Answer:All of them
Explanation:
Answer: The correct answer is all of them!
Explanation:
Looked at my lesson after seeing mixed answers and the correct answer is all of them!
Which one of the following is a balanced equation?
O A. 2NH3 (g) + 3Mg (s) - 3H2 (g) + Mg3N2 (s)
OB. 4NH3 (9) + Mg(s)* - H2(g) + Mg3N2 (s)
OC. NH3 (9) + Mg (s) - H2 (9) + Mg3N2 (s)
O D. Ca (s) + 02 (9) - 2Cao (s)
Answer: OA is a balanced equation.
Explanation: For an equation to be balanced, the number of atoms and the total charge of each element in the reaction, of the product and reactant side must be the same.
Considering OA; 6 atoms of nitrogen is present in the reactant side. Shifting to the product side, 6 atoms of nitrogen is also present. Taking the other element in the reaction into account, the number of atoms of each element balances on both sides.
ANSWER:
The correct answer is OA. 2NH3 (g) + 3Mg (s) →3H2 (g) + Mg3N2 (s)
The Equation; 2NH3 (g) + 3Mg (s) →3H2 (g) + Mg3N2 (s), is a balanced chemical equation.
FURTHER EXPLANATION;
According to the law of conservation of mass, all chemical equations should be written such that the mass of the reactants is equal to the mass of the products.
This is done by balancing the chemical equation.
Balancing of chemical equations is a try and error method that makes sure the number of atoms of each element in a chemical equation are equal on the side of the reactants and that of products.
The equation; 2NH3 (g) + 3Mg (s) →3H2 (g) + Mg3N2 is said to be balanced since the number of atoms of each element are equal on both side of the equation.
That is; 2 atoms of nitrogen, 6 atoms of hydrogen and 3 atoms of magnesium on both side of the equation.
Choice OB is incorrect because, the equation 4NH3 (g) + Mg(s)* - H2(g) + Mg3N2 (s) is not balanced as the number of nitrogen atoms and that of hydrogen atoms are not equal on both side of the equation.(4 nitrogen atoms on the reactant side and 2 nitrogen atoms on the product side, 12 hydrogen atoms on the reactant side and 2 hydrogen atoms on the product side).
Choice OC is incorrect because, the equation, NH3 (g) + Mg (s) - H2 (g) + Mg3N2 (s) is not balanced as the number of nitrogen atoms, magnesium atoms and that of hydrogen atoms are not equal on both side of the equation.(1 nitrogen atom on the reactant side and 2 nitrogen atoms on the product side, 3 hydrogen atoms on the reactant side and 2 hydrogen atoms on the product side, 1 magnesium atom on the reactant side and 3 magnesium atom on the product side).
Choice OD is incorrect because, the equation Ca (s) + 02 (9) - 2Cao (s) is not balanced as the number calcium atoms is not the same on both side of the equation, 1 calcium atom on the reactant side and 2 calcium atoms on the product side.
Assigning Oxidation Numbers
QUICK CHECK
What are the oxidation numbers of the atoms in this reaction?
Check all that apply.
Mg(s) + 2HCl(aq) - MgCl2(aq) + H2(g
Mg = 0
H =+1
Cl= -1
Mg= +2
Cl=-1
H= 0
Answer:
B,C,D,E
Explanation:
Edge
what amount in moles does 242 L of carbon dioxide occupy at 1.32 atm and 20 degrees C
Answer:
13.28 mol.
Explanation:
We can use the general law of ideal gas: PV = nRT.where, P is the pressure of the gas in atm (P = 1.32 atm).
V is the volume of the gas in L (V = 242.0 L).
n is the no. of moles of the gas in mol (n = ??? mol).
R is the general gas constant (R = 0.0821 L.atm/mol.K).
T is the temperature of the gas in K (T = 20.0° + 273 = 293.0 K).
∴ n = PV/RT = (1.32 atm)(242.0 L)/(0.0821 L.atm/mol.K)(293.0 K) = 13.28 mol.
During metamorphic processes, increased pressure and temperature can affect the _______ of minerals in rock. Rocks subjected to very high pressure are typically _______ than others because mineral grains are squeezed together, and the atoms are more closely packed. During metamorphic processes, water facilitates the transfer of ions between and within minerals, which can _______ the rate at which metamorphic reactions take place. The growth of new minerals within a rock during metamorphism has been estimated to be about _______ per million years. _______ metamorphism is commonly associated with convergent plate boundaries, where two plates move toward each other. During contact metamorphism, a large intrusion will contain _______ thermal energy and will cool much more slowly than a small one. Metamorphosed sandstone is known as _______. The metamorphic rock _______, made from metamorphosed shale, was once used to make blackboards for classrooms.
Answer:
1.) stability
2.) denser
3.) increase
4.) 1 millimeter
5.) regional
6.) more
7.) quartzite
8.) slate
Explanation:
Answer:
Stability , Denser, Increase, 1 millimetre, Regional, More, Quartzite, Slate
Explanation:
During metamorphic processes, increased pressure and temperature can affect the stability of minerals in rock. Rocks subjected to very high pressure are typically denser than others because mineral grains are squeezed together, and the atoms are more closely packed. During metamorphic processes, water facilitates the transfer of ions between and within minerals, which can increase the rate at which metamorphic reactions take place. The growth of new minerals within a rock during metamorphism has been estimated to be about 1 millimeter per million years. Regional metamorphism is commonly associated with convergent plate boundaries, where two plates move toward each other. During contact metamorphism, a large intrusion will contain more thermal energy and will cool much more slowly than a small one. Metamorphosed sandstone is known as quartzite. The metamorphic rock slate, made from metamorphosed shale, was once used to make blackboards for classrooms.
Which state of matter is highly compressible, is made of particles moving independently of each other, and is present in large quantities near Earth’s surface?
Answer:
GAS
Explanation:
Answer:
Gas
Explanation:
The gaseous state of matter is highly compressible. According to the kinetic theory of matter, in the gaseous state, gas molecules largely move independent of each other and experience very little intermolecular forces between them.
Gases are abundant in the atmosphere near the earth's surface.
You completed three terra-forming trials. Describe how the suns mass affects planets in a solar system. Use the data your recorded to support your conclusions
Answer:
The suns mass affects the planets in the solar system because the grater the mas the stronger the gravitaional pull so the saster the planet orbits the sun.
Explanation:
Suns mass directly affected the position of planets in the solar system.
What is the effect of mass of sun?If the mass of the Sun is increased, the Sun would exert a stronger gravitational force on materials present around it. This change in mass of sun would disturb the orbits of all of the planets, pulling them closer to it.
So we can conclude that suns mass directly affected the position of planets in the solar system.
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Consider the molecules HCl, HBr, HF, and HI. Which would you expect to have the highest boiling point, and why?
HBr, because it has the highest mass and the most electrons.
HCl, because it experiences hydrogen bonding.
HF, because it has the strongest intermolecular force.
HI, because it experiences ion-dipole forces.
Answer: A
Explanation: Boiling point increases with the rise of electrons.
Answer:
Not sure what the answer is, but it's not A.
Explanation:
Submitted the problem and A was incorrect.
Solution F has a pH of 11, and Solution G has a pH of 13.
How does the concentration of hydroxide ions in Solution F differ from Solution G?
Solution G has three times as many hydroxide ions as Solution F.
Solution G has 100 times more hydroxide ions than Solution F.
Solution F has 100 times more hydroxide ions than Solution G.
Solution F has three times as many hydroxide ions as Solution G.
Answer:
Solution G has 100 times more hydroxide ions than Solution F.
Explanation:
∵ pH + pOH = 14.
∴ pOH = 14 - pH.
For solution F:
pOH = 14 - pH = 14 - 11 = 3.
∵ pOH = -log[OH⁻] = 3.
∴ [OH⁻] = 0.001 M.
For solution G:
pOH = 14 - pH = 14 - 13 = 1.
∵ pOH = -log[OH⁻] = 1.
∴ [OH⁻] = 0.1 M.
∴ [OH⁻] of solution G / [OH⁻] of solution F = (0.1)/(0.001) = 100.
So, Solution G has 100 times more hydroxide ions than Solution F.
Which term describes something that changes during an experiment?
Answer:
Dependent variable
Explanation:
Answer:
A variable
Explanation:
A variable is data that changes, two examples are an independent variable and a dependent variable.
identify the branch of chemistry.
percentage purity of glucose.
Answer:
1. There are many branches of chemistry or chemistry disciplines. The five main branches are organic chemistry, inorganic chemistry, analytical chemistry, physical chemistry, and biochemistry.
2. 25mg
The question regarding the percentage purity of glucose falls under the domain of analytical chemistry, a branch of chemistry focused on analyzing substances to ascertain their composition and purity. It involves calculating the ratio of the pure substance's mass to the sample's total mass and converting this into a percentage.
Explanation:The question about identifying the percentage purity of glucose pertains to the branch of chemistry known as analytical chemistry. This field is crucial for quantitatively and qualitatively analyzing substances to determine their composition and purity. To find the percentage purity of a sample, one would typically use the formula:
%purity = (mass of compound / mass of sample) × 100
For instance, if you're analyzing glucose, you'll first need to determine the total mass of the glucose sample you're evaluating. After that, you conduct an experiment or analysis to ascertain the mass of pure glucose within that sample. Once you have both values, you substitute them into the equation to calculate the percent purity of the glucose. This allows chemists to ensure that the concentration of glucose or any other substance is within the required specifications for its intended use, whether that be for consumption, industrial applications, or research.
Such analysis is vital for ensuring the safety and effectiveness of products, maintaining quality control, and complying with legal standards for purity and composition.
A 5.000 g sample of Niso4 H2O decomposed to give 2.755 g of anhydrous NiSO4.
What is the formula of the hydrate?
What is the full chemical name for the hydrate?
What is the molar mass of the hydrate? NiSO4•_H2O
What is the mass % of water in the hydrate?
Answer:
a) 7.0.
b) Nickel sulfate hepta hydrate.
c) 280.83 g/mol.
d) 44.9%.
Explanation:
a) What is the formula of the hydrate?
The mass of the hydrated sample (NiSO₄.xH₂O) = 5.0 g,
The mass of the anhydrous salt (NiSO₄) = 2.755 g,
The mass of water = 5.0 g - 2.755 g = 2.245 g.
∴ no. of moles of water = mass/molar mass = (2.245 g)/(18.0 g/mol) = 0.1247 mol.
∴ no. of moles of anhydrous salt (NiSO₄) = mass/molar mass = (2.755 g)/(154.75 g/mol) = 0.0178 mol.
∴ water of crystallization in the sample (x) = no. of moles of water/no. of moles of anhydrous salt (NiSO₄) = (0.1247 mol)/(0.0178 mol) = 7.0.
b) What is the full chemical name for the hydrate?
The name of the salt (NiSO₄.7H₂O) is Nickel sulfate hepta hydrate.
c) What is the molar mass of the hydrate?
(NiSO₄.7H₂O)
The molar mass = molar mass of NiSO₄ + 7(molar mass of H₂O) = (154.75 g/mol) + 7(18.0 g/mol) = 280.83 g/mol.
d) What is the mass % of water in the hydrate?
The mass % of water = (mass of water)/(mass of hydrated sample) x 100 = (2.245 g)/(5.0 g) x 100 = 44.9%.
What can a drop of liquid mercury be described as?
Answer:
a pure substance and an element
Explanation:
A drop of liquid mercury be described as a pure substance and an element.
Mercury is one of the known elements in the periodic table. The drop of liquid mercury is pure since it has constant and definite composition as well as distinct chemical properties.
A drop of liquid mercury can be described as dense, metallic, and silver. It remains liquid at room temperature due to its low melting point, has high surface tension leading to spherical drops, and is significantly denser than water.
A drop of liquid mercury can be described as a dense, metallic liquid that is silver in color. It is unique among metals because it has a melting point of -38.83 degrees Celsius (-37.89 degrees Fahrenheit), which allows it to be liquid at room temperature. Mercury has a high surface tension, which causes it to form spherical droplets when placed on a surface.
Because mercury does not wet most other materials, it often forms a strong meniscus when in a container, which is the curved surface you see at the top of the liquid. Additionally, mercury has a high density, about 13.6 times that of water, which explains its heavy weight even in small amounts. This high density also means that objects that would normally sink in water might instead float on a surface of mercury.
As a reminder, while mercury is fascinating to study and observe, it is also toxic and can lead to mercury poisoning if handled improperly. Mercury exposure must always be minimized, and any mercury spills should be addressed with appropriate safety protocols.
What part of Dalton’s atomic theory was later proved to be incorrect?
Answer:
D
Explanation:
It was later identified that atoms of the same element can be different. This is mostly seen in elements with different isotopes. An example is carbon-14 and carbon-12 that have different masses due to differences in neutrons numbers in their nuclei.
Atoms are also divisible into subatomic particles. Today, atoms can be smashed apart into neutrons, protons and electrons particles. This also occurs naturally in radioactive decay.
It was later identified that atoms of the same element can be different. This is mostly seen in elements with different isotopes. The correct option is D.
Thus, An example is carbon-14 and carbon-12 that have different masses due to differences in neutrons numbers in their nuclei.
Atoms are also divisible into subatomic particles. Today, atoms can be smashed apart into neutrons, protons and electrons particles. This also occurs naturally in radioactive decay.
John Dalton, an English physicist and chemist, proposed the atomic hypothesis in 1808 as a scientific theory about the composition of matter. It claimed that tiny, indivisible particles called "atoms" make up all substance.
According to Dalton's atomic theory, atoms, which are indestructible and indivisible building blocks, make up all substances. Unlike other elements, which have atoms of different sizes and weights, an element's atoms have all the same size and mass.
Thus, It was later identified that atoms of the same element can be different. This is mostly seen in elements with different isotopes. The correct option is D.
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the steps of the scientific method in order are (3 points) Purpose, Experiment, Hypothesis, Analysis, Conclusion Purpose, Hypothesis, Experiment, Analysis, Conclusion Hypothesis, Experiment, Analysis, Conclusion Purpose, Hypothesis, Experiment, Conclusion
Answer:
second one
Explanation:
Iron pyrite, FeS2, is known as Fool's Gold because it is a shiny yellow solid which is similar in appearance to gold. Iron pyrite is an ionic compound. Gold is a metallic element.
- Iron pyrite, FeS2, contains positive and negative ions. The positive ion is Fe2+.
1) What is the formula of the negative ion?
Answer:
Explanation:
The algebraic sum of all the oxidation numbers of all atoms in a neutral compound is zero.
In order to know the formula of the negative Sulfur ion in pyrite, we must determine its oxidation state.
Let us make the make the oxidation number of sulfur = x
Therefore, FeS₂:
+2 +2x = 0
+2 = -2x
x = -1
The formula of the negative ion is S⁻
Which best describes nuclear fission?
O A nucleus spontaneously splits and absorbs energy,
O Two nuclei spontaneously combine and absorb energy,
O A nucleus collides with a neutron and splits, releasing energy.
Nuclei combine to form a heavier nucleus, releasing energy
Nuclear fission is a nuclear reaction where a nucleus absorbs a neutron and splits into two smaller nuclei, releasing energy and more neutrons, which can cause a chain reaction. It's used in nuclear reactors and nuclear weapons.
Nuclear fission is the process in which a nucleus absorbs a neutron and splits into two lighter nuclei, known as fission fragments, releasing a significant amount of energy. This reaction is exothermic, meaning it releases energy in the form of heat, gamma rays, and the kinetic energy of additional neutrons.
These free neutrons may go on to induce fission in other nuclei, creating a chain reaction. A critical aspect of fission is that a minimum amount of fissile material, known as the critical mass, is necessary for a sustained chain reaction to occur. Therefore, the correct option that describes this process is 'A nucleus collides with a neutron and splits, releasing energy.'
The enormous energy release from fission makes it the foundational principle behind nuclear reactors and nuclear weapons. The fission of heavy elements like uranium or plutonium is harnessed as a heat source in nuclear power plants to produce electricity or to drive explosive reactions in atomic bombs.
Answer:
D : Nuclei combine to form a heavier nucleus, releasing energy.
Explanation:
Nuclear fusion is a process by which two or more atomic nuclei combine to form one or more different atomic nuclei and subatomic particles. The nuclei usually involved are deuterium and tritium, which are hydrogen variants. The difference in mass between the reactants and products is manifested as either the release or absorption of energy. Fusion reactions take place in a state of matter called plasma, which is a hot, charged gas made of positive ions and free-moving electrons. Fusion reactions release massive amounts of energy, and this is the same process that powers the sun
Which element below could be an isotope of beryllium
sodium-10
beryllium-10
boron-9
carbon-9
Answer:
beryllium
Explanation:
isotopes are same elements
Answer:
beryllium-10
Explanation:
First let's remember what an isotope is
Isotopes are atoms of the same element, whose nucleus have a different amount of neutrons, and therefore, differ in mass number .
Since isotopes are atoms of the same element, the only option that corresponds to beryllium is the option beryllium-10
Which of these expressions are correct variations of the Combined Gas Law? P1V1T2 = P2V2T1 both
Answer:
Explanation:
The combined gas law is also known as general gas law and it is the reduction of the ideal gas equation. In the combined gas law, we assume that n= 1
From PV=nRT
[tex]\frac{PV}{T}[/tex] = R (constant) if n= 1
∴ [tex]\frac{P_{1} V_{1} }{T_{1} }[/tex] = [tex]\frac{P_{2} V_{2} }{T_{2} }[/tex] = [tex]\frac{P_{n} V_{n} }{T_{n} }[/tex]
Answer: Both!
Explanation:
Which of these elements is a metal?
Answer:
The options are missing, so I will answer the question in a general manner.
This group of elements includes the alkali metals, alkaline earth metals, transition metals, basic metals, lanthanides and actinides. Depending on conditions, elements belonging to the metalloid group may behave like metals. So, if you want to know if an element is a metal, just found it in the periodic table.
When bonding with nonmetals in ionic compounds, they are converted into cations. When bonding together they make metallic compounds. When multiple metals bound they form alloys (these can include nonmetals too).
Using a value of Ksp = 1.8 x 10-2 for the reaction PbCl2 Pb+2(aq) + 2Cl -(aq). If the value of Ksp was determined to be only 1.2 x 10-2: Too much solid has dissolved. Additional precipitate is forming. The solution is unsaturated. The ions are now combining to reduce their concentrations.
Answer:
The ions are now combining to reduce their concentrations.
Explanation:
For the chemical equation:PbCl₂(s) ⇄ Pb²⁺(aq) + 2Cl⁻(aq),
It is mentioned that the value of Ksp is 1.8 × 10⁻².
∵ The solubility product is lower for this reaction that means the ions produced are getting combined.
∴ Resulting in reducing the concentration of the ions and increasing the formation of the solid lead chloride.
So, The ions are now combining to reduce their concentrations.Answer:
The ions are now combining to reduce their concentrations.
Explanation:
APPLYING SKILLS #1 & #2: Calculating the percentage yield
5.75g of sodium is reacted with chlorine to produce sodium chloride.
If the actual yield is 10.2g, calculate the percentage yield. Leave your
answer to 3 significant figures (4 marks)
2Na + Cl2 → 2Naci
Answer:
69.8 %.
Explanation:
2Na + Cl2 = 2NaCl
Using Relative Atomic Masses:
2*22.99 g sodium should produce 2*(22.99 + 35.45) = 116.88 g of sodium chloride
So 5.75 g Na should give 116.88 * 5.75 / 2*22.99 g = 14.62 g NaCl
% yield = 10.2 / 14.62 = 69.8%.
2Na + Cl2 = 2NaCl
Using Relative Atomic Masses:
2×22.99 g sodium should produce 2×(22.99 + 35.45) = 116.88 g of sodium chloride
So 5.75 g Na should give 116.88 ×5.75 / 2×22.99 g = 14.62 g NaCl
percentage yield = 10.2 / 14.62 = 69.8%.
Sodium chloride is the chemical name for salt. Sodium is an electrolyte that regulates the amount of water in your body. Sodium also plays a part in nerve impulses and muscle contractions.
What is sodium chloride used for?Sodium chloride is an essential nutrient and is used in healthcare to help prevent patients from becoming dehydrated. It is used as a food preservative and as a seasoning to enhance flavor.
Sodium chloride is also used in manufacturing to make plastics and other products. It is also used to de-ice roads and sidewalks.
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The ideal gas constant, R has several different values that could be used. Which quantity causes these differences?
pressure
temperature
volume
moles
Answer: Pressure
Explanation:
The pressure is sometimes measured in different units
Answer:
pressure
Explanation:
The different values of R are as follows:
R = 0.0821 liter•atm/mol•K.
R = 62.3637 L•Torr/mol•K or L•mmHg/mol•K.
Here the different units of pressure are atm, Torr and mmHg.
The unit of volume, temperature and moles are Liter (L), Kelvin (K) and mol respectively.
When different values of Pressure are used and expressed in different units that cause a change in the value of R.
2. Iron reacts with oxygen gas according to the following equation:
4 Fe + 3 O2 -> 2 Fe2O3
If 2 moles of oxygen gas is used in the reaction,
a) how many moles of iron, Fe, will be required?
(b) how many moles of iron(III) oxide, Fe2O3, will be produced?
3. Potassium sulfate can be prepared by the reaction between dilute sulfuric acid
and potassium carbonate.
H2SO4 + K2CO3 → K2SO4 + CO2 + H2O
Calculate the mass of potassium sulfate that can be prepared from 3.45 g of
potassium carbonate.
4. The reaction between zinc and aqueous chromium(III) nitrate can be represented
by the following equation:
3 Zn (s) + 2 Cr(NO3)3 → 3 Zn(NO3)2 + 2 Cr
If 16.25 g of zinc is used to react with chromium(III) nitrate, calculate the mass of
chromium that will be produced.
5. Ethane, CzHe, burns in oxygen gas according to the following equation:
2 C2He + 7 02 – 4 CO2 + 6H20
If 72 dm of ethane gas is completely burnt in oxygen, calculate
(a) the volume of carbon dioxide, measured at room temperature and
pressure produced.
(b) the volume of oxygen, measured at room temperature and pressure
required
Answer:
2. a) 2.67 mol.
b) 1.33 mol.
3. 4.35 g.
4. 8.67 g.
5. a) 143.86 L.
b) 251.75 L.
Explanation:
2. Iron reacts with oxygen gas according to the following equation:
4Fe + 3O₂ → 2Fe₂O₃ , If 2 moles of oxygen gas is used in the reaction,
Fe reacts with O₂ according to the balanced equation:4Fe + 3O₂ → 2Fe₂O₃,
It is clear that 4 mole of Fe react with 3 mole of O₂ to produce 2 moles of Fe₂O₃.
a) how many moles of iron, Fe, will be required?
using cross multiplication:
3 mol of O₂ require → 4 mol of Fe, from the stichiometry.
2 mol of O₂ require → ??? mol of Fe.
∴ The no. of moles of of Fe are required = (2 mol)(4mol)/(3 mol) = 2.67 mol.
(b) how many moles of iron(III) oxide, Fe₂O₃, will be produced?
using cross multiplication:
3 mol of O₂ produce → 2 mol of Fe₂O₃, from the stichiometry.
2 mol of O₂ require → ??? mol of Fe₂O₃.
∴ The no. of moles of of Fe₂O₃ are produced = (2 mol)(2 mol)/(3 mol) = 1.33 mol.
3. Potassium sulfate can be prepared by the reaction between dilute sulfuric acid and potassium carbonate.
H₂SO₄ + K₂CO₃ → K₂SO₄ + CO₂ + H₂O,
Calculate the mass of potassium sulfate that can be prepared from 3.45 g of potassium carbonate.
H₂SO₄ reacts with K₂CO₃ according to the balanced equation:H₂SO₄ + K₂CO₃ → K₂SO₄ + CO₂ + H₂O,
It is clear that 1 mole of H₂SO₄ reacts with 1 mole of K₂CO₃ to produce 1 mole of K₂SO₄, 1 mole of CO₂ and 1 mole of H₂O.
Firstly, we need to calculate the no. of moles of 3.45 g of K₂CO₃:
no. of moles of K₂CO₃ = mass/molar mass = (3.45 g)/(138.205 g/mol) = 0.025 mol.
using cross multiplication:
1 mol of K₂CO₃ produce → 1 mol of K₂SO₄, from the stichiometry.
∴ 0.025 mol of K₂CO₃ produce → 0.025 mol of K₂SO₄.
∴ The mass of K₂SO₄ are produced = (no. of moles of K₂SO₄ produced)(molar mass of K₂SO₄) = (0.025 mol)(174.259 g/mol) = 4.35 g.
4. The reaction between zinc and aqueous chromium(III) nitrate can be represented by the following equation:
3Zn(s) + 2Cr(NO₃)₃ → 3Zn(NO₃)₂ + 2Cr
If 16.25 g of zinc is used to react with chromium(III) nitrate, calculate the mass of chromium that will be produced.
Zn reacts with Cr(NO₃)₃ according to the balanced equation:3Zn(s) + 2Cr(NO₃)₃ → 3Zn(NO₃)₂ + 2Cr ,
It is clear that 3 mole of Zn reacts with 2 mole of Cr(NO₃)₃ to produce 3 mole of Zn(NO₃)₂ and 2 mole of Cr.
Firstly, we need to calculate the no. of moles of 16.25 g of Zn:
no. of moles of Zn = mass/atomic mass = (16.25 g)/(65.38 g/mol) = 0.25 mol.
using cross multiplication:
3 mol of Zn produce → 2 mol of Cr, from the stichiometry.
∴ 0.25 mol of Zn produce → ??? mol of Cr.
∴ The no. of moles of Cr are produced = (2 mol)(0.25 mol)/(3 mol) = 0.167 mol.
∴ The mass of Cr are produced = (no. of moles of Cr produced)(atomic mass of Cr) = (0.167 mol)(51.9961 g/mol) = 8.67 g.
5. Ethane, C₂H₆, burns in oxygen gas according to the following equation:
2 C₂H₆ + 7 O₂ → 4 CO₂ + 6H₂O,
If 72 dm³ of ethane gas is completely burnt in oxygen, calculate
(a) the volume of carbon dioxide, measured at room temperature and
pressure produced.
Firstly, we can calculate the no. of moles of 72 dm³ ethane at room temperature and pressure using the general law of ideal gas: PV = nRT.
where, P is the pressure of the gas in atm (P = 1.0 atm).
V is the volume of the gas in L (V = 72.0 dm³ = 72.0 L).
n is the no. of moles of the gas in mol (n = ??? mol).
R is the general gas constant (R = 0.0821 L.atm/mol.K),
T is the temperature of the gas in K (T = 298.0 K, room temperature).
∴ n of ethane = PV/RT = (1.0 atm)(72.0 L)/(0.0821 L.atm/mol.K)(298.0 K) = 2.94 mol.
So, we can calculate the no. of moles of CO₂:
using cross multiplication:
2 mol of C₂H₆ produce → 4 mol of CO₂, from the stichiometry.
∴ 2.94 mol of C₂H₆ produce → ??? mol of CO₂.
∴ The no. of moles of CO₂ are produced = (2.94 mol)(4.0 mol)/(2 mol) = 5.88 mol.
∴ The volume of moles of CO₂ are produced = nRT/P = (5.88 mol)(0.0821 L.atm/mol.K)(298.0 K)/(1.0 atm) = 143.86 L.
(b) the volume of oxygen, measured at room temperature and pressure
required.
using cross multiplication:
2 mol of C₂H₆ require → 7 mol of O₂, from the stichiometry.
∴ 2.94 mol of C₂H₆ require → ??? mol of O₂.
∴ The no. of moles of O₂ are required = (2.94 mol)(7.0 mol)/(2 mol) = 10.29 mol.
∴ The volume of moles of O₂ are produced = nRT/P = (10.29 mol)(0.0821 L.atm/mol.K)(298.0 K)/(1.0 atm) = 251.75 L.
How many moles of air are there in a 3 L container at 1 atm pressure and 294 K?Use PV=nRT
The ideal gas law states: [tex]PV=nRT[/tex]
If we put in the data.
[tex]
1\cdot7=n\cdot8.31\cdot294 \\
n=\boxed{2.865\cdot10^{-3}mol}=\boxed{2.865mmol}
[/tex]
Hope this helps.
r3t40
Using the ideal gas law PV = nRT, the number of moles of air in a 3 L container at 1 atm and 294 K is calculated to be approximately 0.124 moles.
Calculating Moles of Air Using the Ideal Gas Law
To find the number of moles of air in a 3 L container at 1 atm pressure and 294 K, we can use the ideal gas law, PV = nRT. We are given the following values: P (pressure) = 1 atm, V (volume) = 3 L, T (temperature) = 294 K. We can use R (the ideal gas constant) = 0.08206 L-atm/mol-K, which is appropriate for the units provided.
Step-by-step solution:
Rearrange the ideal gas law formula to solve for n (moles of gas): n = PV / RT.Plug in the known values: n = (1 atm)After doing the math, we find that the number of moles n of air is approximately 0.124 moles.
the concentration of the radio active isotope potassium-40 in a rock sample is found to be 6.25%. what is the age of the rock
Answer:
5.0 x 10⁹ years.
Explanation:
It is known that the decay of a radioactive isotope isotope obeys first order kinetics.Half-life time is the time needed for the reactants to be in its half concentration.If reactant has initial concentration [A₀], after half-life time its concentration will be ([A₀]/2).Also, it is clear that in first order decay the half-life time is independent of the initial concentration.The half-life of K-40 = 1.251 × 10⁹ years.For, first order reactions:k = ln(2)/(t1/2) = 0.693/(t1/2).
Where, k is the rate constant of the reaction.
t1/2 is the half-life of the reaction.
∴ k =0.693/(t1/2) = 0.693/(1.251 × 10⁹ years) = 5.54 x 10⁻¹⁰ year⁻¹.
Also, we have the integral law of first order reaction:kt = ln([A₀]/[A]),
where, k is the rate constant of the reaction (k = 5.54 x 10⁻¹⁰ year⁻¹).
t is the time of the reaction (t = ??? year).
[A₀] is the initial concentration of (K-40) ([A₀] = 100%).
[A] is the remaining concentration of (K-40) ([A] = 6.25%).
∴ (5.54 x 10⁻¹⁰ year⁻¹)(t) = ln((100%)/( 6.25%))
∴ (5.54 x 10⁻¹⁰ year⁻¹)(t) = 2.77.
∴ t = 2.77/(5.54 x 10⁻¹⁰ year⁻¹) = 5.0 x 10⁹ years.
Answer:
[tex]\boxed{4.99 \times10^{9} \text{ y}}[/tex]
Explanation:
The half-life of potassium-40 (1.248 ×10⁹ y) is the time it takes for half of it to decay.
After one half-life, half (50 %) of the original amount will remain.
After a second half-life, half of that amount (25 %) will remain, and so on.
We can construct a table as follows:
[tex]\begin{array}{cccc}\textbf{No. of} & &\textbf{Fraction} &\textbf{Percent}\\ \textbf{Half-lives} & \textbf{t/(10$^{9}$ y}) &\textbf{Remaining} &\textbf{Remaining}\\0 & 0 & 1 & 100\\\\1 & 1.248 & \dfrac{1}{2} & 50\\\\2 & 2.496 & \dfrac{1}{4} & 25\\\\3 & 3.744 & \dfrac{1}{8} & 12.5\\\\4 & 4.992 & \dfrac{1}{16} & 6.25\\\\5 & 6.240 & \dfrac{1}{32} & 3.125\\\\\end{array}[/tex]
We see that after four half-lives, ¹/₁₆ or 6.25 % of the original mass remains.
Conversely, if 6.25 % of the sample remains, the age of the sample must be four half-lives.
[tex]\text{Age of rock} = 4 \times 1.248 \times 10^{9}\text{ y}= \boxed{\mathbf{4.99 \times 10^{9}} \textbf{ y}}[/tex]
. Write the following isotope in nuclide notation (e.g., “ ”): copper-70
Answer:
[tex]{\boxed{\text{$_{29}^{70}${Cu}}}[/tex]
Explanation:
The atomic number (Z) of copper is 29 and this isotope has an atomic mass (A) of 70.
The general symbol for an isotope E is [tex]_{Z}^{A}\text{E}[/tex].
The atomic number is a left subscript, and the atomic mass is a left superscript.
[tex]\rm {\text{The nuclide notation for copper-70 is }}{\boxed{\textbf{$_{29}^{70}${Cu}}}[/tex]
Answer:
What is the density of an object that has a mass of 10 g and a volume
of 5 mL?
a. 0.5 g/ mL
b. 2 g/mL
c. 15 g/ mL
d. 50 g/ mL
Answer:
b. 2 g/mL
Explanation:
Density=mass/volume.
so: D=10g/5mL
Density=2g/mL
Answer:
The correct answer is option b.
Explanation:
To calculate density of a substance, we use the equation:
[tex]\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}[/tex]
We are given:
Mass of an object = 10 g
Volume of an object = 5 mL
Density of an object = d
Putting values in above equation, we get:
[tex]d=\frac{10 g}{5 mL}=2 g/mL[/tex]
2 g/mL is the density of an object that has a mass of 10 g and a volume of 5 mL.
A sample of neon has a volume of 5.00 L, and initial temperature of 425 K, and an initial pressure of 1.23 atm. If the final temperature is 288 K, and the final volume is 0.555 L, what is the final pressure?
5.04 atm
7.51 atm
1.82 atm
9.08 atm
Answer:
7.51
Explanation:
general gas law
the product of pressure and volume is divided by absolute temperature
0.0045 cm or 0.0045 in. Larger quantity
Hello There!
0.0045 Inches are larger than centimeters.
When does carbon dioxide absorb the most heat energy
Answer:Carbon dioxide absorbs the most heat energy during SUBLIMATION. By definition, sublimation is the transition of a substance from the solid to the gas phase without passing through the intermediate liquid phase. Hope this answers your question.
Explanation:
Answer:
sublimation
Explanation: