Answer:
[tex]17[/tex]Explanation:
Here, we want to get the effective charge felt by the unknown element
Since the element has a total of 165 protons, the number of electrons in its neutral state is 165 also
Now, having a charge of +2 means it has lost 2 of its electrons, bringing the current total value of electrons to 163
Since there are a total of 163 electrons in the charged state and 15 valence electrons, the number of shielded electrons will be:
[tex]163-15\text{ = 148}[/tex]The effective charge is the difference between the number of protons and the shielding electrons (the electrons not in the valence shell)
Mathematically, we have that as:
[tex]165\text{ - 148 = 17}[/tex]The graph below shows the decay of a radioactive substance over time. What is the half-life of this radioactive substance? Explain your reasoning. Be sure to include the definition of half life in your explanation.
Step 1 - Defining Half-Life
In radioactive decay, as well as in other physical or chemical processes, half-life is defined as the time it takes for an initial amount to decrease in half.
If, for example, we have a sample of Uranium, a radioactive material, of 100g, we could measure the time it takes to decrease to 50g by radioactive decay. This would be Uranium half-life. The half-life is constant for each given substance. Therefore, for the Uranium to decrease from 50g to 25g it would be necessary exactly the same amount of time as to decrease from 100g to 50g.
Step 2 - Interpreting the graph
Since we know that the half-life is the amount of time that is necessary for the initial sample to decrease in half, we can look in the graphic for the time when 100% of the substance becomes 50%.
We can see that, after 1 year (horizontal axis), the radioactive remaning is 50¨% (vertical axis), i.e., exactly a half of the initial amount. The half-life of this substance will be thus 1 year.
What happened to the number of moles in a sample that originally occupied 550 mL with 3.00 moles and then occupied 845 mL?
4.60moles
Explanations:The number of moles and volume are related to each other by the formula;
[tex]\frac{n_1}{v_1}=\frac{n_2}{v_2}=k[/tex]where
n1 and n2 are the initial and final number of moles respectively
v1 and v2 are the initial and final volumes respectively
Given the following parameters
• n1 = 3.00moles
,• v1 = 550mL = 0.55L
,• v2 = 845mL = 0.845L
Required
Final mole "n2"
Substitute the given parameters into the formula
[tex]\begin{gathered} n_2=\frac{n_1v_2}{v_1} \\ n_2=\frac{3\times0.845}{0.55} \\ n_2=\frac{2.535}{0.55} \\ n_2=4.60moles \end{gathered}[/tex]Hence the number of moles will increase to 4.60moles
Constants for waterHvap40.65 kJ/mol-285.83 kJ/mol6.03 kJ/mol4.186 J/g°CAHAHfusionspecific heatmolar mass 18.02 gHow much energy is consumed by thawing 4.3 g ice?
INFORMATION:
Is given that
And we must find how much energy is consumed by thawing 4.3 g ice
STEP BY STEP EXPLANATION:
To find it, we need to multiply the mass of the ice by the Hfusion
[tex]4.3g\times6.03\frac{kJ}{mol}[/tex]Since we need the energy, the answer must be in kJ. So, we need to use the molar mass to obtain the answer in kJ
[tex]4.3g\times\frac{1mol}{18.02g}\times6.03\frac{kJ}{mol}[/tex]Finally, when we simplify the expression, the answer will be in kJ
ANSWER:
A. 4.3 g x 1 mol/18.02 g x 6.03 kJ/mol
determine formula weight for titanic hypochlorite
To determine formula weight of a molecule we will need to atomic mass of each element and sum them all to form the molar mass:
TiClO4 is the formula for titanic hypochlorite, therefore we have:
Ti = 47.86 grams
ClO^- = 51.45 grams
4 ClO^- = 205.8 grams
Now adding all the mass in the formula we will end up with:
TiClO4 = 253.66 g/mol
A gas sample has 0.49 moles and occupies 1.20 L. How many moles of gas are added to increase the volume to 4.30 L?
1.76moles
Explanations:The number of moles of gas "n" is directly proportional to its volume "v". This can be expressed as:
[tex]\begin{gathered} n\alpha v \\ n=kv \\ k=\frac{n_1}{v_1}=\frac{n_2}{v_2} \end{gathered}[/tex]where:
n1 and n2 are initial and final moles respectively
v1 and v2 are the initial and final volumes
Given the following parameters
[tex]\begin{gathered} n_1=0.49mole \\ v_1=1.20L \\ v_2=4.30L \end{gathered}[/tex]Required
Final number of moles "n2"
Substitute the given parameters into the formula
[tex]\begin{gathered} n_2=\frac{n_1v_2}{v_1} \\ n_2=\frac{0.49\times4.30}{1.20} \\ n_2=\frac{2.107}{1.20} \\ n_2=1.76moles \end{gathered}[/tex]Hence the moles of gas added to increase the volume to 4.30L is 1.76moles
Complete the third row of the table.Express the temperature in degrees Celsius to three significant figures.
Answer:
[tex]T_2\text{ = 17.3}\degree C[/tex]Explanation:
Here, we want to get the initial temperature
From Charles' law, we know that at constant pressure, the volume of a given mass of gas is directly proportional to its temperature
Mathematically, we can have this written as:
[tex]\frac{V_1}{T_1\text{ }}=\frac{V_2}{T_2}[/tex]We can rewrite the formula in terms of the missing value as follows:
[tex]T_2\text{ = }\frac{V_2T_1}{V_1}[/tex]Let us write out the values given, not forgetting that we have to convert the temperature value to Kelvin by adding 273.15 K
Thus, we have:
[tex]\begin{gathered} V_1\text{ = 2.21 L} \\ T_1\text{ = 14.7 + 273.15 = 287.85 K} \\ V_2\text{ = 2.23 L} \\ T_2\text{ = ?} \end{gathered}[/tex]Substituting these values in the re-written formula, we have it as:
[tex]T_2=\text{ }\frac{2.23\times287.85}{2.21}\text{ = 290.455 K}[/tex]Finally, what we have to do is to convert this temperature to degrees celsius by subtracting 273.15 K
We have this as:
[tex]290.455\text{ - 273.15 = 17.3 }[/tex]The equation below to answer the question and the list below. In the list below select all the products shown in the equation above.
Answer
O₂
C₆H₁₂O₆
Explanation
Given equation:
[tex]6H_2O+6CO_2\rightarrow C_6H_{12}O_6+6O_2[/tex]From the balanced equation above, the products are the species after the arrow.
So, ALL the products shown in the equation above are:
O₂ and C₆H₁₂O₆
Is cellobiose Polar or non-polar
Cellobiose is a complex carbohydrate which consists of two molecules of glucose that are combined by a β–(1,4′) glycosidic bond.
Cellobiose is a polar compound just like every other carbohydrate.
Polar compound are those compounds that usually have an end with a positive charge and another with a negative charge.
When cellobiose just like every other glucose is dissolve in water or any other polar solvent, it completely dissolves in the solution. Examples of polar solvents are ethanol, water etc.
Cellobiose is a polar compound just like it's parent compound glucose.
the electronegativity of the halogens changes down group 7.Explain how electronegativity changes down group 7. (3 marks)
STEP-BY-STEP EXPLANATION:
Firstly, we need to define electronegativity
Electronegativity is defined as the tendency of an atom in a covalent bond to attract the bonding electrons.
The electronegativity of the halogen decreases down the group due to an increase in the radius of the atom resulting in the addition of outermost shells to the shell of the atom. As the number of shells increases, the force attraction between the nucleus and the electron moving around the shell decreases.
Show how by calculation how you will prepare 1.0x10-2 M NaOH from 0.1 M NaoHstock solution
To prepare 1.0x10^-2M NaOH from 0.1M NaOH stock solution, you have to take a volume of the stock solution and dilute it using 9 times that volume of water. We conclude it from the equation for dilutions:
[tex]\begin{gathered} V1C1=V2C2 \\ 0.1V1=0.01V2 \\ \frac{0.1}{0.01}V1=V2 \\ 10V1=V2 \\ V1=\frac{1}{10}V2 \end{gathered}[/tex]It means that to prepare the 1.0x10^-2 solution, dilute 1 mL (for instance) of stock solution in 9mL of water.
A chemist prepares a sample of hydrogen bro-mide and finds that it occupies 238 mL at 66°C and 513 Torr.What volume would it occupy at O°C at the same pressure?Answer in units of mL.
Answer:
[tex]191.68\text{ mL}[/tex]Explanation:
Here, we want to get the final volume
From the general gas equation, we have it that:
[tex]\frac{P_1V_1}{T_1}\text{ = }\frac{P_2V_2}{T_2}[/tex]From the question, we have it that:
P1 is the initial pressure which is 513 torr
V1 is the initial volume which is 238 mL
T1 is the initial temperature which we have to convert to absolute value by adding 273.15 K ( 66 + 273.15 = 339.15 K)
P2 is the final pressure that is the same as the initial which is 513 torr
V2 is the final volume that we want to calculate
T2 is the final temperature which is 273.15 K (0 degrees Celsius is 273.15 K)
Substituting the values, we have:
[tex]\begin{gathered} \frac{513\times238}{339.15}\text{ = }\frac{513\times V_2}{273.15} \\ \\ V_2\text{ = }\frac{513\times238\times273.15}{339.15\text{ }\times\text{ 513}}\text{ = 191.68 mL} \end{gathered}[/tex]We could have solved this by using Charles' law that relates temperature to volume (volume is directly proportional to temperature)
Why are solids not included in the Ksp formula?
Explanation:
When calculating the equilibrium constant expression we don't include pure solids or liquids because their concentrations stay constant during the reaction. Since their concentrations don't change significantly throughout the reaction (if enough is present) they don't affect the equilibrium so we don't include them in the ksp formula.
Answer: because the concentration of a purid solid remains constant during the reaction.
Calculate the number of formula units of KBr in 16.4 moles6.643.67x10229.87x10241786
The formula units corresponds to the molecules of a substance, there is a relationship between moles and molecules, this relationship is Avogadro's number.
Avogadro's number tells us that a mole of any substance contains 6.022x10^23 molecules. Therefore in 16.4 moles of Kbr there will be:
[tex]\begin{gathered} \text{Formula units}=\text{Given moles}\times\frac{6.022\times10^{23}molecules}{1\text{ mol}} \\ \text{Formula units}=16.4\text{mol}\times\frac{6.022\times10^{23}molecules}{1\text{ mol}}=9.87\times10^{24}formulaunits \end{gathered}[/tex]The number of formula units of Kbr in 16.4 moles is 9.87x10^24
Describe a real-world example that demonstrates this relationship. In your description identify the two variables (volume and pressure) and describe how one changes as the other is increased or decreased.
Answer:
Explanation:
Here, we want to describe a relationship
Let us look at a football pump. It is used to manually pump air into the football
When we press the piston,air is released. When we leave it, no air is coming out
When unpressed, we have the maximum volume in the pump. But as we press the pump (this is us applying pressure) , air is let out into the ball. This means volume of air is being transferred from the pump into the ball
Thus, at minimum pressure, we have maximum volume (no air is let out of the pump)
At maximum pressure (when we press the pump down to its end), we have no volume left in the pump (minimum volume)
That shows there is an inverse relationship between volume and pressure
As pressure increases, volume decreases. And as pressure decreases, volume increases
1. If the reaction of 80 grams of Pb(NO3)2 produces 21.3 grams of NO2, what is thepercent yield?2Pb(NO3)22PbO + 4NO₂ + 02
ANSWER
The percentage yield of the reaction is 95.7%
EXPLANATION
Given that;
The mass of Pb(NO3)2 is 80 grams
The mass of NO2 produced is 21.3 grams
Follow the steps below to find the percentage yield of the reaction
Step 1; Write a balanced equation of the reaction
[tex]\text{ 2Pb\lparen NO}_3)_2\text{ }\rightarrow\text{ 2PbO + 4NO}_2\text{ + O}_2[/tex]Step 2; Find the number of moles of Pb(NO3)2 using the formula below
[tex]\text{ mole = }\frac{\text{ mass}}{\text{ molar mass}}[/tex]Recall, that the molar mass of Pb(NO3)2 is 331.2 g/mol
[tex]\begin{gathered} \text{mole = }\frac{\text{ 80}}{\text{ 331.2}} \\ \text{ mole = 0.242 mol} \end{gathered}[/tex]Step 3; Find the number of moles of NO2 using a stoichiometry ratio
In the equation above, 2 moles Pb(NO3)2 give 4 moles NO2
Let x represents the number of moles of NO2
[tex]\begin{gathered} \text{ 2 moles Pb\lparen NO}_3)_2\text{ }\rightarrow\text{ 4 moles NO}_2 \\ \text{ 0.242 mol Pb\lparen NO}_3)_2\text{ }\rightarrow\text{ x moles NO}_2 \\ \text{ cross multiply} \\ \text{ 2 moles Pb\lparen NO}_3)_2\times\text{ x moles NO}_2\text{ = 4 moles NO}_2\text{ }\times\text{ 0.242 mol Pb\lparen NO}_3)_2 \\ \text{ Isolate x} \\ \text{ x moles NO}_2\text{ = }\frac{4\text{ moles NO}_{2\text{ }}\times0.242mol\cancel{Pb(NO_3})_2}{2moles\cancel{Pb(NO_3})_2} \\ \text{ } \\ \text{ x moles NO}_2\text{ = }\frac{4\text{ }\times\text{ 0.242}}{2\text{ }} \\ \text{ } \\ \text{ x moles NO}_2\text{ = }\frac{0.968}{2} \\ \text{ x moles NO}_2\text{ = 0.484 mole} \end{gathered}[/tex]The number of moles of NO2 is 0.484 mole
Step 4; Find the mass of NO2
[tex]\text{ Mole = }\frac{\text{ mass}}{\text{ molar mass}}[/tex]Recall, that the molar mass of NO2 is 46 g/mol
[tex]\begin{gathered} \text{ mass = mole }\times\text{ molar mass} \\ \text{ mass = 0.484 }\times\text{ 46} \\ \text{ mass = 22.264 grams} \end{gathered}[/tex]Since the calculated mass of NO2 is 22.264 grams, hence, the theoretical yield is 22.264 grams
Step 5; Find the percentage yield of NO2
[tex]\text{ Percentage yield = }\frac{\text{ Actual yield }}{\text{ theoretical yield}}\times\text{ 100\%}[/tex][tex]\begin{gathered} \text{ Percentage yield = }\frac{\text{ 21.3}}{\text{ 22.264}}\text{ }\times\text{ 100} \\ \\ \text{ Percentage yield = 0.956 }\times\text{ 100} \\ \text{ Percentage yield = 95.7\%} \end{gathered}[/tex]Therefore, the percentage yield of the reaction is 95.7%
How do water molecules change as their state of matter changes from solid, to liquid, to gas?
So,
Let me upload an image that represents the situation first:
As you can see, the water molecules change a solid into a liquid or gas by changing its temperature. This is known as changing its state. Water is a liquid at room temperature, but becomes a solid (called ice) if it is cooled down. The same water turns into a gas (called water vapor) if it is heated up.
The water molecules are too close between each other when they form a solid. They are a little bit separated when they form the liquid state, and they are completely scattered when they form a gas.
And Ion in the second column of the periodic table has 20 protons. how many electrons does it have?
In the second column of the periodic table we find the following elements: Be, Mg, Ca, Sr, Ba Ra. To identify which element you are referring to we must look up its atomic number.
The atomic number corresponds to the number of protons, so we will look for an element whose atomic number is equal to 20.
It corresponds to the element calcium, which has an oxidation state equal to +2, that is to say, that its ion must lose 2 electrons to have a positive charge equal to 2.
As a neutral atom has an equal number of protons and neutrons, the neutral atom of Ca will have 20 electrons and the Ca+2 ion will have two fewer electrons, that is to say, 18 electrons.
The ion has 18 electrons
Which of the following is a property of bases?OA. They are found in fruit.OB. They are slippery.OC. They pollute the air.OD. They taste sour.
According to what is known about bases, the correct answer to this question is B. They are slippery.
Use the activity series below to predict the products of each of the following reactions. You do not need tobalance the equations.Li > K > Ba> Sr > Ca> Na > Mg > Al> Mn > Zn > Cr > Fe > Cd>Co> Ni> Sn> Pb > H> Sb> Bi > Cu > Ag > Pd > Hg > Pt > AuF2 > Cl₂> Br2 > 12FeSO4 + Na - ?CCl4 + Br₂ ?1Ono reactionno reactionNa₂SO4 + FeBrCl + CO FeNa+ SO4CB4 + Cl₂DONECOMPLETE
Answer:
[tex]B[/tex]Explanation:
Using the activity series, we want to predict the products of the reaction
From the series, we know that sodium is higher than iron. This means that sodium can displace iron from its salt
Thus, we have the equation of reaction as:
[tex]FeSO_4\text{ + 2Na }\rightarrow\text{ Na}_2SO_4\text{ + Fe}[/tex]A hydrocarbon that contains a C to C double bond is:Group of answer choicesSaturatedUnsaturatedAlkaneAlcohol
Answer: the best option to answer the question is the second one (letter B).
Explanation:
The question requires us to choose, among the options given, which one best describes a hydrocarbon that contains a C to C double bond.
We can give the following definitions to the options provided by the question:
- Saturated: a saturated hydrocarbon presents all C to C bonds as single bonds;
- Unsaturated: an unsaturated hydrocarbon presents at least one C to C double (or triple) bond;
- Alkane: an alkane can be defined as an open chain hydrocarbon that contains only single C to C bonds;
- Alcohol: in chemistry, an alcohol is defined as a moelcule that contains at least one hydroxyl (-OH) attatched to a carbon atom of a hydrocarbon chain.
Considering the definitions above, we can say that an unsaturated hydrocarbon best describes a hydrocarbon that contains a C to C double bond. Therefore, the best option to answer the question is the second one (letter B).
How many and what types of bonds are shown here? I know some, but not all. I need to know so I can calculate the enthalpy change.
Here in all the compounds we see covalent bonds, that is to say that the atoms are sharing electrons with each other. Now, covalent bonds are divided into single, double or triple according to the number of electrons they share.
When they share a pair of electrons, a line is drawn that represents a bond. If it has only one it will be a simple bond, if it has two it will be a double bond and if it has 3 it will be a triple bond.
Here we see simple covalent bonds and double covalent bonds.
Now, to calculate the enthalpy change we can do it starting from the bond energies, applying the following formula:
[tex]\Delta H_r=PotentialEnergyofProductBonds-PotentialEnergyofReactantBonds[/tex]The bonds to take into account for the calculation of enthalpy will be:
Ethanol:
5 bonds C-H
1 bond C-O
1 bond O-H
Oxygen:
1 bond O=O, but there are 3 moles of O2, so it will be 3 bonds O=O
Carbon dioxide:
2 bonds O=C, there are 2 moles of CO2, so it will be 2x2= 4 bonds O=C
Water:
2 bonds O-H, there are 3 moles of H2O, so it will be 2x3=6 bonds O-H
Which process is not reversible?a) melting waxb) extracting iron metal from iron (lll) oxidec) burning butane in a candle light d) dissolving sugar .. I know it’s either b or c just need clarification.
The correct answer is c) burning butane in a candle light.
All the other processes are reversible because the products can transform again in the reactants. But combustion reactions are different, they are not reversible.
The reaction that takes place is:
[tex][/tex]If the hydrogen ion concentration [H*] is 1.00 x 10-10 the solution isacidic basic (alkaline)neutral or none of the above
Answer
basic (alkaline)
Explanation
To know if the solution is acidic, basic or neutral, you need to determine the pH of the solution.
[tex]pH=-log[OH^+][/tex]Putting [OH⁺] = 1.00 x 10⁻¹⁰ into the pH formula, we have
[tex]\begin{gathered} pH=-log(1.00\times10^{-10}) \\ \\ pH=-(-10) \\ \\ pH=10 \end{gathered}[/tex]Note that the pH scale ranges from 0 to 14, with 7 being neutral. pHs less than 7 are acidic while pHs greater than 7 are alkaline (basic).
Therefore, the solution is basic (alkaline)
How are antibiotics made in chemistry
Antibiotics are drugs that fight infections caused by bacteria in humans and animals.
Antibiotics can be produced from natural means from microorganisms, microorganism can produce substances that inhibit the action of bacteria, as does penicillin.
There are other kinds of antibiotics made in a laboratory, those are called "semi-synthetic". These antibiotics are extracted from microbes and then enhanced in the laboratory by chemical modification.
It’s finding the reaction. It needs to be completed and balanced
answer
balanced equation
Fe(s) + Na₃PO ₄ -> FePO₄ + 3Na
In each of the following elements:-Assign oxidation numbers.-Identify the oxidizing and reducing agents.-Identify the change in oxidation number. Cr2O7^2- + 2OH^- —> 2CrO4^2- + H2O
To dicover which compound is being oxidized and which one is being reduced, we need to know the oxidation number of each specie.
The oxidation number (NOX) of an element is the electrical charge it acquires when it forms an ionic bond or the partial character (δ) it acquires when it forms a predominantly covalent bond.
There are some rules for NOX, like:
The NOX of simple substances is always zero.
The NOX of ions is equal to their charge.
The sum of the NOX elements of a compound always equals zero.
The sum of the NOXs of the elements in a composite ion is always equal to the charge on the ion.
The NOX of Oxygen in an compound is -2 almost in all cases.
The NOX of hydrogen is +1
With this in mind, let's calculate the NOX of each specie of the following equation:
Cr2O7^2- + 2OH^- —> 2CrO4^2- + H2O
Reactants:
Cr2O7^2-
NOX of oxygen: -2
NOX of Cr: +6
2x + (-2*7) = -2
2x = 14 - 2
x = 6
OH-:
O: -2
H: +1
Products
CrO4^2-
Nox of oxygen: -2
Nox of Cr: +8
x + (-2*4) = -2
x - 8 = -2
x = +6
H2O
H: +1
O: -2
Answer:
-Assign oxidation numbers:
Products: Cr: +6; O: -2; H: +1
Reactants: Cr: +6; O: -2; H: +1
-Identify the oxidizing and reducing agents:
No compounds oxidize or reduce. This reaction is not a redox reaction.
-Identify the change in oxidation number: there is no change in oxidation number, so this is not a redox reaction.
1. If 22.5L of nitrogen at 745 mm Hg are compressed to 725 minHg. What is the new volume?od SestD001 20v bu par 1.0
Step 1 - Understanding how pressure and volume are related
There are three main variables that can modify the state of a gas: pressure, volume and temperature.
When one of these variables is kept constant, the remaining two become proportional to each other. Suppose temperature is kept constant. In this case, pressure and volume become proportional.
I.e., if we increase the pressure, we also increase the volume. We can state it mathematically as follows:
[tex]p_1V_1=p_2V_2[/tex]We can use this equation to solve this exercise.
Step 2 - Calculating the new volume
According to the exercise:
[tex]\begin{gathered} V_1=22.5L \\ \\ p_1=745mmHg \\ \\ p_2=725mmHg \\ \\ V_2=? \end{gathered}[/tex]Setting these values in the equation given in step 1:
[tex]\begin{gathered} 22.5\times745=725\times V_2 \\ \\ V_2=\frac{22.5\times745}{725}=23.1L \end{gathered}[/tex]Answer: 23.1L
Which option is an example of energy transfer via radiation
Answer
Sunlight warming a concrete sidewalk.
Explanation
The transfer of thermal energy through air molecules is known as radiation.
It is as opposed to conduction (transfer through solids) and convection (transfer through liquid).
When sunlight warms a concrete sidewalk, thermal energy from the sun travels through the air to reach the sidewalk.
The option that best describes energy transfer via radiation would be sunlight warming a concrete sidewalk.
what is the initial volume, in milliliters, needed to prepare each of the following diluted solution?350 mL of 3.0 %(m/v) HCl from 15.0 % (m/v) HCl Express your answer to two significant figures and include the appropriate units.
ANSWER
The initial volume of the solution is 70mL
EXPLANATION
Given that;
The initial concentration of the solution is 15.0% m/v
The final volume of the solution is 350mL
The final concentration of the solution is 3.0% m/v
Follow the steps below to find the initial volume of the solution.
Step 1; Apply the dilution formula
[tex]\text{ C1 V1 = C2 V2}[/tex]Substitute the given data into the above formula
[tex]\begin{gathered} \text{ }\frac{15}{100}\text{ }\times\text{ V1 = }\frac{3}{100}\times\text{ 350} \\ \text{ 0.15 }\times\text{ V1 = 0.03 }\times\text{ 350} \\ \text{ 0.15 V1 = 10.5} \\ \text{ Divide both sides by 0.15} \\ \text{ V1 = }\frac{\text{ 10.5}}{\text{ 0.15}} \\ \text{ V1 = 70mL} \end{gathered}[/tex]Therefore, the initial volume of the solution is 70mL
What is the name of compound P4S7
INFORMATION:
We have the next compound
[tex]P_4S_7[/tex]And we must name it.
STEP BY STEP EXPLANATION:
To name binary (two-element) molecular compounds, we need to know the following information:
The first element in the formula is simply listed using the name of the element. The second element is named by taking the stem of the element name and adding the suffix -ide.
We can use the following table to specify the number of atoms in a molecule
In our case,
the first element is P: Phosphorus and it has 4 atoms, so the first word for the name of the compound would be tetraphosphorus.
The second element is S: sulfur and it has 7 atoms, so the second word for the name of the compound adding the suffix would be heptasulphide.
Finally, the name would be tetraphosphorus heptasulphide.
ANSWER:
The name of compound P4S7 is tetraphosphorus heptasulphide