Answer:
Q= Magnesium R= Chlorine
Explanation:
The element Q should be magnesium and R is chlorine.
An ionic compound is a compound that is formed by the combination of a metal and non-metal. Such bonds forms when there is a transfer of electrons from the metals to the non-metals. This leaves a net positive charge on the metal and a negative charge on the non-metal.
The electrostatic attraction leads to the formation of the bond.
To solve this problem, the hypothetical compound is QR₂
Mg Cl
2 8 2 2 8 7
So, Mg transfers 2 electrons to two atoms of chlorine.
This leads to the formation of the compound MgCl₂
Write a description of how you know a chemical reaction is occurring.
ANSWER FAST FIRST PERSON GETS BRAINLIEST
Answer:
See explanation
Explanation:
Chemical reactions are also referred to as chemical change. A chemical change often leads to the formation of new substances and is not easily reversible.
A chemical reaction may be accompanied by the emission of heat and light, formation of a precipitate, evolution of gas, or a color change.
These observable physical effects may tell us weather a chemical reaction has taken place or not so we have to observe the system closely for any of these effects stated above.
What is the difference between the grassland and savanna biomes?
A)Grassland biomes are closer to the equator and receive more rain.
B)Savanna biomes are closer to the equator and receive more rain.
C)Grassland biomes contain mostly grasses.
D)Savanna biomes contain mostly grasses.
Answer:
C)Grassland biomes contain mostly grasses.
Explanation:
The main differences between a savanna biome and a grassland is that grasslands biomes contain mostly grasses.
Savanna are made up of both grasses and shrubs.
Savanna are a mix of grasslands with some scattered trees in the area. Grasslands are open grass fields. They do not contain much trees as such. The savanna and grasslands are renowned for their fauna diversity of beasts.I need help ASAP please giving brainliest!!
Answer:
Silver Lake Picnic Area, Or C
Explanation:
Drag the tiles to the correct boxes to complete the pairs.
Match the descriptions with the types of blas.
selection bias
expectation bias
confirmation bias
contextual bias
paying more attention to evidence that
confirms one's hypothesis and ignoring
evidence that may discount it
to be swayed from one's conclusion by
additional information
coming to a conclusion before all the
evidence has been processed and therefore
unconsciously disregarding evidence to the
contrary
Answer:
Explanation:
here's the answer hope it helps! :)
You want to compare the malleability of
two metals. Plan an investigation that would allow you to determine
which metal is more malleable .
The temperature and the strength of the metallic link are the two most crucial variables that can impact how malleable a metal or alloy is.
What is metal ?A metal is a substance that has a shiny look when freshly processed, polished, or shattered, and conducts electricity and heat rather effectively. Generally speaking, metals are malleable and ductile.
The amount of pressure that a metal can sustain without breaking can be used to gauge its malleability. Varied metals have different degrees of malleability because of variations in their crystal structures.
The temperature of the metal and the strength of the metallic connection are the two parameters that define how malleable a metal or metal alloy will be.
Thus, The kind of the metallic connection can have a significant impact on how easily metal atoms can rearrange themselves.
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How many moles of sodium are present in 17 g of Na?
What is the number of moles in 60g of Na2SO4?
How many moles are there in 93.5g of CO2?
How many moles are there in 25.6g of Sodium Nitrate?
Determine the number of particles in .75 mol of calcium hydroxide
Answer:
1. 0.74mol
2. 0.42mol
3. 2.125mol
4. 0.301mol
5. 4.52 × 10^23 particles
Explanation:
Number of moles (n) in a substance can be found using the formula:
mole (n) = mass/molar mass
Using this formula, the following moles are calculated:
1. Molar of Na = 23g/mol
mole = 17/23
mole = 0.74mol
2. Molar mass of Na2SO4 = 23(2) + 32 + 16(4)
= 46 + 32 + 64
= 142g/mol
Mole = 60/142
mole = 0.42mol
3. Molar mass of CO2 = 12 + 16(2)
= 12 + 32
= 44g/mol
mole = 93.5/44
mole = 2.125mol
4. Molar mass of sodium nitrate (NaNO3) = 23 + 14 + 16(3)
= 23 + 14 + 48
= 85g/mol
mole = 25.6/85
mole = 0.301mol
5. Number of particles in one mole of a substance is 6.022 × 10^23 particles. Hence, in 0.75mol of calcium hydroxide (Ca(OH)2, there will be;
0.75mol × 6.02 × 10^23
= 4.515 × 10^23
= 4.52 × 10^23 particles
Someone please help i don’t have much time left
Answer: Energy of reactants = 30, Energy of products = 10
Exothermic
Activation energy for forward reaction is 10.
Explanation:
Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and [tex]\Delta H[/tex] for the reaction comes out to be negative.
Energy of reactants = 30
Energy of products = 10
Thus as energy of the product < energy of the reactant, the reaction is exothermic.
Activation energy [tex](E_a)[/tex] is the extra energy that must be supplied to reactants in order to cross the energy barrier and thus convert to products.
[tex]E_a[/tex] for forward reaction is (40-30) = 10.
which type of bond involves 2 different metals?
A. ionic
B. Covalent
C.Metallic
D. Bonding would not occur
Answer:
iconic bond is the answer
I hope it helps you ✌
A brown dye has a percent composition of 62.41% C, 5.24% H, and 32.36% N by mass with a molar mass of 346.40 g/mol. Determine the molecular formula of the dye
The molecular formula : C₁₈H₁₈N₈
Further explanationGiven
62.41% C, 5.24% H, and 32.36% N
Required
The molecular formula
Solution
mol ratio
C : 62.41/12.0096 = 5.1967
H : 5.24/1.00784 = 5.1992
N : 32.36/14.0067 = 2.310
Divide by 2.310(smallest)
C : 5.1967/2.31=2.25
H : 5.1992/2.31 = 2.25
N : 2.31/2.31 = 1
Multiplied by 4
C : H : N = 9 : 9 : 4
The empirical formula : C₉H₉N₄
(C₉H₉N₄)n=346.40 g/mol
(12.0096 x 9 + 1.00784 x 9 + 14.0067 x 4)n=346.4
(108.0864+9.07056+56.0268)n=346.4
(173.184)n=346.4
n=2
The molecular formula : C₁₈H₁₈N₈
A student prepared several aqueous sodium chloride (NaCl) solutions to observe boiling point elevation at various molal concentrations, however, several errors were made throughout the procedure. Determine whether these errors would cause the observed boiling point to be increased or decreased relative to the expected boiling point, based on the procedure, or have no effect on the experimental results.
The question is incomplete, the complete question is;
A student prepared several aqueous sodium chloride (NaCl) solutions to observe boiling point elevation at various molal concentrations, however, several errors were made throughout the procedure. Determine whether these errors would cause the observed boiling point to be increased or decreased relative to the expected boiling point, based on the procedure, or have no effect on the experimental results.
* The flask is washed with water but not thoroughly dried before preparing the solution
* The mass of NaCl used to prepare the solution is 5.400 grams instead of 4.400 grams
* Some of the prepared solution splashes out of the flask prior to observation of the boiling point
* When making the salt solution, 55.0 milliliters of water is added instead of 50.0 milliliters
Answer:
The flask is washed with water but not thoroughly dried before preparing the solution - decrease
The mass of NaCl used to prepare the solution is 5.400 grams instead of 4.400 grams
-increase
Some of the prepared solution splashes out of the flask prior to observation of the boiling point- have no effect
When making the salt solution, 55.0 milliliters of water is added instead of 50.0 milliliters- decrease
Explanation:
If the flask is washed but not dried, then the solution will be further diluted than expected. As a result of this further dilution, the observed boiling point will be less than the expected boiling point because the boiling point depends on the solution's concentration.
If more solute is added than expected, the concentration of the solution is increased and the boiling point also increases above the expected boiling point due to the increase in amount of solute present.
If some of the solution splashes out of the flask prior to boiling, the boiling point is not affected because the concentration of the solution was not altered. The boiling point only changes when the concentration of the solution is changed.
If 55 ml of water is added instead of 50 ml, the solution is now more dilute than expected thereby reducing the concentration of the solution and the boiling point. Remember that, as the concentration of the solution decreases, the boiling point decreases accordingly.
In a space shuttle, the Carbon dioxide, CO2 that the crew exhales is removed from the air by a reaction within canisters of Lithium Hydroxide, LiOH. The LiOH is only 85% efficient. On average, each astronaut exhales around 20.0 mol of CO2 every day. What volume of water is produced when the CO2 reacts with the excess LiOH
Answer:
What volume of water is produced when the CO2 reacts with the excess LiOH
X = 360 mL H2O
Explanation:
CO2 (g) + 2 LiOH(s) ⇒ Li2CO3 (aq) + H2O(l)
20.0 mol excess x g
X = 360 mL H2O
x mL H20 = 20.0 mol CO2 (1 mol H2O /1 mol CO2)(18 g H2O/1 mol H2O)
(1 mL H2O /1 g H2O)
X = 360 mL H2O
A 1.0 mol sample of he(g) at 25 is mixed with a 1.0 mol sample of Xe(g) at 50 C. What would be the changes in average kineeteic energy and the average speed of the Xe atoms that will occur as the mixture approaches thermal equilibrium?
Answer:
Explanation:
The average kinetic energy for an ideal gas is directly proportional to the temperature. The average kinetic energy of the gas is a measure of the temperature of the gas molecule
Also, the average speed is usually proportional to the square root of temperature.
Similarly, there is a noticeable increase in K.E and speed in regard to temperature but sometimes it is not usually proportional.
However, provided that there is more temperature in Xe as compared to He, then after the mixture of both takes place at equilibrium; the temperature tends to fluctuate between (25 - 50)°C
Thus, since there is a decrease in temperature in Xe, both the average kinetic energy as well as the speed too will also decrease.
How many grams of sodium chloride should you theoretically produce if you start with 5.00 grams of calcium chloride and excess sodium carbonate? (answer in numbers only - no units or words)
Answer:
5.27 g of NaCl
Explanation:
The balanced equation for the reaction is given below:
Na₂CO₃ + CaCl₂ —> 2NaCl + CaCO₃
Next, we shall determine the mass of CaCl₂ that reacted and the mass of NaCl produced from the balanced equation. This can be obtained as follow:
Molar mass of CaCl₂ = 40 + (35.5×2)
= 40 + 71
= 111 g/mol
Mass of CaCl₂ from the balanced equation = 1 × 111 = 111 g
Molar mass of NaCl = 23 + 35.5
= 58.5 g/mol
Mass of NaCl from the balanced equation = 2 × 58.5 = 117 g
Summary:
From the balanced equation above,
111 g of CaCl₂ reacted to produce 117 g of NaCl.
Finally, we shall determine the theoretical yield of NaCl. This can be obtained as follow:
From the balanced equation above,
111 g of CaCl₂ reacted to produce 117 g of NaCl.
Therefore, 5 g of CaCl₂ will react to produce = (5 × 117)/111 = 5.27 g of NaCl.
Thus, the theoretical yield of NaCl is 5.27 g.
HELLOSOEOODORODODODORRLKRKLRLRLF
Answer:
I'd say maybe Dangerous? I hope this helps
Answer:
golden is sometimes referred to as shiny and beatitful
Explanation:
A sample of PCl5 weighting 2.69 gram was placed in 1.00 Litter container and completely vaporized at 250C. The pressure observed at that temperature was 1.00 atm. The possibility exists that some of the PCl5 dissociated according to PCl5 (g) ! PCl3 (g) Cl2 (g) . What must be the partial pressures of PCl5 PCl3 and Cl2 under these experimental conditions
Answer:
Partial pressures:
PCl₅ = 0.558 atm
PCl₃ = 0.22 atm
Cl₂ = 0.22 atm
Explanation:
From the given information:
The number of moles of PCl₅ associated with the evaporation is:
[tex]n_{PCl_5}= \dfrac {weight \ of \ PCl_5} {M.Wt. \ of \ PCl_5}[/tex]
[tex]n_{PCl_5}= \dfrac {2.69 \ g} {208.5 \ g/mol}[/tex]
[tex]n_{PCl_5}= 0.013 \ mol[/tex]
Temperature of the gas = 250° C = (250 + 273.15) K
= 523.15 K
Using the Ideal gas equation to determine the pressure exerted by the completely vaporized PCl₅
PV = nRT
[tex]P = \dfrac{nRT}{V}[/tex]
[tex]P = \dfrac{0.0013 \ mol \times 0.082 \ Latm^0 K^{-1} . mol ^{-1} \times 523.15 \ K}{1.0 \ L}[/tex]
P = 0.558 atm
Thus, at 250° C, decomposition of PCl₅ occurs.
In the container, PCl₅ decomposes to PCl₃ and Cl₂.
i.e.
[tex]PCl_{5(g)} \to PCl_{3(g)}+ Cl_{2(g)}[/tex]
Using Dalton's Law:
[tex]P_{total } =P_1 + P_2+P_3 +...[/tex]
[tex]P_1 = P_{Total} \times X_1[/tex]
where;
X = mole fraction
Then, the total no. of moles in the container is:
[tex]n = \dfrac{PV} {RT}[/tex]
[tex]n = \dfrac{1\ atm \times 1.0\ L}{0.0821 \ L \ atm \ K^{-1}.mol \times 523.15\ K}[/tex]
n = 0.023 mol
Now, the container contains a total amount of 0.023 mol where initially 0.013 mol are that of PCl₅ and remaining 0.005 mol of PCl₃ and 0.005 mol of Cl₂.
Thus, the partial pressure of PCl₃ is:
[tex]P__{PCL_3} }= P_{total} \times \dfrac{no. \ of \ moles \ of PCl_5}{total \ no. \ of \ moles}[/tex]
[tex]P__{PCL_3}} = 1 \ atm \times \dfrac{0.005}{0.023}[/tex]
[tex]P__{PCL_3}} = 0.22 \ atm[/tex]
Thus, since the no of moles of PCl₃ and Cl₂ are the same, then the partial pressure for Cl₂ is = 0.22 atm
Classify each of the following compounds as a strong acid, weak acid, strong base, or weak base, and write the Ka expression for any weak acid or weak base:
1. [ Select ] ["strong base", "weak base", "strong acid", "weak acid"] LiOH
2. [ Select ] ["weak acid", "strong acid", "strong base", "weak base"] HF
3. [ Select ] ["strong acid", "weak acid", "strong base", "weak base"] HCl
4. [ Select ] ["weak base", "strong base", "weak acid", "strong acid"] NH3
Ka expression: [ Select ] ["[H+][F-] / [HF]", "[Li+][OH-]/ [LiOH]", "[H+][Cl-} / [HCl]", "[NH4+] / [NH3]", "[HF] / [H+][F-}", "[LiOH] / [Li+][OH-]", "[HCl] / [H+][Cl-}", "none"]
Calculate the concentration of OHLaTeX: -? in a solution that has a concentration of H+ = 7 x 10LaTeX: -?6 M at 25°C. Multiply the answer you get by 1010 and enter that into the field to 2 decimal places.
Answer:
See explanation below
Explanation:
There are several ways to know if an acid or base is strong. One method is calculating the pH. If the pH is really low, is a strong acid, and if it's really high is a strong base.
However we do not have a pH value here.
The other method is using bronsted - lowry theory. If an acid is strong, then his conjugate base is weak. Same thing with the bases.
Now, Looking at the 4 compounds, we can say that only two of them is weak and the other two are strong compounds. Let's see:
LiOH ---> Strong. If you try to dissociate :
LiOH ------> Li⁺ + OH⁻ The Li⁺ is a weak conjugate acid.
HF -----> Weak
HF --------> H⁺ + F⁻ The Fluorine is a relatively strong conjugate base.
HCl -----> Strong
This is actually one of the strongest acid.
NH₃ ------> Weak
Now writting the Ka and Kb expressions:
Ka = [H⁺] [F⁻] / [HF]
Kb = [NH₄⁺] [OH⁻] / [NH₃]
Finally, to calculate the [OH⁻] we need to use the following expression:
Kw = [H⁻] [OH⁻]
Solving for [OH⁻] we have:
[OH⁻] = Kw / [H⁺]
Remember that the value of Kw is 1x10⁻¹⁴. So replacing:
[OH⁻] = 1x10⁻¹⁴ / 7x10⁻⁶
[OH⁻] = 1.43x10⁻⁹ M
And now, multiplying by 10¹⁰ we have:
[OH⁻] = 1.429x10⁻⁹ * 1x10¹⁰
[OH⁻] = 14.29Hope this helps
Strong acids and bases are those which completely ionized in body fluid, and weak acids and bases are those who does not completely ionized in body fluid.
Ka expression is used to differentiate between strong and weak acids.
Which are strong acids and base and weak acids and bases?LiOH - strong baseHF - weak acidHCl - strong acidNH3 - weak baseWhat are the Ka expression of the following?Weak acid – HF[tex]\bold{\dfrac{[H+][F-]}{[HF]}}[/tex]
Weak base – NH3[tex]\bold{\dfrac{[NH_4^+] [OH^-]}{[NH_3]} }[/tex]
Calculate the concentration of OH?Given, [tex]\bold{ [H^+]=1\times10^-^6\; at \;25^oC}[/tex]
We know, [tex]\bold{ [H^+]\times[OH^-]=1\times10^-^6\; at \;25^oC}[/tex]
[tex]\bold{[OH^-]=\dfrac{1\times10^-^1^4}{6.2\times10^-^6} = 1.43\times10^-^9}[/tex]
Now, multiplying the value by [tex]10^1^0[/tex]
[tex]\bold{( 1.429\times10^-^9) \times 1\times10^1^0= 14.29}[/tex]
Thus, the value is 14.29.
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What is another name for infrared energy? Choose all that apply.
Question 1 options:
Microwave energy
Visible light
Thermal energy
Heat
Answer: not 100% but maybe Visable Light...sorry if thats wrong
Explanation:
Thermal energy is the another name for infrared energy.
What is infrared radiation?Infrared radiation is a type of radiant energy that is not visible to human eyes but we can feel as heat energy.
Infrared radiation (IR), also known as thermal radiation. It is that band of energy in the electromagnetic radiation spectrum with wavelengths between 780 nm and 1 mm so we can conclude that thermal energy is the another name for infrared energy.
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How was Bohr's atomic model different from those of previous scientists?
Answer:
Bohr placed the electrons in distinct energy levels. Rutherford described the atom as consisting of a tiny positive mass surrounded by a cloud of negative electrons. Bohr thought that electrons orbited the nucleus in quantized orbits. Also, rutherfords was just a hypothesis while Bhor took the time to make his an experiment
Hydrogen peroxide is a versatile chemical, its uses include bleaching wood pulp and fabrics and substituting for chlorine in water purification. One reason for its versatility is that it can be either an oxidizing or reducing agent. For the following reactions, identify whether hydrogen peroxide is an oxidizing or reducing agent.
a) H2O2 (aq) + 2 Fe2+ (aq) + 2 H+ + 2H20 (1) + 2 Fe3+(aq)
b) 5 H2O2 (aq) + 2 MnO4 (aq) + 6 H+ (aq) → 8 H20 (1) + 2 Mn2+ (aq) + 5 O2 (g)
Answer:
Explanation:
a )
H₂O₂ (aq) + 2 Fe²⁺ (aq) + 2 H⁺ = 2H20 (l) + 2 Fe³⁺(aq)
Here oxidation number of Fe is increasing from + 2 to + 3 so it is being oxidized . Hence H₂O₂ is acting as oxidizing agent here .
b )
5 H₂O₂ (aq) + 2 MnO₄⁻¹ (aq) + 6 H⁺ (aq) → 8 H20 (l) + 2 Mn⁺² (aq) + 5O₂ (g)
In this reaction, oxidation number of Mn is reducing from + 7 to + 2 so it is being reduced . Here H₂O₂ is acting as reducing agent .
7. You are about to perform some intricate electrical studies on single skeletal muscle fibers from a gastronemius muscle. But first, you must prepare 6L of a 170 mM NaCl solution in which to bath the isolated muscle during your studies. How many grams of NaCl must you weigh out on the lab balance to prepare this bath solution
Answer:
58.61 grams
Explanation:
Taking The molecular weight of NaCl = 58.44 grams/mole
Determine how many grams of NaCl to prepare the bath solution
first we will calculate the moles of NaCl that is contained in 6L of 170 mM of NaCI solution
= ( 6 * 170 ) / 1000
= 1020 / 1000 = 1.020 moles
next
determine how many grams of NaCl
= moles of NaCl * molar mass of NaCl
= 1.020 * 58.44
= 58.61 grams
A change of state is a(n)
process.
A. irreversible
B. reversible
Answer:
Changes of states are reversible, you can go from a solid to liquid and liquid to solid.Answer:
Reversible
Explanation:
Changes of state are physical changes in matter. Common changes of the state include melting, freezing, sublimation, deposition, condensation, and vaporization.
The reactants of two chemical equations are listed.
Equation 1: AgNO3 + Zn
Equation 2: AgNO3 + MgCl2
Based on the type of reaction, which reaction can be used to extract silver metal from silver nitrate solution?
Answer: Equation 1, because Zn being more reactive, replaces Ag from AgNO3
Explanation: I got it right on the quiz and it replaces it
Identify the true statements about surface tension. Molecules along the surface of a liquid behave differently than those in the bulk liquid. Water forming a droplet as it falls from a faucet is a primary example of surface tension. Surface tension increases as the temperature of the liquid rises. Cohesive forces attract the molecules of the liquid to one another. Mercury has a lower surface tension than water.
Answer:
Molecules along the surface of a liquid behave differently than those in the bulk liquid.
Cohesive forces attract the molecules of the liquid to one another.
Water forming a droplet as it falls from a faucet is a primary example of surface tension.
Explanation:
Surface tension is the force that stretches the liquid surface. This force acts normal to the surface. It is the downward force that acts on the surface of the liquids which is due to the cohesive forces of the liquids.
The water molecules are bonded by a strong hydrogen bond force which is between hydrogen atom and the electronegative oxygen atom. At the surface the water molecules are attracted strongly by other water molecules which lies below the surface and are stretched at the surface. Thus the water molecules at the surface acts differently than in the bulk liquid.
Mercury have a strong cohesive force than the water and have a higher surface tension force than the water.
Surface water acquires minimum surface area, hence acquiring spherical shape of water.
Which pair of elements would you expect to exhibit the greatest similarity in their physical
and chemical properties?
Select one:
O a. No
O b. Mg, Al
O c. Br, Kr
O d. As, Br
O e. I, AT
Answer:
e. I, At
Explanation:
Hello!
In this case, since the periodic trends of a series of elements belonging to the same group towards physical and chemical properties tend to be the same when closer in period, we notice that Mg and Al, Br and Kr and As and Br are close but in period, not in the same group; therefore e. I, At, iodine and astatine, are going to tend to exhibit the greatest similarity in their physical and chemical properties.
Best regards!
what state of matter travels in straight lines
Answer:
light
Explanation:
light is plasma, which is a state of matter
help now plsss I really need help !!!!
Answer:
4
Explanation:
the one you ARE ON
How many orbitals in an atom can have each of the following designations:
(a) 1s;
(b) 4d;
(c) 3p;
(d) n=3?
Answer:
(a) 1s; has one orbital
(b) 4d; has five orbitals
(c) 3p; has three orbitals
(d) n=3 has nine orbitals
Explanation:
Electrons in an atom are always in constant motion, making it hard to predict there exact position. However, the most probable locations electrons can be be found are described with the terms shells, subshells and orbitals. A shell contains subshells and orbitals are found within subshells. The shells are given names such as K, L, M, N, which correspond to the principal quantum numbers, n = 1, 2, 3, and 4 respectively. There are 4 major types of subshells that can be found in a shell. They are named as s, p, d, f. Each subshell is composed of several orbitals.
a. 1s; the s subshell has only one orbital. Therefore, the 1s subshell has one orbital
b. 4d; the d subshell has five orbitals. Therefore, the 4d subshell has five orbitals
c. 3p; the p subshell has three orbitals. Therefore, the 3d subshell has three orbitals
d. n = 3; the shell with n = 3 has the following subshells, 3s, 3p, 3d.the number of orbitals will be 1 + 3 + 5 = 9 orbitals. Therefore, the number of orbitals in n = 3 is nine orbitals
ASAP I WILL GIVE BRAINLIEST The diagram shows a lever. What is the mechanical advantage of the lever? O 2 03 3 m 6 m mi 0 9
Answer:
A) 2
Explanation:
Answer:
2, i got it right thanks to the other user :) <3
Explanation:
Benzophenone has a normal freezing point of +48.1 oC, with freezing point depression constant Kfpt = − 9.78 oC/m. A 0.1500 molal solution of ionizing salt had a freezing point of +44.0 oC. What is the van't Hoff (ion dissociation) constant i for this salt? (i.e., the average number of ions produced in the solution.) Report 3 significant digits.
Answer:
i = 2.79
Explanation:
The excersise talks about the colligative property, freezing point depression.
Formula to calculate the freezing point of a solution is:
Freezing point of pure solvent - Freezing point of solution = m . Kf . i
Let's replace data given. (i = Van't Hoff factor, numbers of ions dissolved in solution)
48.1°C - 44°C = 0.15 m . 9.78°C/m . i
4.1°C / (0.15 m . 9.78°C/m) = i
i = 2.79
In this case, numbers of ions dissolved can decrease the freezing point of a solution, which is always lower than pure solvent.
A reaction between liquid reactants takes place at in a sealed, evacuated vessel with a measured volume of . Measurements show that the reaction produced of sulfur hexafluoride gas. Calculate the pressure of sulfur hexafluoride gas in the reaction vessel after the reaction. You may ignore the volume of the liquid reactants. Round your answer to significant digits.
Answer:
0.41 atm
Explanation:
A reaction between liquid reactants takes place at 10.0 °C in a sealed, evacuated vessel with a measured volume of 5.0 L. Measurements show that the reaction produced 13. g of sulfur hexafluoride gas. Calculate the pressure of sulfur hexafluoride gas in the reaction vessel after the reaction. You may ignore the volume of the liquid reactants. Round your answer to 2 significant digits.
Step 1: Given data
Temperature (T): 10.0 °CVolume of the vessel (V): 5.0 LMass of sulfur hexafluoride gas (m): 13. gStep 2: Convert "T" to Kelvin
We will use the following expression.
K = °C + 273.15
K = 10.0 °C + 273.15 = 283.2 K
Step 3: Calculate the moles (n) of SF₆
The molar mass of SF₆ is 146.06 g/mol.
13. g × 1 mol/146.06 g = 0.089 mol
Step 4: Calculate the pressure (P) of SF₆
We will use the ideal gas equation.
P × V = n × R × T
P = n × R × T/V
P = 0.089 mol × (0.0821 atm.L/mol.K) × 283.2 K/5.0 L = 0.41 atm
