Heat energy is always released during what type of process?
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Related Questions
how many milliliters of 1.50 m hno3 contain enough nitric acid to dissolve an old copper penny with a mass of 3.94 g?
How many atoms of oxygen in this equation : 3Ni(OH)2
Hich one of the following is radical?(1 Point)a.NH4+b. CuSO4c. CH4d. NH3
What is the percentage of water to the nearest tenth in this compound? Ba(OH)2 * 8H2O
Which statement is true about this reaction?
(1) Each Al loses 2e- and each Cu2+ gains 3e-
(2) Each Al loses 3e- and each Cu2+ gains 2e-
(3) Each Al3+ gains 2e- and each Cu loses 3e-
(4) Each Al3+ gains 3e- and each Cu loses 2e-
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Answers
Final answer:
Among alpha,beta, neutron, and gamma radiations, gamma radiation has the greatest ability to penetrate matter. It can pass through dense and thick materials, including a few feet of concrete and even lead.
Explanation:
When comparing the ability of different types of radiation to penetrate matter, from least penetrating to most penetrating, the sequence is alpha < beta < neutron < gamma. This means the gamma radiation is the most penetrating type of radiation. Alpha radiation has the least penetration ability and can be blocked by even a thin sheet of paper. Beta radiation has slightly higher penetration power, able to go through about 3mm of aluminum, for instance. Gamma radiation, on the other hand, can penetrate much denser and thicker materials. For example, high-energy gamma radiation can pass through a few feet of concrete, and even lead to a depth of 2 or more centimeters.
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With high cholesterol, you can develop fatty deposits in your blood vessels. Eventually, these deposits grow, making it difficult for enough blood to flow through your arteries. Sometimes, those deposits can break suddenly and form a clot that causes a heart attack or stroke.
Answer:
Cholesterol is a waxy substance found in your blood. Your body needs cholesterol to build healthy cells, but high levels of cholesterol can increase your risk of heart disease.
With high cholesterol, you can develop fatty deposits in your blood vessels. Eventually, these deposits grow, making it difficult for enough blood to flow through your arteries. Sometimes, those deposits can break suddenly and form a clot that causes a heart attack or stroke.
Explanation:
High cholesterol can cause a dangerous accumulation of cholesterol and other deposits on the walls of your arteries (atherosclerosis). These deposits (plaques) can reduce blood flow through your arteries, which can cause complications, such as:
Chest pain. If the arteries that supply your heart with blood (coronary arteries) are affected, you might have chest pain (angina) and other symptoms of coronary artery disease.
Heart attack. If plaques tear or rupture, a blood clot can form at the plaque-rupture site — blocking the flow of blood or breaking free and plugging an artery downstream. If blood flow to part of your heart stops, you'll have a heart attack.
Stroke. Similar to a heart attack, a stroke occurs when a blood clot blocks blood flow to part of your brain.
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.
Answers
2. Highest melting point
3. Configuration
4. A
5. A
6. D
7. A
8. C
9. B
10. A
11. C
12. C
13. A
Final answer:
This answer explains chemical concepts related to the periodic table, atomic theory, the nature of molecules, and properties of subatomic particles.
Explanation:
1. Mendeleev organized elements in his periodic table in order of increasing atomic mass.
2. You would select the compound with the highest melting point as the ionic compound.
3. The types of atoms in the molecule and the shape of the molecule determine whether a molecule is polar.
4. According to Dalton, The ratio of their masses is always the same when elements combine in a compound.
5. Democritus thought that matter was made of tiny particles that could not be divided.
6. Rutherford’s gold foil experiment provided evidence that there is a dense, positively charged mass in the center of an atom.
7. It’s true that an electron has far less mass than either a proton or neutron.
8. Oxygen-17 and oxygen-18 are isotopes of oxygen.
9. In Bohr’s atomic model, electrons travel around the nucleus in fixed energy levels with energies that vary from level to level.
10. The electron cloud model describes the most likely locations of electrons.
11. An atom in an excited state has more energy, and is less stable than an atom in the ground state.
12. The usefulness of Mendeleev’s periodic table was confirmed by the discovery of elements with predicted properties.
13. Atoms of the most reactive elements tend to have one or seven valence electrons.
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Answers
The isotope has 27 electrons and 29 protons.
Given:
The isotope of copper with +2 charge and mass number of 65.
To find:
The number of electrons and protons in the given isotope.
Solution
The atomic number of copper = 29
Atomic number = Number of protons
Number of protons in copper atom = 29
Number of electrons in copper atom = 29
The isotope of copper=
(A neutral atom has equal number of protons and electrons)
The number of protons in isotope and in parent atom remains same.
Number of proton in = 29
Charge on the given copper's isotope ( ) = +2
Number of electrons :
= 29 - 2 = 27
(+2 charge indicates lessor two electrons out of total electrons)
The isotope has 27 electrons and 29 protons.
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29p,36n,27e
i think is the answer
(2) H2SO3(aq) and Ca(NO3)2(aq)
(3) H2SO4(aq) and Ca(OH)2(aq)
(4) SO2(g) and CaO(s)
Answers
H₂SO₄(aq) and Ca(OH)₂(aq) form the salt CaSO₄(s) in a neutralization reaction. Therefore, option C is correct.
What is a neutralization reaction?
A neutralization reaction is a chemical process in which an acid and a base combine to produce salt and water as the end products. H⁺ ions and OH⁻ ions combine to generate water during a neutralization process.
The reaction between sulfuric acid (H₂SO₄) and calcium hydroxide (Ca(OH)₂) is an acid-base neutralization reaction that produces calcium sulfate (CaSO₄) and water (H₂O) as products. The balanced chemical equation for this reaction is:
H₂SO₄(aq) + Ca(OH)₂(aq) → CaSO₄(s) + 2H₂O(l)
In this reaction, sulfuric acid donates two protons to the hydroxide ions from calcium hydroxide, forming water molecules. The remaining ions (Ca²⁺ and SO₄²⁻) combine to form the solid product, calcium sulfate. Hence, option C is correct.
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