Body systems associated with gases(particularly that which was asked):
• Respiratory System.
• Cardiovascular System or Circulatory System or Vascular System.
Note: All these three are the names of the same thing i.e cardiovascular system, circulatory system and vascular system.
What products are formed in the electrolysis of 1.0 M
aqueous HBr?
In the electrolysis of 1.0 M aqueous HBr, hydrogen gas is formed at the cathode, while bromine gas and hydroxide ions are formed at the anode.
Explanation:In the electrolysis of 1.0 M aqueous HBr, the following products are formed: hydrogen gas (H2) at the cathode, and bromine gas (Br2) and hydroxide ions (OH-) at the anode.
At the cathode, reduction occurs where two hydrogen ions (H+) gain electrons to form hydrogen gas:
2H+ + 2e- -> H2
At the anode, oxidation occurs where bromide ions (Br-) lose electrons to form bromine gas and hydroxide ions:
2Br- - 2e- -> Br2
2H2O - 4e- -> 4OH- + O2
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25) If an object’s density is greater than 1.00 g/mL, it will ______________ in water.
A) Sink
B) Float
__________________________________________
If an object’s density is less than 1.00 g/mL, it will ______________ in water.
A) Sink
B) Float
_______________________________________________________
26) What is the density of a rock if it has a mass of 50 g and a volume of 10 mL? (You must show your work!)
Answer:
1- Option A = Sink
2- Option B = Float
Explanation:
1- If an object’s density is greater than 1.00 g/mL, it will sink in water.
For example, the density of aluminum is 2.7g/cm³. That is why it will sink in water.
2- If an object’s density is less than 1.00 g/mL, it will float in water.
For example, the density of oak is 0.7 g/cm³. That is why oak will float in water.
3- Given data:
Mass, m = 50 g
Volume, v = 10 cm3 ( 1ml = 1cm3)
Formula of density :
Density = mass/ volume
d = m/v
d = 50g/10cm3
d = 5 g/cm3
Arrange the levels of ecological organization from smallest to largest. (ecosystem, population, community, organism)
Answer:
organism, population, community, ecosystem
Explanation:
Answer: Organism, Population, Community, and lastly Ecosystem
Explanation: Organism is one living thing. Population is a group of organisms of one type that live together. Communities are populations that live together in an area. Ecosystem is a community with its non living surroundings.
Hope this helps :)
What will the final volume of a gas be if it is heated from 9 K to 117 K, and the initial volume is 85.5 L?
Answer:
1111.5L
Explanation:
A weather balloon contains 1.10X10 to the power of 5 mol of helium and has a volume of 2.70x10 to the power of 6 L at 1.00 atm pressure. Calculate the temperature of the helium
Answer:
299.14 K or 26°C
Explanation:
The ideal gas law, also called the general gas equation, is the equation of state of a hypothetical ideal gas.
The ideal gas law is often written as
PV = nRT
where P ,V and T are the pressure, volume and absolute temperature;
n is the number of moles of gas and R is the ideal gas constant.
n=1.10 x 10^5 mol
V= 2.70 x 10^6 L
P= 1.00 atm= 101.325 kPa
R= 8.314 kPa*L/ mol*K
when the formula is rearranged, T=PV/ nR
T = (101.325kPa * 2.70 x 10^6 L)/ (1.10 x 10^5 mol * 8.314 kPa*L/ mol*K)
T = 299.1421917 K
or
T = 299.14 - 273.15 = 25.99 = 26°C
Using the Ideal Gas law, we find the temperature T = ((1.00 atm)*(2.70x10^6 L))/((1.10x10^5 mol)*(0.0821 L.atm/K.mol)). Calculating that gives you the temperature (in Kelvin) of the helium in the balloon.
Explanation:In that case, you're being asked to find the temperature of helium inside a weather balloon. The Ideal Gas Law (PV=nRT) will be useful here, where P is the pressure (1 atm), V is the volume (2.7x10 to the power of 6 L), n is the number of moles of helium (1.10x10 to the given power of 5 mol), R is the gas constant (0.0821 L.atm/K.mol) and T is the temperature which we need to calculate.
So, the Ideal Gas Law becomes: (1.00 atm)*(2.70x10^6 L) = (1.10x10^5 mol)*(0.0821 L.atm/K.mol)*T
Solving for T by isolating it on one side gives T = ((1.00 atm)*(2.70x10^6 L))/((1.10x10^5 mol)*(0.0821 L.atm/K.mol))
Calculating that should give you the temperature (in Kelvin) of the helium in the balloon.
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what are the main risk and main benefit when a society uses energy from nuclear fission?
a. risk of harm to flying animals; benefit of reducing greenhouse gases
b. risk of high greenhouse gas and particle emissions; benefit of reducing short-term costs
c. risk of groundwater contamination; benefit of using a renewable resource
d. risk from radioactive material; benefit of obtaining low-cost energy
Answer:
D.
Explanation:
Nuclear energy does not have greenhouse gas emissions. The emissions produced by nuclear fission plants are similar to renewable energy sources.The generation of power using nuclear energy does not affect air quality thus providing a clean source of energy.Nuclear energy originates from radioactive material which are harmful to living organisms.
Answer:
D. risk from radioactive material; benefit of obtaining low-cost energy
Explanation:
I just took the test. Ap*x
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HELP
Strong conductivity of plasma allows it to act and react as ______________ and ____________ fields
Answer:
I think it is high and electric
Explanation:
Answer:
strong conductivity of plasma allows it to act and react as electric and magnetic fields.
calculate the empirical formula 9.1 g of lithium and 10.4 g of oxygen
To find the empirical formula of a compound with 9.1 g of lithium and 10.4 g of oxygen, we calculate the moles of each element and express their ratio in the simplest whole numbers. The empirical formula is determined to be Li₂O.
Explanation:To calculate the empirical formula of a compound formed from lithium and oxygen, we need to determine the moles of each element present in the 9.1 grams of lithium and 10.4 grams of oxygen. The molar mass of lithium (Li) is approximately 6.94 g/mol, and the molar mass of oxygen (O) is about 16.00 g/mol.
First, we calculate the moles of lithium:
Moles of Li = mass (g) ÷ molar mass (g/mol) = 9.1 g ÷ 6.94 g/mol = 1.31 moles of Li
Next, we calculate the moles of oxygen:
Moles of O = mass (g) ÷ molar mass (g/mol) = 10.4 g ÷ 16.00 g/mol = 0.65 moles of O
Now we determine the simplest whole number ratio of the elements in the compound:
Li to O ratio = 1.31 moles of Li ÷ 0.65 moles of O = 2:1
Therefore, the empirical formula is Li₂O
which of the following is not a base?
A. bleach
B.toothpaste
C.shampoo
D.orange
Answer:
c. shampoo
Explanation:
What is true about the relative concentrations of hydrogen ions or hydroxide ions in an acidic solution?
a
Hydrogen-concentration is less
b
Hydroxide-ion concentration is greater
c
The concentrations are equal
d
Hydroxide-ion concentration is less
Hydroxide ion concentration is less this statement is true about the relative concentration of hydrogen ions or hydroxide ions in an acidic solution.
Hence, Option (D) is correct answer.
What is pH ?pH is used to measure whether the substance is acidic, basic or neutral and the range is 0 - 14. If the pH is less than 7 then the solution is acidic in nature. If the pH is more than 7 then the solution is basic in nature. If the pH is equal to 7 then the solution is neutral in nature.
What is concentration of hydrogen ion or hydroxide ion in acidic solution ?Acidic solution means the pH of the solution is less than 7. When the solution has pH less than 7 it shows that the hydrogen ion concentration is higher than the hydroxide ion concentration.
Thus, from the above conclusion we can say that Hydroxide ion concentration is less this statement is true about the relative concentration of hydrogen ions or hydroxide ions in an acidic solution.
Hence, Option (D) is correct answer.
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In an acidic solution, the concentration of hydrogen or hydronium ions is greater, and as a result, the concentration of hydroxide ions is less.
Explanation:In an acidic solution, the concentration of hydrogen ions (H+) or hydronium ions (H3O+) is greater than the concentration of hydroxide ions (OH-). This is due to the ionization of the acid in water, which adds more hydrogen ions into the solution, leading to a proportionally lower concentration of hydroxide ions. As per Le Châtelier's principle, the reaction equilibrium of water autoionization shifts to the left, which reduces the concentration of hydroxide ions. Therefore, the correct answer is d: Hydroxide-ion concentration is less.
When 2 grams of powdered lead (IV) oxide was added to 100 cm3 of hydrogen peroxide, water and oxygen were produced. Lead (IV) oxide was not used up in the reaction. Based on the information, which of the following is likely to decrease the rate of formation of the products?
Replacing the powdered lead oxide with its large crystals
Removing lead (IV) oxide from the reaction mixture
Using 50 cm3 of hydrogen peroxide
Using 1.0 gram of lead (IV) oxide
Answer:
The right answer is:
Replacing the powdered lead oxide with its large crystals
Removing lead (IV) oxide from the reaction mixture
Using 1.0 gram of lead (IV) oxide
Explanation:
Based on the given information this reaction is the catalytic decomposition of H₂O₂ into water and oxygen using Lead (IV) oxide as a catalyst.
The catalyst surface area is directly proportional to the reaction rate So, Replacing the powdered lead oxide with its large crystals would decrease the reaction rate due to the has larger surface area than its large crystals.2. Also, Removing lead (IV) oxide from the reaction mixture the reaction rate decreased because as the catalyst is removed.
3. Using 50 cm³ of hydrogen peroxide doesn't affect the rate because the concentration of the reactant doesn't change.
4. Using 1.0 gram of lead (IV) oxide would decrease the reaction rate because the amount of catalyst decreased
So, The right answer is:
Replacing the powdered lead oxide with its large crystals
Removing lead (IV) oxide from the reaction mixture
Using 1.0 gram of lead (IV) oxide
-Material A has a melting point of 34°C whereas Material B has a melting point of 56°C. Both materials have been placed in an oven at 50°C Describe the state of each material after being being in the oven for a period of time.
I'm confused, if material B is on for the same amount of time does that mean that it has liquified and material A has melted slightly?
Answer:
Explanation:
Material A has a melting point of 34°C
Material B has a melting point of 56°C
Both materials, lets say a metal have been subjected to a temperature of 50°C
After a period of time, both of them would have melted to their liquid state.
The atoms of the solids would vibrates and the bonds would begin to break to form melt.
Material A would be the first to melt as it has a lower melting point. The lower the melting point, the faster and quicker it would reach its melting temperature.
Material B would need to accumulate more heat and its temperature would continue to rise for the phase change to occur. As it reaches the 50°C mark, the bonds are set free and a melt forms.
What is the rate law for the reaction?
Answer:
The correct answer option A.
Explanation:
The reaction rate is determined experimentally for different concentrations of the reactants. These data indicate that by changing the concentration of Nh4 + or NO2-, the reaction rate changes. If the concentration of Nh4 + is doubled, keeping constant at NO2- the reaction rate is doubled, and if the concentration of that same reactant is changed by a factor of 4, it is quadrupled, and so on. If the concentration of NO2- is now modified in the same way as the previous one, it is observed that it also changes the reaction rate in this way. And he overall dependence of the reaction on the concentration will be the same for both reactants.
Therefore the reaction rate is proportional to the concentration of Nh4 + and NO2-.
Snow forms when clouds cool to the dew point. True False
Answer:
False.
Explanation:
Snow forms when tiny ice crystals in clouds stick together to make snowflakes.
Answer:
what he said lol.
Explanation:
What is the number of moles in 500 L of He gas at STP
Answer:
22.3 mol
Explanation:
He is in STP conditions
This means that it is in standard conditions of temperature and pressure, under these conditions the pressure has a value of 1 atm and the temperature has a value of 273 K
To calculate the number of moles in 500L of He gas we use the ideal gas equation
[tex]P.V=n.r.T\\r(constant of ideal gases)= 0.082\frac{atm.L}{K.mol}[/tex]
We cleared the moles (n)
[tex]P.V=nr.T\\\frac{P.V}{r.T}=n\\\frac{1atm.500L}{0.082atm.L/K.mol.273K}=n\\\\22.3 mol=n[/tex]
The number of moles in 500 L of He gas at STP 22.3 mol
The number of moles in 500 L of helium (He) gas at standard temperature and pressure (STP) is approximately 22.32, based on the standard molar volume concept of chemistry.
Explanation:The number of moles in 500 L of He gas at STP can be determined using the standard molar volume, which states that at standard temperature and pressure (STP), one mole of any ideal gas occupies a volume of 22.4 L. In this case, to find the moles of helium gas, you would use the formula n = V/V_m, where n is the number of moles, V is the volume of the gas, and V_m is the molar volume at STP.
Substituting the given values into the equation: n = 500 L/22.4 L/mol = 22.32 moles.So, there are approximately 22.32 moles of helium gas in 500 L at STP.
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If the amount of CFCs in the atmosphere decreases, then __.
Plato users: ozone holes could begin to shrink in size
Answer:
Ozone holes could begin to shrink in size.
Explanation:
The use of CFCs today is one of the anthropogenic causes of ozone depletion. CFCs are found in Air conditioners, refrigerators and are excellent coolants.
When CFCs are released into the atmosphere, they react spontaneously with ozone.
Ozone is made up of 3 oxygen atoms and it serves as a protective covering for the very harmful ultraviolet rays from reaching the earth. Ozone cuts off these radiation and it reflects them back into space.
Chloroflurocarbons release Chlroine atoms when they get broken down by ultraviolet rays. The Cl released produces a series of reactions in the presence of ozone.
Chlorine is very reactive as it is an halogen. It requires just an electron to complete its octet.
Chlorine freely reacts with the ozone producing a range of compounds. Most of the ozone becomes oxygen molecules.
This would deplete the ozone greatly. The increasing use of CFCs leaves holes in the ozone layer. The holes allow for harmful UV rays to reach the earth surface. This can lead to various harm on human lives on the earth surface.
This is why CFCs are not permitted in appliances again.
Gases are easily compressible, but other states of matter are not. Which statement best helps to explain the statement above? Their particles are more lightweight than the particles of the other states. Their particles are more spread out than the particles of the other states. Their particles are more flexible than the particles of the other states. Their particles are smaller in size than the particles of the other states.
Answer:their particles are more spread out than others
Explanation:
Answer:
Number 2
Explanation:
Their particles are more spread out than the particles of the other states
which two traits best help a cactus conserve water in the dry conditions of a west texas desert ecosystem?
The answer is sharp spines and waxy stems. Hope this helped.
(Show your work please)
Answer:
[tex]\boxed{\text{bp =100.106 }^{\circ}\text{C; fp = -0.387 }^{\circ}\text{C; bp =101.68 }^{\circ}\text{C}}[/tex]
Explanation:
Q8. Boiling point
Data:
m(KOH) = 53.1 g
m(H₂O) = 9.10 kg
K_b = 0.512 °C·kg·mol⁻¹
Calculations:
(a) Moles of KOH
[tex]\text{Moles of KOH} = \text{53.1 g KOH} \times \dfrac{\text{1 mol KOH}}{\text{56.11 g KOH}} = \text{0.9464 mol KOH}[/tex]
(b) Molal concentration
The formula for molal concentration (b) is
[tex]b = \dfrac{\text{moles of solute}}{\text{kilograms of solvent}} = \dfrac{0.9464}{9.1} = \text{0.104 mol/kg}[/tex]
(c) Boiling point elevation
The formula for the boiling point elevation ΔTb is
[tex]\Delta T_{b} = iK_{b}b[/tex]
i is the van’t Hoff factor: the number of moles of particles you get from a solute.
For KOH,
KOH(s) ⟶ K⁺(aq) + OH⁻(aq)
1 mol KOH ⟶ 2 mol particles i = 1
[tex]\Delta T_{b} = 2 \times 0.512 \times 0.104 = \text{0.106 }^{\circ}\text{C}[/tex]
(d) Boiling point
[tex]T_{b} = T_{b}^{\circ} + \Delta T_{b} = 100.000 + 0.106 = \text{100.106 }^{\circ}\text{C}[/tex]
Q9. Freezing point
[tex]\Delta T_{f} = iK_{f}b = 2 \times 1.86 \times 0.104 = \text{0.387 }^{\circ}\text{C}\\\\T_{f} = T_{f}^{\circ} - \Delta T_{f} = 0.000 - 0.387 = \text{-0.387 }^{\circ}\text{C}[/tex]
Q10. Boiling point
[tex]\text{Kilograms of phenol} = 645 \times \dfrac{1}{1000} = \text{0.645 kg phenol}\\\\b = \dfrac{0.910}{0.645} = \text{1.411 mol/kg}\\\\\Delta T_{b} = 1\times 1.19 \times 1.411 = \text{1.68 }^{\circ}\text{C}\\T_{b} = 100.00 + 1.68 = \text{101.68 }^{\circ}\text{C}[/tex]
A gas occupies 318 liters at 10.0 atm. What is the pressure if the volume becomes 662.5 L?
Answer:
4.8 atm.
Explanation:
We can use the general law of ideal gas: PV = nRT.where, P is the pressure of the gas in atm.
V is the volume of the gas in L.
n is the no. of moles of the gas in mol.
R is the general gas constant,
T is the temperature of the gas in K.
If n and T are constant, and have two different values of V and P:
P₁V₁ = P₂V₂
P₁ = 10.0 atm, V₁ = 318.0 L.
P₂ = ??? atm, V₂ = 662.5 L.
∴ P₂ = P₁V₁/V₂ = (10.0 atm)(318.0 L)/(662.5 L) = 4.8 atm.
Which property describes how much energy must be added to an atom to remove an outermost election
Answer:
By definition, the first ionization energy of an element is the energy needed to remove the outermost, or highest energy, electron from a neutral atom in the gas phase. The process by which the first ionization energy of hydrogen is measured would be represented by the following equation.
Explanation:
34. Given the fact that the concentrations of reactants and
products are not changing, why is the word dynamic
used to describe chemical equilibrium?
Answer:
The word dynamic is used to describe chemical equilibrium because even though the concentration of reactants and products remains constant, the reaction does not stop, but still continues with the rate of forward reaction equal to the rate of backward reaction. This is opposed to static equilibrium where there is no reaction at all.
Hope this helps you out!
The word dynamic is used to describe chemical equilibrium because, despite concentrations of reactants and products being constant, reactions continue in both directions at the same rate, indicating continuous exchange.
Given the fact that the concentrations of reactants and products are not changing, the word dynamic is used to describe chemical equilibrium because, at this state, the forward and reverse reactions are happening at the same rate. Even though there is no net change in the concentrations of reactants and products, reactions continue to occur in both directions. This means that molecules of reactants are constantly being converted into products at the same rate as products are being converted back into reactants, maintaining a constant concentration of both. Therefore, the equilibrium is dynamic because the reactants and products are in a state of continuous, but balanced, exchange.
Look at the graph below. Will mark brainliest
A graph is shown with Absolute Brightness shown on y axis and Surface temperature in degree Celsius shown on x axis. The Dwarf stars are shown along a slanting line from coordinates 30,000 and minus 3 to 10,000 and minus 4. The Main Sequence stars are shown along a slanting line from coordinates 20,000 and minus 2 to 2,000 and minus 6. The giants are shown along a line parallel to the x axis from coordinates 5,000 and 2 to 2,000 and 3. The supergiants are shown along a line parallel to the x axis from coordinates 7,500 and 4 to 2,500 and 4. Point A has coordinates 20,000 and minus 4. Point B has coordinates 2,500 and minus 4. Point C has coordinates 5,000 and 2. Point D has coordinates 7,000 and 4.
Which of the following stars is most likely to be blue?
Star A
Star B
Star C
Star D
Answer:
Star A
Explanation:
Based on the information provided, we can determine that the color of a star is related to its surface temperature, with hotter stars appearing more blue and cooler stars appearing more red.
Looking at the graph, we can see that the stars along the left side of the graph (with negative values on the x-axis) are hotter than the stars on the right side of the graph. Therefore, Star A, which has coordinates of 20,000 and -4, is hotter than Star B, which has coordinates of 2,500 and -4.
Comparing the coordinates of Star A to the lines representing the different types of stars, we can see that it falls on the line for main sequence stars. Main sequence stars are typically white or blue-white in color, so Star A is most likely to be blue.
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Star D is most likely to be blue, as it has a high surface temperature compared to the other stars listed (7,000 degrees Celsius) and aligns with the typical characteristics of blue stars.
The color of a star is closely related to its surface temperature. Hotter stars tend to appear bluer, while cooler stars appear redder.
Looking at the provided coordinates for the stars:
- Star A has coordinates (20,000, -4), indicating a high surface temperature.
- Star B has coordinates (2,500, -4), indicating a lower surface temperature.
- Star C has coordinates (5,000, 2), indicating a moderate surface temperature.
- Star D has coordinates (7,000, 4), indicating a relatively high surface temperature.
Among the given stars, Star A and Star D have the highest surface temperatures, making them more likely to appear blue. However, between these two, Star D has an even higher temperature, making it the most likely to be blue. Therefore, Star D is the star most likely to be blue.
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If 10.0 L of oxygen gas at STP are heated to 512 Celsius what will be the new volume of the gas if the pressure is also increased to 1.75 ATM?
Answer:
16.4 L
Explanation:
we can use the combined gas law equation that gives the relationship among volume, temperature and pressure conditions of gases.
P1V1/T1 = P2V2/T2
STP conditions are standard temperature and pressure conditions
P1 is standard pressure = 1 atm , T1 is standard temperature = 273 K
and V1 is the volume
P2 is pressure, T2 is temperature and V2 is volume at the second instance
temperature is in kelvin scale,
512 ° + 273 = 785 K
substituting the values in the equation
1 atm x 10.0 L / 273 K = 1.75 atm x V / 785 K
V = 16.4 L
new volume is 16.4 L
What is the mass of 2.30 ×1022 molecules of NaOH (Molar mass = 40.0 g/mol)?
Answer:
1.52 g NaOH
Explanation:
The molar mass M is a physical property defined as the mass of a given substance (chemical element or chemical compound) divided by the amount of substance.
Molar mass of NaOH is 40.0 g/mol
40.0 g/mol contains 6.022 × 10²³ molecules
∴ 2.30 × 10²² molecules will contain (2.30 × 10²²) * (40.0)/6.022× 10²³
= 1.52 g NaOH
if a gas occupies at 5.40 L at a pressure of 1.25atm, what will be its volume at a pressure of 3.00 atm? (Show work)
Answer:
Explanation:
Givens
P = 1.25 atm
V = 5.4 L
P1 = 3 atm
V1 = ??
Formula
The basic formula is P*V = P1 * V1
Solution
1.25 * 5.4 = 3 * V1
6.75 = 3*V1
6.75 /3 = 3*V1/3
2.25 = V1
Need help !!!!! ASAP
The answer is:
The new temperature will be equal to 4 K.
[tex]T_{2}=4K[/tex]
Why?We are given the volume, the first temperature and the new volume after the gas is compressed. To calculate the new temperature after the gas was compressed, we need to use Charles's Law.
Charles's Law establishes a relationship between the volume and the temperature at a gas while its pressure is constant.
Now, to calculate the new temperature we need to assume that the pressure is kept constant, otherwise, the problem would not have a solution.
From Charle's Law, we have:
[tex]\frac{V_{1}}{T_{1}}=\frac{V_{2}}{T_{2}}[/tex]
So, we are given the following information:
[tex]V_{1}=500mL\\T_{1}=20K\\V_{2}=100mL[/tex]
Then, isolating the new temperature and substituting the given information, we have:
[tex]\frac{V_{1}}{T_{1}}=\frac{V_{2}}{T_{2}}[/tex]
[tex]T_{2}=\frac{T_{1}}{V_{1}}*V_{2} \\[/tex]
[tex]T_{2}=\frac{20.00K}{500mL}*100mL\\[/tex]
[tex]T_{2}=4K[/tex]
Hence, the new temperature will be equal to 4 K.
[tex]T_{2}=4K[/tex]
Have a nice day!
Excess magnesium reacts with 165.0 grams of hydrochloric acid in a single displacement reaction.
What volume of hydrogen gas is produced at STP?
Answer:
The volume of hydrogen gas produced will be approximately 50.7 liters under STP.
Explanation:
Relative atomic mass data from a modern periodic table:
H: 1.008;Cl: 35.45.Magnesium is a reactive metal. It reacts with hydrochloric acid to produce
Hydrogen gas [tex]\rm H_2[/tex], andMagnesium chloride, which is a salt.The chemical equation will be something like
[tex]\rm ?\;Mg\;(s) + ?\;HCl \;(aq)\to ?\;H_2 \;(g)+ [\text{Formula of the Salt}][/tex],
where the coefficients and the formula of the salt are to be found.
To determine the number of moles of [tex]\rm H_2[/tex] that will be produced, first find the formula of the salt, magnesium chloride.
Magnesium is a group 2 metal. The oxidation state of magnesium in compounds tends to be +2.
On the other hand, the charge on each chloride ion is -1. Each magnesium ion needs to pair up with two chloride ions for the charge to balance in the salt, magnesium chloride. The formula for the salt will be [tex]\rm MgCl_2[/tex].
[tex]\rm ?\;Mg\;(s) + ?\;HCl\;(aq) \to ?\;H_2 \;(g)+ ?\;MgCl_2\;(aq)[/tex].
Balance the equation. [tex]\rm MgCl_2[/tex] contains the largest number of atoms among all species in this reaction. Start by setting its coefficient to 1.
[tex]\rm ?\;Mg\;(s) + ?\;HCl\;(aq) \to ?\;H_2 \;(g)+ {\bf 1\;MgCl_2}\;(aq)[/tex].
The number of [tex]\rm Mg[/tex] and [tex]\rm Cl[/tex] atoms shall be the same on both sides. Therefore
[tex]\rm {\bf 1\;Mg}\;(s) + {\bf 2\;HCl}\;(aq) \to ?\;H_2 \;(g)+ {1\;\underset{\wedge}{Mg}\underset{\wedge}{Cl_2}}\;(aq)[/tex].
The number of [tex]\rm H[/tex] atoms shall also conserve. Hence the equation:
[tex]\rm {1\;Mg}\;(s) + {2\;\underset{\wedge}{H}Cl}\;(aq) \to {\bf 1\;H_2 \;(g)}+ {1\;MgCl_2}\;(aq)[/tex].
How many moles of HCl are available?
[tex]M(\rm HCl) = 1.008 + 35.45 = 36.458\;g\cdot mol^{-1}[/tex].
[tex]\displaystyle n({\rm HCl}) = \frac{m(\text{HCl})}{M(\text{HCl})} = \rm \frac{165.0\;g}{36.458\;g\cdot mol^{-1}} = 4.52576\;mol[/tex].
How many moles of Hydrogen gas will be produced?
Refer to the balanced chemical equation, the coefficient in front of [tex]\rm HCl[/tex] is 2 while the coefficient in front of [tex]\rm H_2[/tex] is 1. In other words, it will take two moles of [tex]\rm HCl[/tex] to produce one mole of [tex]\rm H_2[/tex]. [tex]\rm 4.52576\;mol[/tex] of [tex]\rm HCl[/tex] will produce only one half as much [tex]\rm H_2[/tex].
Alternatively, consider the ratio between the coefficient in front of [tex]\rm H_2[/tex] and [tex]\rm HCl[/tex] is:
[tex]\displaystyle \frac{n(\text{H}_2)}{n(\text{HCl})} = \frac{1}{2}[/tex].
[tex]\displaystyle n(\text{H}_2) = n(\text{HCl})\cdot \frac{n(\text{H}_2)}{n(\text{HCl})} = \frac{1}{2}\;n(\text{HCl}) = \rm \frac{1}{2}\times 4.52576\;mol = 2.26288\;mol[/tex].
What will be the volume of that many hydrogen gas?
One mole of an ideal gas occupies a volume of 22.4 liters under STP (where the pressure is 1 atm.) On certain textbook where STP is defined as [tex]\rm 1.00\times 10^{5}\;Pa[/tex], that volume will be 22.7 liters.
[tex]V(\text{H}_2) = \rm 2.26288\;mol\times 22.4\;L\cdot mol^{-1} = 50.69\; L[/tex], or
[tex]V(\text{H}_2) = \rm 2.26288\;mol\times 22.7\;L\cdot mol^{-1} = 51.37\; L[/tex].
The value "165.0 grams" from the question comes with four significant figures. Keep more significant figures than that in calculations. Round the final result to four significant figures.
The temperatures of the two glasses of water shown in the photograph above are 30°C and 0°C. Which of the following is a correct statement about two glasses of water?
A. The cold water has a higher average kinetic energy
B. The warmer water has lower thermal energy
C. The molecules of the cold water move faster
D. The molecules of the warm water have more kinetic images
How to remember the first 20 elements of the periodic table?
The way the brain works is that you learn from repetition, the more you do something the better you get at it. So the more you review the first 20 elements on the periodic table, the more often you'll be able to remember it until you're about to recount them without hardly thinking of it.
My advice to you is to grab some pieces of paper. Cut them up into sixths until you have twenty of them, then write down on each smaller piece of paper the numbers 1 up to 20. Then on the other side of the paper, write down the element. Do this in accordance to their position on the periodic table. Then spend some time guessing as to what element is on the other side of the numbered paper. You'll start guessing, "the first element is Hydrogen. The second element is Helium." And so on. Rinse and repeat until you're able to guess the element depending on its placement on the periodic table. Good luck!
Happy. – H Hydrogen
Henry – He Helium
Lives – Li Lithium
Beside – Be Beryllium
Born – B Boron
Cottage – C Carbon
Near – N Nitrogen
Our – O Oxygen
Friend – F Fluorine.
Nelly – Ne Neon
Nancy – Na Sodium
Mg – Mg Magnesium
Allen – Al Aluminum
Silly – Si Silicon
Patrick – P Phosphorus
Stays – S Sulphur
Close – Cl Chlorine
Arthur – Ar Argon
Kisses – K Potassium
Carrie – Ca Calcium
Hope this helps :)