It can lower and expand the melting point if the sample is not dried completely.
Impurities may be present in a sample if the drying process is not complete. The melting point is decreased and widened when contaminants are still present in a sample. For instance, if a substance's usual melting point range is 104C to 106C, improper drying could result in the presence of impurities, which would lower and widen the melting point range to something like 85C to 97C.
To know more about melting point click here:
https://brainly.com/question/25777663
#SPJ4
A cube with 34.16 inch sides of an unknown material weighs 6.85 kg. What is this material'sdensity in g/mL? (Hint: 1 in = 2.54 cm)
From the calculations above, the density of the material is 0.01g/mL
To solve this problem, we have to calculate the volume of the cube, but first of all, we should convert the unit from in to cm.
Conversion from Inches to CentimeterLet us convert the unit of the side length from inches to centimeter.
[tex]\begin{gathered} 1in=2.54\operatorname{cm} \\ 34.16in=\text{xcm} \\ x=34.16\times2.54 \\ x=86.7664\operatorname{cm} \end{gathered}[/tex]Volume of a CubeThe volume of a cube is given as
[tex]\begin{gathered} v=l^3 \\ l=\text{side length} \end{gathered}[/tex]let's substitute the values and solve for the volume.
[tex]\begin{gathered} v=l^3 \\ v=(84.7664)^3 \\ v=653212.87\operatorname{cm}^3 \end{gathered}[/tex]Note;
[tex]\begin{gathered} 1\operatorname{cm}^3=1mL \\ 653212.87\operatorname{cm}^3=653212.87mL \end{gathered}[/tex]Now that we have the volume of the material, let us calculate it's density
Density of a materialThe density of a material can be calculated as
[tex]\rho=\frac{\text{mass}}{\text{volume}}[/tex]But the given mass is in kg and we are asked to find the density in g/mL
Conversion of mass from kg to g[tex]\begin{gathered} 1\operatorname{kg}=1000g \\ 6.85\operatorname{kg}=6850g \end{gathered}[/tex]We can substitute this information and calculate for the density.
[tex]\begin{gathered} \rho=\frac{\text{mass}}{\text{volume}} \\ \rho=\frac{6850}{653212.87} \\ \rho=0.010\text{ g/mL} \end{gathered}[/tex]From the calculations above, the density of the material is 0.01g/mL
What role does water play in assembling and decomposing polysaccharides?
INFORMATION:
We need to determine the role of the water in assembling and decomposing of polysaccharides
STEP BY STEP EXPLANATION:
To determine it, we need to know the process of decomposing polysaccharides:
Process of decomposing polysaccharides:
Polysaccharides can be broken down, by hydrolysis of the glycosidic bonds between residues, into smaller polysaccharides as well as disaccharides or monosaccharides. Its digestion within the cells, or in the digestive cavities, consists of a hydrolysis catalyzed by digestive enzymes (hydrolases) generically called glycosidases, which are specific for certain polysaccharides and, above all, for certain types of glycosidic bond. Thus, for example, the enzymes that hydrolyze starch, whose bonds are of the type called α(1→4), cannot break down cellulose, whose bonds are of the β(1→4) type, although in both cases the monosaccharide be the same. Glycosidases that digest polysaccharides, which may be called polysaccharides, generally break every other bond, thus releasing disaccharides and leaving other enzymes to complete the job later.
Now, knowing that we can decompose polysaccharides by hydrolysis and using that hydrolysis is
in which the water molecule divides and breaks one or more chemical bonds and its atoms go on to form a union of another chemical species, we can say that water plays the role of divide their molecules and break one or more chemical bonds so that their atoms form a union and the polysaccharides break down into disaccharides or monosaccharides.
ANSWER:
water plays the role of divide their molecules and break one or more chemical bonds so that their atoms form new unions and the polysaccharides break down into disaccharides or monosaccharides.
What is the molarity of a 0.75 L solution that contains 9.2 g of NaCl?
The molarity of the solution is 0.209 M.
Molarity is an expression of the concentration of a compound and it is represented in mole/liter.
So, we need to know how many moles tha sample has.
- First, with the molar mass of the NaCl molecule we calculate the number of moles conteined in 9.2g of NaCl:
NaCl molar mass= 58.44g/mol
[tex]\frac{9.2g\text{ . 1mol}}{58.44g}=\text{ 0.157 moles}[/tex]- Second, molarity is expressed in 1 liter, so we calculate the number of moles that are conteined in 1 liter:
[tex]\frac{1L\text{ . 0.157moles}}{0.75L}=0.209\text{ moles}[/tex]- So, the molarity of the solution is 0.209 M.
Which of the following is a correct example of physical change?1. Burning a piece of wood2. Rusting of an object's surface3. Cutting up a piece of paper4. Changing the chemical identity of a substance
Let's talk about physical and chemical changes:
A Physical change is a type of change where the physical properties of matter change. A change of state of matter, change in colour, odour, solubility, etc. all are examples of physical change. During a physical change, neither the composition nor the chemical nature of matter is changed.
A chemical change is a change of materials into another, new materials with different properties and one or more than one new substances are formed. It results when a substance combines with another to form a new substance (synthesis or either decomposes to form more substances).
According to the definitions given, then from the options given the correct example of physical change is 3. Cutting up a piece of paper.
Beneath each word equation, write and balance the formula equation. Rememberthat several elements exist as diatomic molecules. Dinitrogen pentaoxide -> nitrogen +oxygen
Dinitrogen pentaoxide ===> nitrogen + oxygen
Dinitrogen pentaoxide = N2O5
Nitrogen (remember diatomic) = N2
Oxygen (remember diatomic) = O2
The reaction:
N2O5 ===> N2 + O2
To balance, we must have the same number of atoms on both sides.
So, you must add some numbers in front of each molecule.
Answer: 2 N2O5 ===> 2 N2 + 5 O2 (the balanced reaction)
A mixture of krypton and neon gas is compressed from a volume of 79.0L to a volume of 71.0L, while the pressure is held constant at 17.0atm. Calculate the work done on the gas mixture. Round your answer to 2 significant digits, and be sure it has the correct sign (positive or negative).
Using the fact that:
[tex]W=P\Delta V[/tex]We could replace our values as follows:
[tex]\begin{gathered} W=17atm\cdot(71L-79L) \\ W=17atm\cdot(-8L) \\ W=-136J \end{gathered}[/tex]As you can see, the work done is negative since the gas is being compressed. Therefore,
The work done is -136J.
In kJ, the answer is -0.136kJ. Rounded to 2 significant digits, this is -0.14kJ
Mg(OH)₂ + 2HNO₃ → Mg(NO₃)₂ + 2H₂OWhy is this a balanced chemical equation?
The quemical equation is balanced because the total number of each element on the reactants side (to the left of the arrow) is equal to the total number of each element on the products side (to the right of the arrow).
For example, on the reactants side there are:
- 1 Mg
- 8 O
- 4 H
- 2 N
And, on the products side there are:
- 1 Mg
- 2 N
- 8 O
- 4 H
A student drew a model of two liquids. One hot and one cold. How would the student draw this? Choose all that applies?
A. Models should show two separate containers of liquid.
B. Models should show one container of liquid.
C. There should be something to represent the molecules in the liquid.
D. There should be something to represent air in the liquid.
E. The student should put longer arrows on the cold liquid and short arrows on the warm liquid. The arrows show the speed of the molecular movement.
F. The student should put shorter arrows on the cold liquid and longer arrows on the warm liquid. The arrows show the speed of the molecular movement.
G. There should be a key to tell what the arrows represent and how the molecules are represented.
Please answer ASAP! Will reward.
Models should show two separate containers of liquid and There should be a key to tell what the arrows represent and how the molecules are represented.
It is the lowest point in the substance and has chemical elements. Atoms don't exist on their own; instead, they combine to create ions and molecules, which combine to create the substances that we can see, feel, and touch.
One or more atoms joined together by covalent (chemical) bonds make up molecules. Atoms may be seen as circles with a central nucleus (consisting of protons and neutrons) and one or more concentric circles around it that represent the "shells" or "levels" in which the electrons surrounding the atom's nucleus are placed as well as marks that distinguish the electron. every level
To know more about molecules visit : brainly.com/question/11405437
#SPJ1
What is the %v/v when 17.8mL is Acetic Acid is dissolved in 40.8mL of water?
Answer:
30.4 %.
Explanation:
Let's see the volume percentage (% v/v) formula:
[tex]Percent\text{ volume=}\frac{volume\text{ of solute}}{volume\text{ of solution}}\cdot100\text{ \%,}[/tex]in this case, the solute is acetic acid and the solution is the solute and solvent (which is water). Based on this logic, the volume of solute is 17.8 mL, whereas the volume of solution is the sum of the volumes of solute and solvent ( 17.8 mL + 40.8 mL = 58.6 mL), so we just have to replace the values that we have in the formula:
[tex]\begin{gathered} Percent\text{ volume=}\frac{17.8\text{ mL}}{58.6\text{ mL}}\cdot100\%, \\ \\ Percent\text{ volume=30.4\%.} \end{gathered}[/tex]The answer would be 30.4 %.
1. What are the similarities and differences between Electronegativity and Ionization Energy?
Electronegativity and Ionization energies are similar because they both explain the interactions between an atomic nucleus and electrons.
However, they are different because electronegativity explains the attraction of electrons while the ionization energy is about the removal of electrons from an atom.
HELP ME OUT PLEASE!!!
Why is it significant to strip only one side of the wire?
C*(UPQuestion 6 of 26šiWhich of the following sets of quantum numbers is not allowed?A) n = 1, l = 0, ml = 0B) n = 4, f = 0, ml = -1C) n = 3, l = 1, ml = 0D) n = 2,1 = 0, ml = 0E) n = 3, l = 2, ml = -2
Let's analyze option B:
Given that n=4, l=0 and ml=-1, we could draw:
If we have n=4, l=0, that means that the electron configuration ends at 4s. As you can notice, "s" orbital can only adquire one pair of electrons and ml can only be 0. In the answer option this is -1, so this option is not correct.
The answer is B.
How can a reaction with a negative value of ▲ Gº be described?OA. As exothermicOB. As spontaneousOC. As endothermicOD. As nonspontaneous
Answer: A negative value of ΔG describes a spontaneous reaction (letter B).
Explanation:
The question requires us to choose the correct option that describes a reaction with negative value of free energy change (ΔG).
Free energy (G) refers to the energy that is available to a system to do work. It refers to the spontainety of a chemical reaction rather than the heat energy that is released or absorbed by the system as the reaction occurs.
As the spontainety of a reaction is determined by the enthalpy and entropy changes (ΔH and ΔS, respectively) that occur in the system, free energy change (ΔG) can be defined in terms of ΔH and ΔS:
[tex]ΔG^°=ΔH^°-TΔS^°[/tex]A spontaneous chemical reaction is one that releases energy, thus the reaction will be spontaneous when ΔG value is negative.
Answer:
Exothermic is the best choice.
Explanation:
A negative sign for ΔG means that energy was released from the system. The term for that is exothermic (exo means outside). Endothermic reaactions absorb energy from their surroundings. [They are no fun.] Spontaneous reactions can be endothermic or exothermic. Most will be exothermic, so it is tempting to select this as the answer. But all exothermic reaction have a negative ΔG, so it is the best choice.
Calculate the [H+] given a pH of 2.80
Answer:
The [H+] is 1.6x10^-3 M.
Explanation:
1st) We can calculate the concentration of H+, using the pH formula:
[tex]\begin{gathered} pH=-log\lbrack H^+\rbrack \\ 2.80=-log\lbrack H^+\rbrack \\ 10^{(-2.80)}=\lbrack H^+\rbrack \\ 1.6*10^{-3}M=\lbrack H^+\rbrack \end{gathered}[/tex]So, the [H+] is 1.6x10^-3 M.
Which of the following relates the volume of a gas to the number of molecules of a gas?Group of answer choicesBoyles's lawCharles's lawDalton's lawGrahams's lawAvogadro's hypothesis
Explanation:
Avogadro's hypothesis or Avogadro's law states that two volumes (equal volumes) of any gas at the same temperature and pressure contain the same number of molecules.
Answer: Avogadro's hypothesis
How would you prepare 250 mL of 0.125 M HCl from concentrated HCl (aq) that is 38.0% by mass with a density of 1.19 g/mLnote: find moles in 250 mL of 0.125 HCl
Answer
250 mL of 0.125 M HCl can be prepared from concentrated HCl (aq) that is 38.0% by mass with a density of 1.19 g/mL by adding 2.49 mL of HCL(38%) into a small quantity of water, mix to disperse; then dilute with solvent water up to but not to exceed the total needed volume of solution (in this case 250 mL).
Explanation
The problem can be solve in four steps:
Step 1: Calculate the number of moles in 38.0% by mass of HCl.
[tex]\begin{gathered} \text{HCl (38.0}\%)\text{ }=(\frac{38g\text{ HCl}}{100\text{ g solution}})=(\frac{x\text{ moles HCl}}{1.0\text{ Liter Solution}}) \\ \\ \Rightarrow Moles\text{ of HCl in 38 grams }=\frac{38g\text{ HCl}}{36\text{ g/mol}}=1.06\text{ mole HCl} \end{gathered}[/tex]Step 2: The volume of the 38.0% by mass HCl solution.
Volume of solution in Liters containing 1.06 mole of HCl =
[tex]\frac{Mass}{D\text{ensity}}=\frac{100g}{1.19gmL^{-1}^{}}=84.03\text{ mL HCl(38.0}\%)\text{ }=0.084\text{ L HCl(38.0}\%)[/tex]Step 3: Calculate the molarity of HCl (38.0%)
[tex]\text{Molarity of HCl (38.0}\%)=\frac{Number\text{ of mole}}{Volume\text{ in liters}}=\frac{1.06\text{ mole HCl}}{0.084\text{ L HCl}}=12.62\text{ M}[/tex]Step 4: To calculate the volume of HCl (38.0%) required to prepare 250 mL of 0.125 M HCl.
Note: Formula weight of HCl = 36 g/mol
[tex]\begin{gathered} \text{Volume of HCl(38.0}\%)\text{ required }=\frac{(Molarity)(Volume)(Formula\text{ Weight)}}{(\text{Purity)(Specific Gravity)}} \\ \\ \text{Volume of HCl(38.0}\%)\text{ required }=\frac{(0.125\text{ M)})(250\text{ }mL)(36\text{ g/mol)}}{(0.38\text{)}(1.19\text{ g/mL)}} \\ \\ \text{Volume of HCl(38.0}\%)\text{ required }=\frac{(0.125\text{ M)})(0.250\text{ }L)(36\text{ g/mol)}}{(0.38\text{)}1.19\text{ g/mL)}} \\ \\ \text{Volume of HCl(38.0}\%)\text{ required }=\frac{1.125}{0.4522}=2.49\text{ mL} \end{gathered}[/tex]Therefore, 250 mL of 0.125 M HCl can be prepared from concentrated HCl (aq) that is 38.0% by mass with a density of 1.19 g/mL by adding 2.49 mL of HCL(38%) into a small quantity of water, mix to disperse; then dilute with solvent water up to but not to exceed the total needed volume of solution (in this case 250 mL).
Nitrogen dioxide reacts with water to produce nitric acid and nitrogen monoxide. How many grams of nitric acid can be prepared from 95.52 grams of nitrogen dioxide?
87.22grams
Explanations:The chemical reaction between Nitrogen dioxide and water to produce nitric acid and nitrogen monoxide is expressed as:
[tex]3NO_2+H_2O\rightarrow2HNO_3+NO[/tex]Determine the moles of nitrogen dioxide(NO2)
[tex]\begin{gathered} mole=\frac{mass}{molar\text{ mass}} \\ mole=\frac{95.52}{46.0055} \\ mole\text{ of NO}_2=2.076moles \end{gathered}[/tex]According to stoichiometric ratio, 3 moles of nitrogen dioxide produces 2moles of nitric acid, the moles of nitric acid required is expressed as;
[tex]\begin{gathered} moles\text{ of }HNO_3=\frac{2}{3}\times2.076 \\ moles\text{ of }HNO_3=1.384moles \end{gathered}[/tex]Determine the mass of nitric acid
[tex]\begin{gathered} mass\text{ of HNO}_3=mole\times molar\text{ mass} \\ mass\text{ of HNO}_3=1.384\times63.01 \\ mass\text{ of HNO}_3=87.22grams \\ \end{gathered}[/tex]Hence the mass of nitric acid required is 87.22grams
Calculate the theoretical pH at equivalence for this titration. Show all your work. 10.00mL of methanoic acid initial volume
According to the problem we are adding a 0.1 M solution of KOH to a 0.1 M solution of HCOOH. So, we are titrating a weak acid using a strong base.
The reaction that describes this titration is:
HCOOH (aq) + KOH (aq) <----> HCOOK (aq) + H₂O (l)
The reaction is 1 to 1, since all the coefficients are 1.
The equivalence point occurs when equal number of moles of acid reacts with equal number of moles of base.
Let's find the initial number of moles of metanoic acid that we had:
Initial number of moles of HCOOH = 10.00 mL * 0.1 mmol/mL
Initial number of moles of HCOOH = 1.00 mmol
In the equilibrium point we need the same number of moles of the strong base.
Moles of KOH =
Calculate the volume of 77.58 g of zinc (density=7.000 g/cm³).
Volume of 77.58 g of zinc is calculated as , volume= 11.08 cm^3
What is mass and volume?Mass measures the amount of matter in a substance and SI unit for mass is the kilogram. Volume measures the amount of space that a substance takes up and SI unit for volume is cubic meter. Volume of the object is directly proportional to its mass such that as the volume increases the mass of the object increases.
Given, mass of zinc = 77.58g
We know that density of zinc = 7g/cm^3
1cm^3 of zinc will move 7gm
Let volume be x
x= 77.58/7
Volume = 11.08 cm^3
To know more about volume of an element, refer
https://brainly.com/question/25736513
#SPJ13
Fe^2O^3Express your answer as an ion.
Answer:
[tex]Fe_2^{3+}O_3^{2-}.[/tex]Explanation:
Remember that the algebraic sum of the oxidation states of a compound must be zero.
Oxygen always has the oxidation state -2.
In this case, for Fe, we have two options of oxidation state (+2 and +3).
As the algebraic sum must be zero, and we have 3 oxygens in Fe2O3, multiplying -2 by 3, we obtain -6, so we need to find the oxidation state of Fe that sum with -6, the result is zero. If the oxidation state of Fe is +3, multiplying this number by the two Fe that we have, we obtain +6, so the algebraic sum is: -6 +6 = 0.
The ion form, in this case, will look like this:
[tex]Fe_2^{3+}O_3^{2-}.^[/tex]Order the following elements from smallest to largest
Answer: F, O, N, C, B
Explanation: The element with the greatest electronegativity will have the smallest radius because it holds the electrons closest to the nucleus. Fluorine is the most electronegative element (it is in the upper right of the periodic table), Francium is the lease (it is the lower left of the periodic table). With this knowledge, you should be able to recognize a trend in the periodic table associated with atomic radius size and electronegativity.
Which element is most likely to behave as a metalloid?NaArZnAs
A metalloid is an elements that has some characteristics of metal and other of non-metals. In a periodic table, it is somewhere in between the metals and non-metals.
Looking to a periodic table, we have Na to the far left, so it must has metal characteristics.
Ar is to the far right, it is a noble gas, so not metalloid.
Zn is quite close to the right side, however it is in the groups of transition metals, so it is still a metal and must have metal characteristics.
As is even more to the right, exactly where the metal characteristics of elements start to change to non-metals, so As is probably the one with metalloid characteristics.
Give 2 ways to distinguish between carbon(iv) oxide and carbon (ii) oxidedifferentiate the physical properties of the two oxides of carbon
You can note that the roman numerals in the parenthesis of carbon (IV) oxide and carbon (II) oxide indicate the oxidation state of carbon.
Remember that oxides are compounds that are formed with oxygen and another element, in this case, is carbon. It's important to clarify that the oxidation state of oxygen is always -2. The algebraic sum of the oxidation states must be zero.
One way to distinguish this is to write the oxidation state in every element and then, put these numbers on the other element. Let's see this with the example of carbon (IV) oxide (IV is 4):
And for carbon (II) oxide, we can do the same:
Carbon (IV) oxide is CO2 because the oxidation state of carbon is +4 and carbon (II) oxide is CO because the oxidation state of carbon is +2.
Between the physical properties of CO, we have that it's a colorless compound, at ambient temperature is a gas and it's odorless.
For CO2, it's a gas at an ambient temperature too, it's odorless too at low concentrations and it is denser than air.
Given that4 NH3 (g) + 5 O2(g) > 4 NO(g) + 6 H2O(g)If 8.20 moles of NH3 react with sufficient oxygen, how many moles of water should form?1. 6.11 moles2. 12.0 moles3. 22.0 moles4. 8.25 moles5. 15.1 moles
Answer:
[tex]12.3\text{ moles}[/tex]Explanation:
Here, we want to get the number of moles of water that would form
From the equation of reaction, 4 moles of ammonia produced 6 moles of water
However, 8.2 moles of ammonia will produce x moles of water
To get the value of x, we have it that:
[tex]\begin{gathered} \text{ 4 }\times x\text{ = 8.2}\times\text{ 6} \\ x\text{ = }\frac{8.2\text{ }\times6}{4} \\ \text{ x= 12.3 moles} \end{gathered}[/tex]what is functional group?write the functional group ofalcoholesteracid hydridealdehyde and mention an example of each compound containing these functional group
EXPLANATION:
A functional group is a collection of atoms within molecules that bind together to react in predictable ways.
The functional group tell us how a compound react and, also, the chemical properties of such compound
Below are the functional group of some compound
Alcohol
The functional group of alcohol is ---- OH
Example: Ethanol
Ester
The functional group of Ester is --O--
Example: Ethyl ethanoate
Aldehyde
The functional group of aldehyde is
Example: Vanillin
An equilibrium mixture, at 529°C in a 1208-mL container, involving the chemical system
N2(g) + 3H2(g) == 2NH3(g)
is found to contain 3.62 g of N2, 0.773 g of H2, and 0.498 g of NH3. Calculate the equilibrium constant (Keq expressed in terms of the molar concentrations) at the given temperature.
The equilibrium constant at the given temperature is equal to 0.1677.
What is the equilibrium of a chemical reaction?The chemical equilibrium can be described as the state of a chemical reaction where the concentration of the reactants and products does not change with respect to time.
The balanced chemical equation of the formation of ammonia:
[tex]N_2+3H_2\leftrightarrows 2NH_3[/tex]
The mass of the nitrogen gas = 3.62 grams
The moles of nitrogen gas = 3.62/28 = 0.1293 mol
The concentration of the nitrogen gas = (0.1293/1208)× 1000 = 0.107 M
The mass of the hydrogen gas = 0.773 grams
The moles of hydrogen gas = 3.62/2 = 0.386 mol
The concentration of the hydrogen gas = (0.386/1208)× 1000 = 0.32 M
The mass of the ammonia = 0.498 grams
The moles of ammonia = 0.498/17 = 0.029 mol
The concentration of the ammonia = (0.029/1208)× 1000 = 0.024 M
The equilibrium constant: [tex]K_{eq} = \frac{[NH_3]^2}{[H_2]^3[N_2]}[/tex]
[tex]K_{eq} = \frac{[0.024]^2}{[0.107][0.32]^3}[/tex]
[tex]K_{eq} =0.1677[/tex]
Learn more about the equilibrium of a chemical reaction, here:
brainly.com/question/
#SPJ1
Which of the following can be calculated from the mass of the reactants used in a chemical reaction?Amount of limiting reactant used in a reactionActual yield of productsAmount of excess reactant from a reactionTheoretical yield of products
Explanation:
There are some options that are correct.
1) Amount of limiting reactant used in a reaction.
It can be calculated from the quantity of the reactants.
------
2) Amount of excess reactant from a reaction
It can be also calculated from the quantity of the reactants.
------
3) Theoretical yield of products
Answer:
Amount of limiting reactant used in a reaction
Amount of excess reactant from a reaction
Theoretical yield of products
What is the density of NH3 at 800 torr and 25 degree celsius?
To solve this question, we need to use the following formula:
[tex]\rho\text{ = }\frac{(MM_{NH_3})(P)}{(R)(T)}[/tex]where:
d = density
MMNH3 = molar mass of NH3 = 17 g/mol
P = pressure = 800 Torr = 1.05263 atm (just divide by 760)
T = 25 °C = 273.15 + 25 = 298.15 K
R = 0.082 atm
So:
d = 17 * 1.05263/0.082 * 298.15
d = 17.8947/24.4483
d = 0.7319 g/L
Answer: density = 0.7319 g/L
According the phase diagram for H₂0, what happens to the phaseswater at 0.5 atm pressure as the temperature is decreased from 110°C to -10°C?Pressure (atm)1-0.5-0.25--10Ice(solid)0.01Water(liquid)Water vapor(gas)100Temperature (°C)
Answer:
A. Water changes from a gas to a liquid to a solid.
Explanation:
We can see the following points in the diagram:
- Point A: water starts at 0.5 atm and 100°C, so it is vapor (gas).
- Point B: water changes from vapor to liquid.
- Point C: water changes from liquid to solid.
- Point D: water as a solid reaches a temperature of -10°C.
So, water changes from a gas to a liquid to a solid.
9. You have 500 grams of Cu2S. How many particles are present?
Explanation:
Before we find the number of particles, we have to find the number of moles that are present in 500 g of Cu₂S using the molar mass of it.
molar mass of Cu = 63.55 g/mol
molar mass of S = 32.07 g/mol
molar mass of Cu₂S = 2 * 63.55 g/mol + 1 * 32.07 g/mol
molar mass of Cu₂S = 159.17 g/mol
mass of Cu₂S = 500 g
moles of Cu₂S = 500 g/(159.17 g/mol)
moles of Cu₂S = 3.14 moles
According to Avogadro's Number there are 6.022 *10^23 particles in 1 mol of Cu₂S. Let's use that relationship to find the answer to our problem.
1 mol of Cu₂S = 6.022 * 10^23 particles
number of particles = 3.14 moles * 6.022 *10^23 particles/mol
number of particles = 1.89 *10^24 particles
Answer: There are 1.89 *10^24 particles in 500 g of Cu₂S.