that electrons are fast enough to fly, stay in “orbits” (wrong) that somehow math-wise let them NOT lose energy, and therefore stay in orbits like they do. No one since has been able to do the math for even little helium, but since all the atoms seem to have flying electrons all the time, in orbits, (now orbitals), we just agree that Bohr was correct but it’s the math that’s too hard.

Explain the main differences between ionic and covalent bonding. Give several examples of both of these types of bonding.

Ionic bonding occurs between metals and non metals that involves a perfect transfer of electrons from the metal (now a cation) to the nonmetal (now an anion). The electrons must be exactly traded, and the ions are attracted due to crazy opposite charges. These are the strongest of all bonds. NaCl, MgO, CaBr 2, K 3 P

Covalent bonds are when 2 or more nonmetals bond together by sharing electrons. All atoms try to get an octet (unless too small like H). These bonds can be nonpolar (no Electronegative difference), or polar (EN difference). These bonds can be single, double or triple, depending upon how many electrons are being shared. One electron each (1 pair) is a single bond. HCl, H 2 O 2 electrons from each atom is a double bond (2 pairs of electrons), O 2 3 electrons from each atom is a triple bond (3 pairs of electrons). N 2

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How many electrons in an atom of tantalum, and what is the ground state electron configuration? Name another configuration of the atom is excited. Explain how metals conduct electricity, are malleable an ductile. (it’s the bonding) Why do some transitional metals make more than one cation? What are the possible cations for Mn? Write formulas and names for all the manganese chlorides

How many electrons in an atom of tantalum, and what is the ground state electron configuration? Name another configuration of the atom is excited. 73. Ground: 2-8-18-32-11-2 Excited: 2-8-18-32-10-3 Explain how metals conduct electricity, are malleable an ductile. (it’s the bonding) Metals are thought to be a lump of cations surrounded by a sea of loose, valence electrons. These electrons move when the metal shape changes, and flow when more electrons are pushed from one side (electricity). Why do some transitional metals make more than one cation? What are the possible cations for Mn? Because they can. Mn makes a +2, +3, +4 and +7 cations Write formulas and names for all the manganese chlorides MnCl 2, MnCl 3, MnCl 4, and MnCl 7. manganese (II) chloride, Manganese (III) chloride, Manganese (IV) chloride, and manganese (VII) chloride.

Write the formulas for these three compounds all with polyatomic ions, and decide if they make aqueous solutions. Ammonium phosphate lithium dichromate Lead (II) sulfate

Write the formulas for these three compounds all with polyatomic ions, and decide if they make aqueous solutions. Ammonium phosphate (NH 4 ) 3 PO 4(AQ) lithium dichromate Li 2 Cr 2 O 7(AQ) Lead (II) sulfate PbSO 4(S)

You find a balloon that is stamped 43.5 liters of argon gas at STP. What is the mass of this gas, what is the number of atoms (or are they molecules or even FU’s?)

43.5 L Ar 1 x 1 mole Ar 22.4 L Ar = 1.94 moles Argon 1.94 moles Ar 1 x 6.02 x 10 23 atoms Ar 1 mole Ar = 11.7 x 10 23 = 1.17 x 10 24 atoms Ar 3 SF, and they are ATOMS

It’s your lucky day, you find more stuff. This time it’s a container that says inside is 2.25 moles of tin. What’s the mass?

2.25 moles Sn 1 x 119 grams Sn 1 mole Sn = 267.75 g = 268 gm Sn with 3 SF

Write the chemical formulas and the empirical formulas for glucose, octane, and 1-butene

C 6 H 12 O 6 CH 2 O C 8 H 18 C 4 H 9 C 4 H 8 CH 2

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