Answer
19.6 grams
Explanation
Given:
Mass of calcium phosphate produced = 50.500 g
Equation: 3Ca(s) + 2H3PO4(aq) ---> Ca3(PO4)2(s) + 3H2(g)
What to find:
The grams of calcium required to produce 50.500 g of calcium phosphate.
Step-by-step solution:
From the equation, 3 mol Ca produce 1 mol Ca3(PO4)2
1 mole Ca3(PO4)2 = 310.19 grams
1 mole Ca = 40.078 grams
This means, (3 x 40.078 g) = 120.234 g Ca produce 310.19 g Ca3(PO4)2
So x grams Ca will be required to produce 50.500 grams Ca3(PO4)2
x grams Ca will be equal
[tex]\frac{50.500\text{ }g}{310.19\text{ }g}\times120.234g\text{ }Ca=19.6\text{ }grams\text{ }Ca[/tex]The grams of calcium required to produce 50.500 g of calcium phosphate = 19.6 grams
A legend is a traditional story that explains something in real life. Sometimes they are accepted as true, but sometimes they are fantastical and just plain fun. There are many legends that surround the North Star explaining its creation as well as why it is stationary.
Take some time to research some of the legends of the North Star. After you have had a chance to read several of them, create your own fantastical story of the North Star. It can be how it came to be or explain why it is stationary.
There are many legends of the North Star that have been told over the years by different civilizations and of them is a mythical story told about the existence of the star.
What is a Legend of the North Star?It is said that it is a little dot left behind after God created the stars and based on the fact that the dot was not like the other stars as it was almost an afterthought and then it came to the attention of Luminaria who granted the dot its wish and it became a real star like the others and became the Star of Bethlehem.
Hence, it can be seen that the given legend and mythical stories are just one of the many ways humans try to understand the phenomena of astrology and how they attach certain significance to it.
With this in mind, it is very clear to see that the North Star is a special star.
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The
following reaction: Na+ (g) --> Na+ (aq) AH = -364 kJmol
1 is endothermic reaction.
True
False
Na+ (g) --> Na+ (aq) AH = -364 kJmol 1 is endothermic reaction. The given reaction is False, As H is negative hence exothermic reaction not endothermic
What is endothermic reaction?
Chemical processes referred to as endothermic reactions occur when the reactants take in heat energy from their environment to create products. These reactions produce a cooling effect by bringing the temperature of the space around them down. Ice cubes absorb heat energy from their surroundings and melt to generate liquid water as an example of an endothermic physical process (no chemical bonds are broken or formed).
False, As H is negative hence exothermic reaction not endothermic
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The chemical equation for the combustion of ethanol is as follows:C2HyOH + 302 - 2002 + 3H20
5998kJ
Explanations:Given the reaction between ethanol and oxygen expressed as:
[tex]C_2H_5OH+3O_2\rightarrow2CO_2+3H_2O[/tex]For the product
We have 2 moles of CO2 and 3 moles of water. The total bond energy in the product is expressed as:
[tex]\begin{gathered} \triangle H_p=2(2C=O)+3(2O-H) \\ \triangle H_p=4(799)+6(467) \\ \triangle H_p=3196+2802 \\ \triangle H_p=5998kJ \end{gathered}[/tex]Hence the total energy transferred to build all the bond energy in the product is 5998kJ
Explain the difference between a cation and an anion. Give hints for remembering each.
Some atoms are neutral and others have positive or negative charges.
The charged atoms are called "ions".
- If the ion has positive charge, it is called cation.
- If the ion has negative charge, it is called anion.
Ions can be identified by their charge, for example:
- Cations: Na^+1, K^+1, Mg^+2
- Anions: Cl^-1, Br^-1
what percent of a sample of As-81 remains un decayed after 43.2 seconds
The percentage of the sample of As-81 remaining undecayed after 43.2 seconds is 40.6%
How to determine the percentage remaining undecayedWe'll beging by calculating the number of half lives that has elapsed. This can be obtained as follow
The following data were obtained from the question:
Time (t) = 43.2 secondsHalf-life (t½) of As-81 = 33 secondsNumber of half-lives (n) =?n = t / t½
n = 43.2 / 33
n = 1.3
Finally, we shall determine the percentage remaining undecayed. This is shown below:
Original percentage (N₀) = 100%Number of half-lives (n) = 1.3Percentage remaining (N) = ?N = N₀ / 2ⁿ
N = 100 / 2^1.3
N = 40.6%
Thus, we can conclude that the percenatge undecayed is 40.6%
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Calculate the boiling point of a 0.33 m solution of a solute in benzene.
(Kb = 2.53°C /m).
The boiling point of the solution is 80.93°C.
What is the boiling point?We know that the boiling point has to do with the temperature at which the pressure inside the system is the same as the atmospheric pressure. Now we know that the boiling point of the pure benzene is 80.1 °C.
Also;
ΔT = K m i
ΔT = boiling point elevation
K = boiling point constant
m = molality
i = Van Hoff factor
ΔT = 2.53°C /m * 0.33 m * 1
ΔT = 0.83°C
Boiling point of the solution = 0.83°C + 80.1 °C
= 80.93°C
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What is the empirical formula for sulfur dioxide?A. SDO B. SD C. S2O2 D. SO2
Explanation:
We have to find the empirical formula for sulfur dioxide. The compound contains two elements: Sulfur and oxygen.
As it name says, it is a dioxide, it means that one molecule of the compound contains two atoms of O.
The empirical formula of sulfur dioxide is: SO₂.
Answer: d. SO₂.
An unknown metal with a charge of 4 combines with oxygen. How many oxygen ionsare needed in a neutral compound of this metal and oxygen?
2 oxygen ions
ExplanationOxygen is a non-metal with an atomic number of 8. The electronic configuraton of the element is given as:
[tex]O;\text{ }1s^22s^22p^^4[/tex]If a an unknown metal with a charge of 4 combines with oxygen, the required reaction will be:
[tex]M^{4+}+O^{2-}\rightarrow MO_2[/tex]Since oxygen is in group VI of the periodic table and has a oxidation number of -2, to form a neutral compound with charge of +4, this means that 2 oxygen ion will combine with the metal to form a neural compound MO2
In the reaction below, if a total of 10.0 g of zinc and hydrochloric acid react completely, what is the total mass of zinc chloride and hydrogen produced?Zn(s) + 2HCl(aq) to ZnCl2(aq) + H2(g)Exactly 10.0 gLess than 10.0 gNot enough information to tellGreater than 10.0 g
Answer:
Not enough information to tell.
Explanation:
What is given?
Mass of Zn = 10.0 g,
Mass of HCl = 10.0 g,
Molar mass of Zn = 65.4 g/mol,
Molar mass of HCl = 36.4 g/mol,
Molar mass of ZnCl2 = 136.2 g/mol,
Molar mass of H2 = 2 g/mol.
Step-by-step solution:
First, let's convert 10.0 g of each reactant to moles using their respective molar mass:
[tex]\begin{gathered} 10.0\text{ g Zn}\cdot\frac{1\text{ mol Zn}}{65.4\text{ g Zn}}=0.153\text{ moles Zn,} \\ \\ 10.0\text{ g HCl}\cdot\frac{1\text{ mol HCl}}{36.4\text{ g HCl}}=0.275\text{ moles HCl.} \end{gathered}[/tex]Now, let's identify what is the limiting reactant. Let's see how many moles of ZnCl2 can be produced by 0.153 moles of Zn if 1 mol of Zn reacted produces 1 mol of ZnCl2, and how many moles of ZnCl2 can be produced by 0.275 moles of HCl if 2 moles of HCl reacted produces 1 mol of ZnCl2:
[tex]\begin{gathered} 0.153\text{ moles Zn}\cdot\frac{1\text{ mol ZnCl}_2}{1\text{ mol Zn}}=0.153\text{ moles ZnCl}_2, \\ \\ 0.275\text{ moles HCl}\cdot\frac{1\text{ mol ZnCl}_2}{2\text{ moles HCl}}=0.138\text{ moles ZnCl}_2. \end{gathered}[/tex]You can realize that the limiting reactant, in this case, is HCl because is the first reactant consumed first and this reactant 'impose' the limit to produce the products.
So now, let's find how many moles of H2 are being produced by 0.275 moles of HCl if 2 moles of HCl reacted produces 1 mol of H2:
[tex]0.275\text{ moles HCl}\cdot\frac{1\text{ mol H}_2}{2\text{ moles HCl}}=0.138\text{ moles H}_2.[/tex]The final step is to convert each number of moles of each product to grams using their respective molar mass, as follows:
[tex]\begin{gathered} 0.138\text{ moles ZnCl}_2\cdot\frac{136.2\text{ g ZnCl}_2}{1\text{ mol ZnCl}_2}=18.8\text{ g ZnCl}_2, \\ \\ 0.138\text{ moles H}_2\cdot\frac{2\text{ g H}_2}{1\text{ mol H}_2}=0.276\text{ g H}_2. \end{gathered}[/tex]We're producing 18.8 g of zinc chloride (ZnCl2), and 0.276 g of hydrogen (H2), so based on this logic the answer would be not enough information to tell.
If you have 5.3x10^26 molecules of water how many moles of water do you have?
The question requires us to calculate the amount of moles of water that we would have in 5.3x10^26 molecules of water.
To solve this problem, we'll need to consider the Avogadro Number: this number states the amount of particles (electrons, ions, atoms, molecules etc.) in one mole of a substance. The Avogadro Number corresponds to 6.022 x 10^23 particles per mol.
Considering the Avogadro number and the number of molecules provided by the question, we can write:
6.022 x 10^23 molecules of water -------------------- 1 mol of water
5.3 x 10^26 molecules of water ------------------------ x
Solving for x, we'll have:
[tex]x=\frac{(5.3\times10^{26}molecules\text{ of water)}\times(1\text{ mol of water)}}{(6.022\times10^{23}\text{molecules of water)}}=8.8\times10^2mol\text{ of water}[/tex]Therefore, there are 8.8 x 10^2 moles of water in 5.3 x 10^26 molecules of water.
(The question is in the photo Sorry Lol) What volume of chlorine gas at 36.0°C and 1.74 atm is needed to react completely with12.0 g of sodium to form NaCl?Answer in units of L
3.786137931L of chlorine are needed.
1st) It is necessary to write the balanced equation of the reaction between chlorine gas (Cl2) and sodium (Na) to produce sodium chloride (NaCl):
[tex]2Na+Cl_2\text{ }\rightarrow\text{ 2 NaCl}[/tex]Now we know that 1 mol of chlorine gas is needed to react with 2 moles of sodium in the production of sodium chloride. With the molar mass of Na (23.0g/mol) and Cl2 (71.0g/mol), we can see that 71.0g of Cl2 are needed to react with 46.0g of sodium.
2nd) Knowing that 71.0g of Cl2 are needed to react with 46.0g of sodium, we can use a mathematical rule of three to calculate the amount of Cl2 that will react completely with 12.0g of sodium:
[tex]\begin{gathered} 46.0\text{gNa}-71.0gCl_2 \\ 12.0\text{gNa}-x=\frac{12.0\text{gNa}\cdot71.0Cl_2}{46.0\text{gNa}} \\ x=18.5gCl_2 \end{gathered}[/tex]3rd) Now it is necessary to convert the mass of chlorine gas into moles, so we can use it in the Ideal gas formula:
[tex]\begin{gathered} 71.0gCl_2-1mol \\ 18.5gCl_2-x=\frac{18.5gCl_2\cdot1mol}{71.0gCl_2} \\ x=0.26\text{mol} \end{gathered}[/tex]So, 0.26 moles of chlorine gas are needed.
4th) With the formula of Ideal gases and replacing the values of Pressure (P), number of moles (n) and Temperature (T, in Kelvin), we can calculate the volume of Cl2:
[tex]\begin{gathered} P\mathrm{}V=n\mathrm{}R\mathrm{}T \\ 1.74atm.V=0.26mol\cdot0.082\frac{atm\cdot L}{\text{mol}\cdot K}\cdot309K \\ V=\frac{0.26mol\cdot0.082\frac{atm\cdot L}{\text{mol}\cdot K}\cdot309K}{1.74atm} \\ V=3.786137931L \end{gathered}[/tex]Finally, 3.786137931L of chlorine are needed to react completely with 12.0g of sodiu.
When something heat up new energy is created and when something coole dan energy isdestroyer check one)How could you revise this statement to be more complete or correol?
When something heats up energy is absorbed from another system and when something cooler down energy is released to another system.
When a reaction releases heat, it is classified as exothermic. The absorption of heat in a reaction makes it endothermic.
17) Which atom has a higher electronegativity, Be or O?
A NaOH solution contains 26.0 g of NaOH, and it’s concentration is 1.3M. What is its volume?
Answer
Volume = 0.5 L
Explanation
Mass of NaOH = 26.0 g
Molarity = 1.3 M
Molar mass of NaOH = 39.997 g/mol
Volume = ?
The volume of NaoH can be calculated using
[tex]\begin{gathered} V=\frac{n}{M} \\ \text{Where;} \\ V\text{ is the volume} \\ n\text{ is the number of mole of NaOH} \\ \text{M is the Molarity} \end{gathered}[/tex]But the number of mole of NaOH, n = mass of NaOH / Molar mass of NaOH
[tex]\Rightarrow n=\frac{26.0\text{ g}}{39.997\text{ g/mol}}=0.65\text{ mole}[/tex]Therefore, the volume of NaOH is
[tex]V=\frac{0.65}{1.3}=0.50\text{ L}[/tex]Calculate the frequency of light that has a wavelength of 6.2 * 10^-7 m.
Answer:
4.839 × 10^14 Hz or s^-1
Explanation:
speed of light = wavelength times frequency
frequency = speed of light ÷ wavelength
3.00 x 10^8 = speed of light
3.00 x 10^8 m/s ÷ 6.2 x 10^-7 m = 4.839 × 10^14 Hz or s^-1
socraticorg
check alll of the following statements that are true about the ion whose symbol Ca2+
The correct statement about the description of ion whose symbol is Ca2+ among the choices above are:
It is a cationIt is a divalent metalThe options b and d are correct.
How calcium ion is a cation and divalent metalIt follows that elements whose charge on them are positive are called cations. In order words, in the periodic table of science of chemistry, the positively charged ions of elements are known as cations. Calcium has a positive of 2 on as it ion and this makes it a cation.
In addition to the above, calcium ion helps in signal transduction pathways of cells of living organisms. This goes to say that they also help in the body's normal functioning of the human body.
However, on a second note, calcium in the periodic table belongs to group 2, has a valence electrons of 2 and a metallic element; thereby making it a divalent metal.
In conclusion, we can now confirm from all said above that calcium above is a cation.
Complete question:
Check all of the following statements that are true about the ion whose symbol Ca2+
a. It is an anion
b. It is a cation
c. Its atoms is connected by tripple bonds
d. It is a divalent metal
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I need help please because a few tutors I got had false answer and when I tried to do it it was also wrong.
Answer:
Explanations:
a) The balanced chemical reaction for the complete combustion of pentane is expressed as:
[tex]C_5H_{12}+8O_{2(g)}\rightarrow5CO_{2(g)}+6H_2O_{(g)}[/tex]Note that oxygen, carbondioxide and water are all in gaseous state.
What will be the final temperature of a 3L nitrogen gas initially exposed to a temperature of 10°C if the volume is increased to 10L assuming that the pressure is fixed at 1 atm?
Step 1
Charles's law states that the volume (V) of a gas is directly proportional to its absolute temperature. It is assumed that the pressure and the quantity of gas remain constant.
Mathematically:
[tex]\frac{V1}{T1}=\frac{V2}{T2}[/tex]-------------------
Step 2
Information provided:
T1 = 10 °C + 273 = 283 K
V1 = 3 L
---
T2 = Unknown
V2 = 10 L
-------------------
Step 3
Procedure:
[tex]\begin{gathered} \frac{V1}{T1}=\frac{V2}{T2} \\ T2\text{ =}\frac{V2}{V1}\text{ x T1} \\ T2\text{ = }\frac{10\text{ L}}{3\text{ L}}\text{ }x\text{ }283\text{ K } \\ T2\text{ = 943 K} \end{gathered}[/tex]Answer: 943 K or 670 °C
In what direction will the reaction proceed ? Explanation please
In order to calculate this question, we will use the reaction quotient Q, which has a very similar formula as the equilibrium formula, but this Q can be calculated not just in equilibrium (where Q = K) but in any part of the reaction, so K is the equilibrium, and Q is what is used to see where the reaction will shift towards until it reaches equilibrium, we can have three possible outcomes:
Q = K, the reaction is already in equilibrium
Q > K, the reaction will proceed in the reverse direction
Q < K, the reaction will proceed in the forward direction
Let's set up the formula:
Q = [products]/[reactants], the brackets mean Concentration of each compound. Now adding our compounds
Q = [BrCl]^2/[Br2]*[Cl2], the BrCl is raised to 2 because we have 2 BrCl in the reaction, this is a rule for the equilibrium formula, we use the coefficient in front of the compound and raise its concentration to this number
Now we need the concentration of each compound, to find it we will use the Molarity formula
M = n/V
M = 0.15/2
M = 0.075M, notice that since we have the same number of moles and volume for every compound, we will have the same concentration for every compound, going back to our formula
Q = [0.075]^2/[0.075][0.075]
Q = 1.0
Since K = 7.0 and Q = 1.0
K > Q, the reaction will proceed in the forward direction in order to increase the concentration of 2 BrCl in order to finally reach Q=K
12. What is a resonance structure?A. Alternate structures of similar compoundsb. Alternate structures of the same compoundC. Similar compounds with electrons added to themd. Similar compounds with electrons removed from them
There are some compounds in which the electrons move from one side to anothe, and it is a continous movement. For that reason, the resonance structure is created. It works as a theorical structure which is not exact, but it helps us to approach to the real structure.
For example, for the bencene, there are 3 different resonance structures:
And they are the same compound. It means that the answer is B. Alternate structures of the same compound.
A sample of gas with a mass of 1.45 g occupies a volume of 931 mL at a pressure of 733 Torr and a temperature of 16.0 ∘C . What is the molar mass of the gas?
Answer:
[tex]38.5\text{ g/mol}[/tex]Explanation:
Here, we want to get the molar mass of the gas
Let us call it M
From the ideal gas equation, we can get the number of moles of the gas
Mathematically:
[tex]\begin{gathered} PV\text{ = nRT} \\ n\text{ = }\frac{PV}{RT} \end{gathered}[/tex]Also, n is the mass divided by the molar mass of the gas:
[tex]\begin{gathered} \frac{m}{M}\text{ = }\frac{PV}{RT} \\ \\ M\text{ = }\frac{mRT}{PV} \end{gathered}[/tex]Where:
M is the molar mass that we want to calculate
m is the mass of the gas sample which is 1.45 g
P is the gas pressure which is 733 torr (to convert to atm, we multiply by 0.00131579 : 733 * 0.00131579 = 0.96 atm)
V is the volume which is 931 mL (We convert to L by dividing by 1000:
931/1000 = 0.931 L)
R is the molar gas constant which is 0.0821 L.atm/mol.K
T is the temperature that we convert to K by adding 273 K : 273 + 16 = 289 K)
Substituting the values, we have it that:
[tex]M\text{ = }\frac{1.45\text{ }\times0.0821\text{ }\times289}{0.96\times0.931}\text{ = 38.5 g/mol}[/tex]I need help on this!! it’s due today! will mark brainliest if it’s correct
Nuclear fission causes a neutron to split the isotope U-235 when it collides with its nucleus. When a slow neutron interacts with a heavy nuclide like 235U, nuclear fission can occur (0.025 eV).
What happens when uranium-235 atoms are bombarded by slow moving neutrons?When a slow neutron interacts with a heavy nuclide like 235U, nuclear fission can occur (0.025 eV). If a fission (or splitting apart) occurs, the nuclear material splits into two (on average) about equal fragments that travel away with kinetic energy, producing heat.
Nuclear fission causes a neutron to split the isotope U-235 when it collides with its nucleus. Two or three additional neutrons as well as fission products are released during this fission process. The chain reaction is continued by some of the emitted neutrons. There is significant energy released in every fission reaction.
When a uranium atom divides, additional neutrons are also released. The process keeps repeating again as these neutrons keep crashing into more uranium atoms. This process is called a nuclear chain reaction. This reaction is controlled in nuclear power plant reactors to produce a desired amount of heat.
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2A + C + D + EDetermine the enthalpy(AH)in kJ of the above reaction using the reactions below:1B → C AH = 415.3 kJA + 1B →D AH = -95.7 kJ6A ->6E AH = 207.9 kJ
Explanations:
• We will follow Hess's Law of Constant Heat Summation:
(that states that if a reaction occurs in more than one route, then the the total enthalpy change for the reaction is the sum of all changes.)
For reaction :
[tex]\begin{gathered} B\Rightarrow C\text{ }\Delta H\text{ = 415.3 kJ }\ldots\text{.}\mathrm{}(\text{ reaction 1)} \\ A+B\text{ }\Rightarrow\text{ D }\Delta H\text{ = -95.7kJ}\ldots.(\text{ reaction 2 ) } \\ 6A\text{ }\Rightarrow6E\text{ }\Delta H\text{ = 207.9kJ }\ldots\ldots(\text{reaction 3 ) } \end{gathered}[/tex]∆H total =( reaction 3 )/6 +reaction 2 - reaction 1this can be expressed as :
[tex]\begin{gathered} \Delta H_{total\text{ }}=\text{ }\frac{207.9}{6\text{ }}+(-95.7\text{ ) - 415}.3\text{ } \\ \text{ = 34.65 -95.7 -415.3} \\ \text{ =-476.35kJ} \end{gathered}[/tex]This means that ∆H total= -476.35kJ.
71.11 Liters of nitrogen gas combined with 60.6 liters of oxygen gas. What volume of nitrogen dioxide gas is made?
The reaction to produce nitrogen dioxide from nitrogen and oxygen is as follows:
[tex]N_{2(g)}+2O_{2(g)}\rightarrow2NO_{2(g)}[/tex]Since all the reactants and products are gases, we can take the coefficients as liters of substance.
Dividing the volumes we have of each reactant by their corresponding coefficient we can determine the limit reagent:
[tex]\begin{gathered} \frac{71.11LN_2}{1LN_2}=71.11 \\ \frac{60.6LO_2}{2LO_2}=30.3 \end{gathered}[/tex]From this we can conclude that the limit reagent is oxygen.
We have to base our calculations on this substance.
According to the given equation, 2 L of O2 produce 2 L of NO2, use this ratio to find the volume of nitrogen dioxide produced:
[tex]60.6LO_2\cdot\frac{2LNO_2}{2LO_2}=60.6LNO_2[/tex]It means that 60.6 liters of nitrogen dioxide gas are made.
A 0.15M solution of methylamine CH3NH2 contains an unknown concentration of methylamine chloride CH3NH3Cl. If the solution has a pH of 10.20,what is the concentration of methylamine chloride in the solution? Kb for methylamine =4.6*10^-4
The concentration of methylamine chloride in the solution is 0.44 M.
given that :
concentration of methylamine , [ base ] = 0.15 M
pH = 10.20
pH + pOH = 14
pOH = 14 - pH = 14 - 10.20 = 3.8
Kb = 4.6 × 10⁻⁴
concentration of methylamine chloride , [ acid ] = ?
The equation of POH is given by the following formula :
POH = pKb + log [ acid ] / [ base ]
pkb = -log kb
pkb = - log ( 4.6 × 10⁻⁴ )
pkb = 3.33
now, substituting the values, we get:
POH = pKb + log [ acid ] / [ base ]
3.8 = 3.33 + log [ acid ] / [ 0.15 ]
0.47 = log [ acid ] / [ 0.15 ]
10^0.47 = [ acid ] / [ 0.15 ]
2.95 = [ acid ] / [ 0.15 ]
[ acid ] = 0.44 M
Thus, A 0.15M solution of methylamine CH3NH2 contains an unknown concentration of methylamine chloride CH3NH3Cl. If the solution has a pH of 10.20,what is the concentration of methylamine chloride in the solution is 0.44 M.
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In the reaction 2H2 + O2 →2H2O if 14grams of H2 react, how many grams of water could be produced?
Answer:
Explanation:2H2 + O2 —-> 2H2O
The mole ratio of H2 to H2O is 2 : 2 = 1:1
4 moles of H2 = 4 moles of H2O
Moles of H20 = 4mol
Molar mass of H2O = 18g/mol
Mass = moles X Molar mass
= 4mol x 18g/mol
= 72g
how many molecules are there in 2.13 moles of sodium bromide
Answer:
121 I think not sure tbh......
Can someone help me with this pls 2. Which is the volume of 3.20 moles of O₂?7. Which is the volume of 100. of O₂?
2. Which is the volume of 3.20 moles of O₂?
We are told that at STP one mol of any gas occupies 22.4 L. We will use that relationship to find the volume occupied by 3.20 moles of O₂.
1 mol of O₂ = 22.4 L
volume of O₂ = 3.20 moles of O₂ * 22.4 L/(1 mol of O₂)
volume of O₂ = 71.7 L
Answer: 3.20 moles of O₂ occupies 71.7 L
7. Which is the volume of 100. g of O₂?
In this case we will use the same relationship, but we are given grams instead of moles. So first we have to convert the mass in grams into moles. To do that we use the molar mass of O₂.
atomic mass of O = 16.00 amu
molar mass of O₂ = 2 * 16.00
molar mass of O₂ = 32.00 g/mol
Once that we know that the mass of 1 mol of O₂ is 32.00 g, we can find the number of moles that we have in 100. g of it.
moles of O₂ = mass of O₂ /(molar mass of O₂)
moles of O₂ = 100. g/(32.00 g/mol)
moles of O₂ = 3.13 moles
Finally we can find the volume that 3.13 moles of O₂ occupies (remember that 1 mol of any gas occupies 22.4 L at STP).
volume of O₂ = 3.13 moles * 22.4 L/(1 mol)
volume of O₂ = 70.1 L
Answer: 100. g of O₂ occupies 70.1 L
4. Which atom (magnesium or chlorine) has a higher ionization energy?___________________________(you should also be prepared to answer the question if asked for lower ionization energy)4a. Explain why the atom has a higher ionization energy. Include the definition of ionization energy and the reason why the atom you chose would have a higher value.
Answer:
The Chlorine atom has higher ionization energy.
Explanation:
Ionization energy is the energy needed to separate an electron from an atom of an element in the gaseous state.
In the Periodic Table of Elements, Ionization energy increases from bottom to top (in a group), and increases from left to right (in a period).
In the folowing drawing we can see the variation of the Ionization energy and the location of the magnesium atom and chlorine atom:
Magnesium atom and Chlorine atom are located in the same period, but Mg is in group 2 (left side) and Cl in in group 17 (right side), so the Chlorine atom has higher ionization energy.
What is the MOST likely reason a large retailer would have a digital forensics lab?
A.
to investigate online shopping fraud
B.
to hack into their customers’ computers
C.
to find out who is shoplifting in their stores
D.
to help local communities solve major crimes
Answer:
A
Explanation:
In-house forensics allows companies to work faster, cheaper, and potentially better than law enforcement. Labs at large companies are more likely than police labs to have high-tech tools and the latest forensics software, said Seigfried-Spellar.