Which is a function of cyclins? Cyclins are carbohydrates that regulate DNA replication during the mitosis phase of the cell cycle. Cyclins are glycoproteins that repair DNA in the beginning of cell cycle. Cyclins are proteins that regulate when and how often a cell divides.
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MATCH THE FOLLOWING!!!(match each instrument with its description)1. weather maps/satellite 2. Doppler radar 3. radiosonde 4. wind vane 5. psychrometer __________________________________________________________________________A. uses two thermometers; a dry and wet bulb B. points in the direction winds are coming from C. uses frequency waves to track particle movement D. used to help track air masses and fronts E. carried with a weather balloon
1. Mendeleev organized elements in his periodic table in order of increasing ____________________. 2. You are given the melting points of three unknown substances and are asked to predict which one is an ionic compound. You would select the compound with the ____________________ melting point. 3. Two factors that determine whether a molecule is polar are the types of atoms in the molecule and the ____________________ of the molecule. 4. According to John Dalton’s observations, when elements combine in a compound A. The ratio of their masses is always the same. B. Each element contributes an equal number of atoms. C. Their volumes are always equal. D. Their masses are always equal. 5. Democritus thought that matter was made of tiny particles A. Of earth, air, fire, and water. B. That could not be divided. C. That could be divided. D. That were all round and smooth 6. Rutherford’s gold foil experiment provided evidence for which of the following statements? A. Negative and positive charges are spread evenly throughout an atom. B. Alpha particles have a positive charge. C. Gold is not as dense as previously thought. D. There is a dense, positively charged mass in the center of an atom. 7. Which statement about subatomic particles is true? A. Protons, neutrons, and electrons all have about the same mass. B. Unlike protons or neutrons, electrons have no mass. C. Neutrons have no charge and no mass. D. An electron has far less mass than either a proton or neutron. 8. Which statement is true about oxygen-17 and oxygen-18? A. They do not have the same number of protons. B. Their atoms have an identical mass. C. They are isotopes of oxygen. D. They have the same mass number. 9. Which statement accurately represents the arrangement of electrons in Bohr’s atomic model? A. Electrons vibrate in fixed locations around the nucleus. B. Electrons travel around the nucleus in fixed energy levels with energies that vary from level to level. C. Electrons travel around the nucleus in fixed energy levels with equal amounts of energy. D. Electrons travel randomly in the relatively large space outside the nucleus. 10. What does the electron cloud model describe? A. The most likely locations of electrons in atoms B. The precise locations of electrons in atoms C. The number of electrons in an atom D. The mass of the electrons in an atom 11. What is the difference between an atom in the ground state and an atom in an excited state? A. The atom in the ground state has less energy and is less stable than the atom in an excited state. B. The atom in an excited state has one fewer electron than the atom in the ground state. C. The atom in an excited state has more energy and is less stable than the atom in the ground state. D. The atom in an excited state has one more electron than the atom in the ground state. 12. The usefulness of Mendeleev’s periodic table was confirmed by A. the discovery of subatomic particles. B. its immediate acceptance by other scientists. C. the discovery of elements with predicted properties. D. the discovery of the nucleus. 13. Atoms of the most reactive elements tend to have A. one or seven valence electrons. B. eight valence electrons. C. four or five valence electrons. D. no valence electrons.
Name two compounds in unpolluted air?
Which of the following characteristics is not a property of an acid? Has a sour taste Accepts an H+ ion in reaction May cause damage to buildings, statues, and rivers Increases the concentration of hydronium ions in an aqueous solution
b)add a catalyst
c)increase the surface area
d)All of the choices are correct.
e)None of the choices are correct.
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I hope this helps. Let me know in the comments if anything is unclear.
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Answer:
Synchronous rotation is the result of tidal forces that over time slow the rotation of the smaller body until it is synchronized with its period of revolution around the larger body.
Explanation:
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Answer:
Explanation:
The best choice to prepare a buffer of pH 9.0 is a conjugate acid/base pair in which the acid has pKₐ = 9.0 ± 1.
Let's examine each of the choices.
A. NH₃/NH₄Cl
For NH₃, = pK_b = 4.75
For NH₄⁺, pKₐ 14.00 - 4.75 = 9.25
B. HCHO₂/NaCHO₂
For HCHO₂, pKₐ = 3.74
C. C₅H₅N/ C₅H₅NHCl
For C₅H₅N, = pK_b = 8.76
For C₅H₅N⁺, pKₐ 14.00 – 8.76 = 5.21
D. HNO₂/NaNO₂
For HNO₂, pKₐ = 3.33
The only acid with a pKₐ close to 9.0 is the ammonium ion.
The best buffer to prepare a buffer with pH 9.0 is
From the given options, the best combination to prepare a buffer with a PH of 9.0 is given by;
Option 1; NH₃;NH₄Cl
- A buffer solution is defined as an aqueous solution that consists of a mixture of a weak acid and its conjugate base or mixture of a weak base and its' conjugate acid.
Now, we want to find the best choice to prepare a buffer of pH 9.0. Thus, let us look at each option;
Option 1; NH₃;NH₄Cl
We are given that pK_b for NH₃ is 4.75
Thus pKₐ for NH₄ is;
NH₄; pKₐ = 14.00 - 4.75
NH₄; pKₐ = 9.25
Option 2; HCHO₂; NaCHO₂
We are given that pK_a for HCHO₂ is 3.74
HCHO₂; pKₐ = 3.74
Option 3;C₅H₅N; C₅H₅NHCl
We are given that pK_b for C₅H₅N is 8.76
Thus
For C₅H₅N, = pK_b = 8.76
Thus, pKₐ for C₅H₅N is;
C₅H₅N; pKₐ = 14.00 – 8.76
C₅H₅N; pKₐ = 5.21
Option 4; HNO₂;NaNO₂
We are given pKₐ for HNO₂ as 3.33
HNO₂; pKₐ = 3.33
Looking at all the pKₐ values, the only acid that has a pKₐ close to 9.0 is NH₄ with a pKₐ of 9.25.
In conclusion, the best combination to prepare a buffer with pH of 9.0 is
NH₃;NH₄Cl
Read more at; brainly.com/question/15592723
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Answer:
λ = 0.0167 m = 16.7 mm
Explanation:
The wavelength of these radio waves can be found out by using the formula for the speed of radio waves:
v = fλ
where,
v = speed of radio waves = speed of light = 3 x 10⁸ m/s
f = frequency of radio waves = 18 GHz = 18 x 10⁹ Hz
λ = Wavelength = ?
Therefore,
3 x 10⁸ m/s = (18 x 10⁹ Hz)λ
λ = (3 x 10⁸ m/s)/(18 x 10⁹ Hz)
λ = 0.0167 m = 16.7 mm
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Explanation:
Hydrogen atoms of one water molecule are attracted towards the oxygen atom of a neighboring water molecule can be termed as an intramolecular bond.
Generally, the oxygen atom is partially negatively charged, and the hydrogen atom is partially positively charged, so an arttraction occurs which forms this hydrogen bond. The attraction of the O-H bonding electrons towards the oxygen atom leaves a deficiency on the far side of the hydrogen atom relative to the oxygen atom. The result is that the attractive force between the O-H hydrogen and the O-atom of a nearby water molecule is strong.