A sample of 254.2 grams of copper completely reacted with oxygen to form 286.2 grams of a copper oxide product. how many grams of oxygen must have reacted?
Final answer:
To calculate the grams of oxygen that reacted, subtract the mass of copper (254.2 grams) from the mass of the copper oxide product (286.2 grams) to get 32.0 grams of oxygen.
Explanation:
To find out how many grams of oxygen reacted with copper to form copper oxide, perform a mass difference calculation from the given data. The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction. Therefore, the mass of products formed in a reaction equals the mass of reactants.
The initial mass of copper is given as 254.2 grams, and the final mass of the copper oxide product is 286.2 grams. To find the mass of oxygen that has combined with the copper, subtract the mass of copper from the mass of the copper oxide product:
Mass of oxygen = Mass of copper oxide – Mass of copper
Mass of oxygen = 286.2 grams – 254.2 grams
Mass of oxygen = 32.0 grams
Therefore, 32.0 grams of oxygen must have reacted with the copper.
What is the process by which molecules of water vapor in the air become liquid water?
Is adding hot cocoa to hot water a chemical or physical change?
Adding hot cocoa to water is a physical change because it involves combining substances without changing their chemical compositions.
Adding hot cocoa to hot water is considered a physical change. When you mix hot cocoa powder with hot water, the hot cocoa dissolves and the two substances combine, but this process does not result in new chemical substances being formed. Just like other physical changes such as the melting of ice or the dissolving of sugar in water, the composition of the resulting mixture is still a combination of water and cocoa particles.
In contrast, a chemical change involves a substance transforming into a new substance with a different chemical composition, as exemplified by iron rusting (Fe + O₂ → Fe₂O₃) or the burning of gasoline.
A pill claims that it stops acne. A label on the bottle reads: "This product has not been tested by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease." What can you conclude about this product?
A. There is little evidence for this claim
B. There is no known treatment for acne
C. This product is made by doctors
D. This product will stop acne
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The relative atomic mass of an atom can be found by comparing the mass of the atom to the mass of
The relative atomic mass of an atom is found out by comparing the mass of the atom to the mass of an atom of carbon-12.
What is an atom?
An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
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(true or false) the electron structure of an atom is determined by direct observation using x-rays.
The answer is false. It is because the electron structure of the atom is not determined by using the direct observation of using an x-ray but rather the usage of theoretical modeling and the emission spectra will be useful in observing.
Why are tin granules used instead of just a piece of tin?
The reason why Tin granules is mostly used or preferred than just a piece of Tin because a piece of Tin is plainly metal, in which this will be difficult in having it to be oxidized when it is exposed or in the air rather than Tin granules.
Answer:
To increase the surface area of reaction.
Explanation:
The tiny granules are used as they increase the surface-area to volume ratio. Smaller granules have a higher surface area to volume ratio. In a chemical reaction, it means that the reaction increases as there is more particle to particle reaction.
Hence the granules are preferred to solids.
convert 1.5 km to millimeters, and express the result in scientific notation.
When magnesium reacts with chlorine, magnesium ions (mg 2 ) and chloride ions (cl−) are formed. in this reaction, magnesium atoms?
What chemical property is most commonly used to classify igneous rocks?
Actually Igneous rocks are classified either based on grain size or based on mineralogy. However grain size is clearly not a chemical property. So we can say that they are classified chemically based on mineralogy or the abundance of quartz or silica present.
How many atoms are in 3.08 mol of pure aluminum?
To determine the number of atoms in 3.08 mol of pure aluminum, multiply the number of moles by Avogadro's number.
In order to determine the number of atoms in 3.08 mol of pure aluminum, we need to use Avogadro's number. Avogadro's number is a fundamental constant in chemistry that represents the number of atoms or molecules in one mole of a substance. It is approximately equal to 6.022 × 10²³ atoms/mol.
To find the number of atoms in 3.08 mol of pure aluminum, you can use the following calculation:
Multiply the number of moles (3.08 mol) by Avogadro's number (6.022 × 10^23 atoms/mol):Number of atoms = 3.08 mol × (6.022 × 10²³ atoms/mol)
By performing this calculation, you will find the number of atoms in 3.08 mol of pure aluminum.
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________ processes such as evaporation and chemical activity can precipitate chemical sediments.
What are the general properties of the elements in the group to the right in the modern periodic table?
The general properties of the elements to the right in the modern periodic table are low melting and boiling point, high ionization energy, high electron affinity, poor conductor, and lack of metallic luster.
What are nonmetals?The elements present on the right-hand side of the modern periodic table are nonmetals. Nonmetals are the elements that form negative ions by gaining electrons and have 4, 5, 6, or 7 electrons in their outermost shell.
Non-metals lack all metallic attributes and are good insulators of heat and electricity. They are generally gases at room temperature and sometimes liquid.
Nonmetals are high ionization energies and high electronegativity so they gain electrons when reacting with other compounds, to form covalent bonds.
Nonmetals have high electronegativities so they have a strong tendency to attract electrons. Nonmetals exist as liquids or gases therefore, they have low melting and boiling points under normal conditions.
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A student cleaned a crucible with hcl. after pouring the hcl into the waste container, the crucible was neither rinsed with water nor dried before the student added the nahco3-nacl mixture. the crucible contained some residual hcl. how would this affect the calculated percentage of nahco3 in the mixture
Presence of residual HCl will react with [tex]NaHCO_3[/tex], reducing its amount and thus lower the calculated percentage of [tex]NaHCO_3[/tex] in the mixture.
If a student cleaned a crucible with HCl and then added a [tex]NaHCO_3[/tex]-NaCl mixture without rinsing or drying it, this would affect the calculated percentage of [tex]NaHCO_3[/tex] in the mixture due to the reaction between the residual HCl and [tex]NaHCO_3[/tex]. Specifically, HCl is an acid which would react with [tex]NaHCO_3[/tex], a base, to produce NaCl, [tex]CO_2[/tex], and [tex]H_2O[/tex].
[tex]NaHCO_3[/tex] (s) + HCl (aq) → NaCl (aq) + [tex]CO_2[/tex] (g) + [tex]H_2O[/tex] (l)
This reaction would decrease the amount of [tex]NaHCO_3[/tex] in the crucible, leading to a lower calculated percentage of [tex]NaHCO_3[/tex] in the mixture than actually present. This is because the [tex]CO_2[/tex] produced escapes as a gas, reducing the mass that is attributed to [tex]NaHCO_3[/tex].
Explain in terms of both electrons and energy how the bright line spectrum of an element is produced
Bright line spectrum is produced when electrons within an atom transition from higher energy level to lower one, emitting light at distinct wavelengths. These distinct wavelengths constitute the emission lines forming the bright line spectrum.
Each element has a unique set of such energy levels, allowing the identification of specific elements.
Explanation:The bright line spectrum of an element is produced when electrons in an atom absorb energy and move from a lower energy level to a higher one, a state known as excited state. As these electrons transition back to their original or lower energy level, they emit energy in the form of light, which is at distinct wavelengths.
These distinct wavelengths appear as a series of lines in a spectrograph, known as emission lines, and they form the bright line spectrum of an element as each element possesses its own unique set of energy levels. An understanding of such spectral lines allows us to identify specific elements present in the stars and other celestial bodies.
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The bright line spectrum of an element is produced by the emission of photons when electrons transition from higher energy levels to lower ones. Each element has its own unique set of energy levels, resulting in a distinct pattern of spectral lines.
Explanation:The bright line spectrum of an element is produced by the emission of photons when electrons transition from higher energy levels to lower ones. Each element has its own unique set of energy levels, resulting in a distinct pattern of spectral lines. When an electron absorbs a photon and moves to a higher energy level, absorption lines are observed. These spectral lines allow scientists to identify the elements present in a substance.
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What caused the deflection of the alpha particles in rutherford's gold foil experiment?
The deflection of alpha particles in Rutherford's gold foil experiment was caused by the presence of a dense, positively charged nucleus within the atom that repelled the positively charged alpha particles.
Explanation:The deflection of the alpha particles in Rutherford's gold foil experiment is attributed to the presence of a dense, positively charged center or 'nucleus' in the atoms. Alpha particles, which are helium atoms that have lost their electrons and are therefore positively charged, were fired at a thin piece of gold foil. The majority of these alpha particles passed through the gold foil, suggesting that the atoms consist mostly of empty space.
However, a small fraction of the alpha particles were significantly deflected or even completely reversed direction. This indicates that these particles encountered a highly concentrated positive charge (the nucleus of the atom) that repelled the like-charged alpha particles. This deflection allowed Rutherford to deduce the presence of a small, dense nucleus within the atom, contradicting the then-established 'plum pudding' model of atom structure.
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Complete ground state electron configuration for the aluminum atom
true or false elements in the same colum have simular properties
Answer: true because they have similar chemical properties
Explanation:
Because Elements present in the same group have the same number of valence electrons.
A group of scientists is trying to launch an object into orbit, and the object is traveling at 6500 m/s. Which best explains why the object will not successfully orbit Earth?
Answer:
The object is not traveling fast enough to match Earth’s curvature.
Explanation:
c on edge
Which type of observation involves exact measurement, quantitative or qualitative?
Answer:
1. Quantitative
2. Qualitative
3. Qualitative
Explanation:
In the redox titration of Fe2+ with Ce4+ to form Fe3+ and Ce3+ what is the predominant form of cerium after 120 ml of Ce4+ has been added to the Fe2+ solution?
A.) Ce1+
B.) Ce2+
C.) Ce3+
D.) Ce4+
Actually the answer to this problem primarily depends on how much Fe2+ is initially contained in the solution. So if in case it contains more or equal amount than the cerium solution, then the answer is C. But if it has much less, then it would be D.
But I believe the answer in this case is:
C
Answer:
Ce+3
Explanation:
Use quantum numbers to represent the locations of electrons.
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Which regions on the periodic table can adopt positive and negative oxidation numbers?
The region(s) of the periodic table which are made up of elements that can adopt both positive and negative oxidation numbers are the “non-metal” region. As we can see on the periodic table, the elements situated at the right side of the table have two oxidation states, one positive and the other a negative.
A system used to represent the valence electrons around the chemical symbol of an element is the
Answer:
Lewis Dot Diagram
Explanation:
The element that is shiny in appearance quite dense and liquid at room temperature is
Which substance has polar covalent bonds? which substance has polar covalent bonds? n2 bao f2 so2?
Fluorine and Nitrogen are both non-metals which posses non polar covalent bonds. BaO on the other hand is a combination of a metal (Ba) and non metal (O) hence making it an ionic bond. So in this case, only SO2 has polar covalent bond.
Answer:
SO2
Sulfur dioxide (SO2) is a substance with polar covalent bonds among the given options. It has atoms with different electronegativities, hence the unequal sharing of electrons. SO2's bent molecular shape also contributes to its overall polarity.
Explanation:The substance with polar covalent bonds among N2, BaO, F2, and SO2 is SO2 (sulfur dioxide). Polar covalent bonds occur when there is an unequal sharing of electrons between atoms with different electronegativities.
Nitrogen (N2) and Fluorine (F2) are both diatomic molecules of the same element and thus have nonpolar covalent bonds because they share electrons equally. Barium oxide (BaO) is an ionic compound because it is composed of a metal and a nonmetal.
Sulfur dioxide (SO2), on the other hand, has atoms with different electronegativities which leads to an unequal sharing of electrons and the formation of polar covalent bonds. The molecule is also bent in shape, which contributes to its overall polarity.
How could you distinguish between the gases h2 and no2?
Explanation:
A molecule is defined as a substance which contains chemically bonded same type of elements.
For example, [tex]H_{2}[/tex] is a molecule and it exists as a gas which is colorless and odorless.
Hydrogen gas is represented as [tex]H_{2}[/tex].
Whereas a compound is defined as a substance which contains chemically bonded different type of elements in a fixed ratio by mass.
For example, [tex]NO_{2}[/tex] is a compound and has a reddish brown color with toxic odor.
Nitrogen dioxide is represented as [tex]NO_{2}[/tex].
The reaction nacl(s) → nacl(aq) is performed in a coffee cup calorimeter, using 100 ml of h2o(l) and 5.00g of nacl. if the temperature of solution after mixing decreased by 2.30°c, what is the δhrxn in kj/mol? assume the heat capacities of all solutions are 4.18 j/g°c, and densities of all solutions are 1.00 g/ml. the molar mass of nacl is 58.44 g/mol
Since the density of water is 1 g /mL, hence there is 100 g of H2O. So total mass is:
m = 100 g + 5 g = 105 g
=> The heat of reaction can be calculated using the formula:
δhrxn = m C ΔT
where m is mass, C is heap capacity and ΔT is change in temperature = negative since there is a decrease
δhrxn = 105 g * 4.18 J/g°C * (-2.30°C)
δhrxn = -1,009.47 J
=> However this is still in units of J, so calculate the number of moles of NaCl.
moles NaCl = 5 g / (58.44 g / mol)
moles NaCl = 0.0856 mol
=> So the heat of reaction per mole is:
δhrxn = -1,009.47 J / 0.0856 mol
δhrxn = -11,798.69 J/mol = -11.8 kJ/mol
For an electron in an atom to change from the ground state to an excited state, energy must be
For an electron to move from its zero or ground state to an excited state of higher energy level, of course it has to absorb energy.
Just like a person, energy must be supplied so that the person will be lively or active.
Answer:
energy must be absorbed
An electron absorb energy when change from ground state to excited state.
If an electron in an atom change from the ground state to an excited state, it must be absorb energy because with the help that energy it can move against the force of attraction of nucleus of that atom.
This energy provided to electron in order to remove the electron from outermost shell of that atom. If the electron release the energy then it comes back to its original position so we can conclude that electron absorb energy when change from ground state to excited state.
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