If you cannot get a chair to move across the floor, it is because ___ friction opposes your push.

Bohr's Diagram primely illustrates an atom's unique arrangement of electrons, protons, and neutrons. Specifics of the diagram like the number and arrangement of electrons in the shells would let us identify which atom it refers to.

Without the preceding information showing the Bohr's diagram, it's truly impossible to pinpoint which specific atom it represents. A Bohr's diagram typically includes a central nucleus, denoting protons and neutrons, with surrounding energy levels or shells that signify electrons. Each atom has a unique arrangement of electrons, so the specific makeup of the diagram would determine which atom it's representing. For instance, Hydrogen, the simplest atom, would have a diagram with 1 electron at its outermost shell whereas Carbon would have 6 electrons spread across two energy levels. Please provide the details of the diagram for more specific identification.

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Answer is: helium.

Nuclear reaction is in the inner core of the Sun and hydrogen is conveted into helium.

The inner core is the central region of the Sun and all solar energy is produced in the core by nuclear fusion.

The Sun interior is divided into three regions: the inner core, the radiative zone and the convection zone.

Helium (symbol: He) is an element with atomic number 2 (2 protons) and mass number 4 (2 neutrons; n° = 4 - 2 = 2).

The answer is D. weathering and erosion of rocks

Final answer:

To find the number of oxygen atoms in 1.40 g of quartz, calculate the number of moles of quartz and use Avogadro's number to convert to oxygen atoms, accounting for two oxygen atoms per mole of SiO₂.

Explanation:

To determine how many oxygen atoms are in 1.40 g of quartz (SiO₂), we need to perform a series of calculations using the molar mass of quartz and Avogadro's number. First, we find the molar mass of quartz by adding the molar mass of silicon (28.085 g/mol) and twice the molar mass of oxygen (2 × 15.999 g/mol), which equals 60.083 g/mol. Next, we calculate the number of moles of quartz in 1.40 g using the molar mass:

Number of moles of SiO₂ = 1.40 g / 60.083 g/mol

Finally, since each mole of SiO₂ contains two moles of oxygen atoms, we use Avogadro's number (6.022 × 10²³ atoms/mol) to find the total number of oxygen atoms:

Number of oxygen atoms = Number of moles of SiO₂ × 2 × Avogadro's number

Completing the calculations provides the answer to how many oxygen atoms are in 1.40 g of quartz.

Answer:

Diamond

Explanation:

The speed of sunlight depends upon the refractive index of the medium, Diamond has the highest refractive index.

it is (#1 fire hazard

The elements in a given period (horizontal row) have the same number of electron shells in their atoms.

The horizontal row in the modern periodic table is called period. All elements placed in a period have the same number of electron shells. Each next element in a period exceed one proton and so has less metallic character than its precursor.

The atomic number increases on moving left to right in a period that tells that number of electrons and protons increases in an atom. As in a period, elements have filled the same electron shells, but an increase in the number of electrons in the same shell causes an increase in the effective nuclear charge. Therefore, the atomic radius of an atom of the elements decreases in a period.

Therefore, the elements in the same period have the same number of electron shells. For example, all elements of the second period have only two electron shells.

Learn more about periods, here:

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The angular momentum quantum number l = 2 corresponds to 5 possible values for the magnetic quantum number m, which are -2, -1, 0, 1, and 2.

For the angular momentum quantum number,
l = 2, the number of possible values for the magnetic quantum number (m) is given by the formula 2l + 1. Plugging in
l = 2, we get 2(2) + 1 = 5 possible values.

Therefore, the values of m that are possible for
l = 2 are -2, -1, 0, 1, and 2, which confirms that there are 5 possible values for the magnetic quantum number when l is 2.

The red color in a lithium salt flame test is due to electrons returning to lower energy states, emitting light at specific wavelengths. This is part of the atomic emission spectrum of lithium, with each metal displaying a unique flame color when heated.

The red color produced in a flame test when a lithium salt is subjected to heat is due to the electrons in the excited lithium atoms returning to lower energy states within the atoms. This phenomenon is a part of the atomic emission spectrum of lithium. When the lithium atoms in the flame are heated, their electrons are excited to higher energy levels. As the electrons fall back down to their original energy states, they emit light of specific wavelengths. The characteristic red color observed is due to this emission corresponding to the particular energy gap between the excited and ground states of the lithium electron.

Flame tests are commonly used to identify the presence of certain metal ions in compounds. Each metal emits a distinct color when burned, as the emission spectrum of each element is unique. For instance, sodium produces a bright yellow flame, and potassium produces a lilac color. In the context of lithium, the emission results in a bright, crimson flame, which is indicative of lithium's presence in the sample tested.

Final answer:

An oxygen molecule (O₂) has a mass of 32, whereas a chlorine molecule (Cl₂), taking into account the natural abundances of Cl-35 and Cl-37, has an average mass of approximately 70.9. Thus, chlorine has a greater mass than oxygen.

Explanation:

The student asked whether oxygen has a greater mass than chlorine. When comparing the masses of these elements, it's essential to consider the mass of their most common isotopes. Oxygen has a common isotope of oxygen-16 with a mass number of 16, while chlorine has two common isotopes, chlorine-35 with a mass number of 35 and chlorine-37 with a mass number of 37. Therefore, an oxygen molecule (O₂), which contains two oxygen atoms, has a mass of 32, while a chlorine molecule (Cl₂) would on average weigh approximately 35.5 times two due to the natural abundance of its isotopes, making it about 70.9.

This indicates that a molecule of chlorine has a greater mass than a molecule of oxygen. However, solubility of these gases in various solvents can also be related to molecular size and interactions, such as dispersion forces and dipole-dipole attractions. For example, oxygen's solubility in hexane is significantly greater than its solubility in water, illustrating the effect of these interactions on solubility.

Easy, its vertical :3

Answer: ∠2 and ∠4 are vertical angles.

Explanation: We are given two linear lines that intersect each other and forms angles.

Theorem: When two lines intersect, the vertical angle are congruent to each other which means that the two angles are equal. Vertical angles are the angles that are opposite to each other.

In the given figure, ∠2 and ∠4 are opposite to each other, hence they are considered as vertical angles.

∠2 = ∠4 (From above theorem)

Final answer:

Hydrogen was discovered in England by Henry Cavendish in 1766. While this discovery was unrelated to celestial observations as in the case of helium, hydrogen is the most abundant element in the universe and essential in the composition of stars.

Explanation:

The element hydrogen was discovered in England, not in the context of celestial observations but as an earthly element. The first recognized discovery of hydrogen is attributed to the English scientist Henry Cavendish in 1766. Cavendish identified hydrogen as a distinct species by performing experiments in which he reacted metals with strong acids to produce a gas. However, its importance and the role it plays in the universe were not completely understood at that time. Later discoveries, like that of helium in the sun's spectrum, showcased the extensive presence of elements like hydrogen in outer space, being central to the composition of stars like our Sun.

Although the student's question seems slightly mixed up with the discovery of helium, it provides a good opportunity to explore not only the terrestrial elements but also those found in the cosmic environment. Hydrogen is the most abundant element in the universe and plays a vital role in the constitution of stars and many compounds on Earth.

Final answer:

Dalton's atomic theory supports the law of conservation of mass by positing that atoms, the indivisible units of matter, are neither created nor destroyed during chemical reactions, ensuring mass remains constant in a closed system.

Explanation:

How does Dalton's atomic theory support the law of conservation of mass? John Dalton's atomic theory re-introduced the idea of atomism, which suggests that all matter is composed of small, indestructible units known as atoms. This theory aligns closely with the law of conservation of mass, established by Antoine Lavoisier, which states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations.

Dalton proposed that chemical reactions involve the rearrangement of atoms that are combined, separated, or rearranged, but never created or destroyed. Therefore, the total mass of reactants in a chemical reaction equals the total mass of the products. This agreement with the law of conservation of mass is a fundamental principle showing that during any chemical process in a closed system, the mass remains constant. Dalton's theory provides a microscopic explanation of this macroscopic observation, illustrating that the mass conservation is due to the conservation of atoms in chemical processes.

If an element like copper consists of only one kind of atom, it means it cannot be broken down into simpler substances. This implies that atoms, the fundamental building blocks of matter, are neither created nor destroyed during a chemical change, reinforcing the concept of mass conservation. This understanding marks a pivotal development in the field of chemistry, allowing for the quantitative study of chemical reactions and the advancement of chemical science.

The electron configuration given corresponds to Strontium (Sr), which is element number 38 on the periodic table and ends with the 5s² subshell being filled after the noble gas krypton's (Kr) electron configuration.

The element with the electron configuration 1s2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶5s² is Strontium (Sr). It is identified by examining the electron configuration and matching it to the position on the periodic table. The electron configuration ends with 5s², following the noble gas krypton (Kr), and two additional electrons in the 5s orbital indicate that we move two places beyond krypton in the periodic table. This corresponds to the element with atomic number 38, which is Strontium (Sr).

Ionization energy is the energy required to remove an electron from an atom. Meanwhile, Electron affinity is the energy required to add an electron to an atom. So we can see that the two are opposite variables. However, they both refers to general attraction of an atom for “electron”.

To find the molar mass of the gaseous compound, we used the Ideal Gas Law and calculated it to be approximately 65.65 g/mol.

The given conditions were converted and used properly to solve the problem.

Given data:

We know from the Ideal Gas Law:

Rearranging to solve for molar mass (M):

Substitute the values:

Calculate the result:

Therefore, the molar mass of the compound is approximately 65.65 g/mol.

Lewis electron dot diagrams represent valence electrons around atomic symbols, aiding in predicting bonding capabilities. Valence electrons' importance in chemical reactivity is highlighted through electron-dot symbols in Lewis diagrams.

Lewis electron dot diagrams use dots to represent valence electrons around an atomic symbol. These dots are arranged to the right and left, above, and below the symbol, indicating the valence electrons. For example, in the Lewis structure for hydrogen, it is represented by a single dot.

Valence electrons are crucial in determining an atom's reactivity and bonding capabilities. Electron-dot symbols help predict the number of bonds an element can form in a compound. In Lewis diagrams, dots represent the valence electrons, while lines denote bonds formed between atoms.

To find the H+ concentration of an ammonia solution with a pH of 9.15, we use the inverse logarithm of the negative pH value, which gives a H+ concentration of 7.08  imes 10^-10 M.

If the pH of a 0.35 M ammonia solution is 9.15, we can calculate the H+ concentration using the pH formula. The formula for pH is pH = -log[H+], where [H+] represents the concentration of hydrogen ions in moles per liter (M). To find [H+], we take the inverse logarithm (antilog) of the negative pH value:

[H+] = 10-pH

Plugging in the pH value given:

[H+] = 10-9.15 = 7.08  imes 10-10 M

Therefore, the concentration of H+ ions in the ammonia solution is 7.08  imes 10-10 M.

Answer:

best primary material for a new coin: a metal,

Explanation:

Answer:

Hydrogen fuel cells have a higher energy efficiency.

Hydrogen fuel cells create less pollution.

Explanation:

Hydrogen fuel cell is an electrochemical cell which employs hydrogen gas to produce electricity and water.In this cell chemical energy of hydrogen gas is converted into electrical energy.

Advantages of hydrogen fuel cell: