Answers
Answer:
0.009: only 1 significant figure, since all zero digits are leading zeros;
0.030: there are 2 significant figures;
140: there are 3 significant figures (a simple way to check is convert this number to the scientific notation keeping the same amount of digits: 1.40 x 10^2);
2000: there are 4 significant figures;
80.30: there are 4 significant figures;
80060: there are 5 significant figures
0.05200: there are 4 significant figures.
Explanation:
The question requires us to identify the numbr of significant figures for each of the following values:
0.009
0.030
140
2000
80.30
80060
0.05200
Significant figures or significant digits of a number can be defined as the digits that define the resolution or precision of a number. In other words, the significant figures of a number are the reliable digits necessary to indicate the quantity of something.
There are a few rules to identify the amount of significant digits of a number. We can summarize them as:
- non-zero digits that are in the number are significant;
- zeros between two non-zero digits are significant;
- leading zeros (zeros to the left of the first non-zero digit) are not significant, while zeros to the right of the last non-zero digit in a decimal number are signifcant (for example, 0.005200 -> these zeros are not significant; 0.005200 -> these zeros are significant);
- zeros to the left of the last non-zero digit in an integer number may or may not be significant, depending on the measurement resolution.
Next, let's analyze the numbers given by the question:
0.009: only 1 significant figure, since all zero digits are leading zeros;
0.030: there are 2 significant figures;
140: there are 3 significant figures (a simple way to check is convert this number to the scientific notation keeping the same amount of digits: 1.40 x 10^2);
2000: there are 4 significant figures;
80.30: there are 4 significant figures;
80060: there are 5 significant figures
0.05200: there are 4 significant figures.
-
Related Questions
Howmany molecules of iron (iii) oxide canbe produced from 13.5 molesFe
Answers
Calculations:
Balanced Reaction :
[tex]2Fe+3O_2\Rightarrow2Fe_2O_3[/tex]1. by stoichiometry,• 2 moles of Fe : 2 moles of iron (iii) oxide
• then 13.5 moles Fe : x
X = 13.5 *2 /2 = 13.5 moles of Fe
• This means that 13.5 mole of Fe2O3 will be produce.
2. Calculate number of molecules by Avogardo principles.No. of molecules = Moles * Avogardo Number
[tex]\begin{gathered} Fe_2O_{3\text{ }}Molecules\text{ = 13.5 moles }\cdot6.022\cdot10^{23} \\ \text{=8.1297}\cdot10^{24} \end{gathered}[/tex]• This means that there are 8.1297 x10^24molecules of Fe2O3 from 13.5 moles Fe.
Calculate the percentage oxygen in dinitrogen pentoxide
Answers
So, To calculate the mass percentage of dinitrogen pentoxide (N2O5) we will first calculate the molar weight of the molecule. The mass percentage will be calculated with the following equation:
[tex]\text{Mass percentage = }\frac{\text{Molar Mass oxygen}}{MolarmassmoleculeN_2\text{O}_5}\times100[/tex]Molar mass will be:
Element Atomic Mass #Atoms Mass
N 14.0067 2 28.0134 g/mol
O 15.9994 5 79.997 g/mol
Total mass = 28.0134 + 79.997 = 108.0104 g/mol
[tex]\text{Mass percentage = }\frac{\text{7}9.997}{108.0104}\times100\text{ = }74.064\text{ percent}[/tex]An unknown gas is found to consist of 10.48 g of nitrogen and 11.96 g if oxygen. What is the percentage composition of this gas? * A. 53.3% N, 46.7% O B. 74.5% N, 25.5% O C. 28.6% N, 71.4 % O D. 46.7%N, 53.3%O
Answers
Answer:
A. 53.3% N, 46.7% O
Explanation:
1st) It is necessary to add both quantities (10.48g of nitrogen and 11.96g of oxygen) to obtain the total mass of the sample, which represents 100%:
10.48g + 11.96g = 22.44g
22.44g represents the 100% of the sample.
2nd) Now we can calculate the percentage composition of the gas, using a mathematical rule of three and the amount of nitrogen and oxygen:
• Nitrogen:
[tex]\begin{gathered} 22.44g-100\% \\ 10.48g-x=\frac{10.48g*100\%}{22.44g} \\ x=46.7\% \end{gathered}[/tex]• Oxygen:
[tex]\begin{gathered} 22.44g-100\% \\ 11.96g-x=\frac{11.96g*100\%}{22.44g} \\ x=53.3\% \end{gathered}[/tex]We can also calculate the oxygen percentage by subtracting 100% minus the nitrogen percentage (46.7%):
100% - 4607% = 53.3%
So, the percentage composition is 53.3% N and 46.7% O.
Given 20 grams of Na (s) and 10 grams of Cly, which reactant is in excess? And, how much NaCl should be produced from these amounts of the two reactants?
Answers
In order to answer this question we will need a few steps
First one will be to set up the properly balanced equation:
2 Na + Cl2 -> 2 NaCl
20 grams of Na
10 grams of Cl2
From this balanced equation we see that the molar ratio between Na and Cl2 is 2:1, that means that for every 2 moles of Na, we will need 1 mol of Cl2 in order to proceed with the reaction
Now we need to identify the limiting and excess reactant, we will do that by checking how many moles of each element we have and how much we should have in order to properly react with the other element, let's check it:
Molar mass for Na is 23g/mol
23g = 1 mol
20g = x moles
x = 0.89 moles of Na in 20 grams
So if we have 0.89 moles of Na, we should have 0.44 moles of Cl2, but we don't know if we have this amount of moles of Cl2 in 10 grams of it, let's check
Molar mass for Cl2 is 71g/mol
71g = 1 mol
10g = x moles
x = 0.14 moles
We have fewer moles than we actually needed, let's do the same step but now focusing on Cl2
Cl2 in 10 grams has 0.14 moles, therefore we will have 0.28 moles of Na, remember the molar ratio 2:1
23g = 1 mol
x grams = 0.28 moles
x = 6.44 grams of Na
If we have 10 grams of Cl2, we would only need 6.44 grams of Na, since we have more available, we can say that Na is in excess and Cl2 is the limiting reactant
To find out the mass of NaCl produced from 10 grams of Cl2 (we have to use the limiting reactant), NaCl has a molar mass of 58.44g/mol and the molar ratio will be again 2:1, one mol of Cl2 and 2 moles of NaCl, if we have 0.14 moles of Cl2, therefore we will have 0.28 moles of NaCl
58.44 g = 1 mol
x grams = 0.28 moles
x = 16.4 grams, the value in the options is a little higher, but not too much higher, that must be due some rounding up
Letter A
What coefficients would correctly balance this equation?_Ag2S → _Ag +_ S₂
Answers
In order to properly balance an equation, we need to make sure that the same amount of elements on the reactants side matches the number of elements on the products side, we can do that by increasing the number in front of each molecule, the so called stoichiometric coefficient. In the reaction from the question we can properly balance by adding the following stoichiometric coefficients
For our question, we have:
2 Ag2S -> 4 Ag + S2
Zinc metal reacts with HCl according to the balanced equation:Zn + 2HCl à ZnCl2 + H2When 0.103 g of Zn is combined with enough HCl to make 50 mL of solution in a coffee-cup calorimeter, all of the zinc reacts, raising the temperature of the solution from 22.5 C to 23.7 C. Find the heat of the reaction. (ans: -160 kJ/mol)
Answers
-163kJ/mol
Explanations:Given the reaction between the zinc metal reacts with HCl according to the balanced equation:
[tex]Zn+2\text{HCl}\rightarrow\text{ZnCl}_2+H_2[/tex]The required heat of reaction will be calculated using the formula below:
[tex]\triangle H_{\text{rxn}}=-\frac{Q}{n_{Zn}}[/tex]where:
• Q is the ,heat produced
,• nZn is the, number of moles that reacted
The formula for calculating the quantity of heat produced is expressed as:
[tex]Q=mc\triangle\theta[/tex]where:
• m is the ,mass, of the ,Zinc metal
,• c is the ,specific heat capacity, of zinc
,• △θ is th,e change in temperature
Get the mass of zinc
[tex]\begin{gathered} \text{mass}=\text{ }density\times\text{volume} \\ m=\rho\times v \end{gathered}[/tex]The quantity of heat becomes:
[tex]Q=\rho\cdot v\cdot C\triangle\theta[/tex]Substitute the given parameters to have:
[tex]\begin{gathered} Q=\frac{1.02\cancel{g}}{\cancel{mL}}\times50\cancel{mL}\times\frac{4.18J}{\cancel{g^oC^{}}}\times(23.7-22.5)\cancel{^oC} \\ Q=1.02\times50\times4.18\times1.2 \\ Q=255.8Joules \end{gathered}[/tex]Next is to get the number of moles of Zinc that reacted (nZn)
[tex]\begin{gathered} nZ_n=\frac{Mass}{\text{Molar mass}} \\ nZ_n=\frac{0.103g}{65.4g\text{/mol}} \\ nZ_n=0.00157mole \end{gathered}[/tex]Get the required heat of reaction of Zinc:
[tex]\begin{gathered} \triangle H_{\text{rxn}}=-\frac{Q}{nZ_n} \\ \triangle H_{\text{rxn}}=-\frac{255.8Joules}{0.00157moles} \\ \triangle H_{\text{rxn}}=-162,929.93J\text{/mol} \\ \triangle H_{\text{rxn}}\approx-163kJ\text{/mol} \end{gathered}[/tex]Hence the heat of the reaction of Zinc is approximately -163kJ/mol
2. In each pair, CIRCLE the larger species.a. N or N3-b. Ca or Ca2+c. Si or Asd. Al or B
Answers
Answer:
a. N3-
b. Ca
c. As
d. Al
Explanation:
a. N or N3-
In this case, the largest species is N3- because it has 3 additional electrons in contrast to the neutral atom.
b. Ca or Ca2+
In this case, the largest species is Ca, because Ca2+ has 2 fewer electrons than the neutral atom of Ca.
c. Si or As
To analyze these elements, is is necessary to look for them in the Periodic Table of elements:
Since the atomic radius increases from top to bottom and from right to left, the largest is As.
d. Al or B
In this case, we also have to look for the elements in the Periodic table, and following the atomic radius increase, the largest is Al.
For the following reaction, 0.156 moles of sulfuric acid are mixed with 0.567 moles of calcium hydroxide.
Answers
The first step is to write the reaction using the molecular formulas of the substances:
[tex]H_2SO_4+Ca(OH)_2\rightarrow CaSO_4+2H_2O[/tex]Now that the equation is balanced, we have to divide the amount of each reactant by its stoichiometric coefficient, that in this case is 1 for both of them:
[tex]\begin{gathered} \frac{0.156mol}{1}=0.156mol \\ \frac{0.567mol}{1}=0.567mol \end{gathered}[/tex]The least result will indicate the limiting reagent, which in this case is sulfuric acid. It means that its formula is H2SO4.
Basing our calculations in this reagent, we can find the maximum amount of calcium sulfate that is produced:
[tex]0.156molH_2SO_4\cdot\frac{1molCaSO_4}{1molH_2SO_4}=0.156molCaSO_4[/tex]It means that the maximum amount of calcium sulfate that can be produced is 0.156 moles.
If there are 1.1 moles of SeCl6 how many moles of Cl2 will be produced? Use up to one decimal point
Answers
ANSWER
There are 3.3 moles of Cl2 in 1.1 moles of SeCl6
EXPLANATION
Given that
The number of moles of SeCl6 is 1.1 moles
Firstly, write a balanced equation of the reaction
[tex]\text{ SeCl}_6\text{ }\rightarrow\text{ Se + 3Cl}_2[/tex]In the reaction above, 1 mole SeCl6 gives 3 moles Cl2
Let x be the number of moles of Cl2
[tex]\begin{gathered} \text{ 1 mole SeCl}_6\text{ }\rightarrow\text{ 3 moles Cl}_2 \\ \text{ 1.1 mole SeCl}_6\text{ }\rightarrow\text{ x moles Cl}_2 \\ \text{ cross multiply} \\ \text{ 1 mole SeCl}_6\times\text{ x moles Cl}_2\text{ = 1.1 mole SeCl}_6\text{ }\times\text{ 3 moles Cl}_2 \\ \text{ Isolate x } \\ \text{ x = }\frac{1.1moles\cancel{SeCl_6}\times\text{ 3 moles Cl}_2}{1mole\cancel{SeCl_6}} \\ \\ \text{ x = 1.1 }\times\text{ 3} \\ \text{ x = 3.3 moles} \end{gathered}[/tex]Therefore, there are 3.3 moles of Cl2 in 1.1 moles of SeCl6
Determine the molarity of a solution with a volume of 707. mL and 0.610 mol of solute dissolved.Answer: ____ M
Answers
Molarity or molar concentration is a measure of the concentration of a chemical species, of a solute in a solution, using as units, number of moles, and volume in liters. The formula for Molarity is:
M = n/V
Where:
n = number of moles, 0.610 moles
V = volume in Liters, 0.707
Now we add these values into the formula:
M = 0.610/0.707
M = 0.863 M is the molarity
What is the wavelength of light with a frequency of 3.215 x 10^15 s-¹?
A. 9.325 x 10^-8m
B. 3.110 x 10^-16m
C. 1.072 x 10^7 m
D. 9.639 x 10^23m
Answers
The wavelength of the light will be 9.63 × 10²³ m .The wavelength of the wave is calculated using the frequency formula.
The quantity of cycles finished in a certain amount of time is known as frequency. It also indicates the number of crests that pass past a specific position in a unit of time. It is often referred to as the reciprocal of time. Hertz are used to express frequency (Hz). The frequency of the wave is calculated using the frequency formula.
The total number of times a repeated event occurs in a unit of time is known as its frequency. Depending on the quantities known, various frequency formulas exist to calculate frequency. The terms frequency (f), time period (T), wave speed (V), and wavelength () are all found using the formula for the frequency of a wave.
We know that ,
Frequency= Speed of light/ wavelength
Wavelength= Frequency × Speed of light
= 3.215 ×10¹⁵ × 2.997× 10⁸
= 9.639 × 10²³ m
The wavelength will be obtained by frequency -wavelength formula a and it will come as 9.63 × 10²³ m .
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Select the correct structure thatcorresponds to the name.2-hexyneA.CH3CH₂CH₂C=CCH3B. CH3C CCH₂CH₂CH3C. both
Answers
Answer
c. both
explanation
both structures have a triple bond on the second carbon and the have 6 carbons in the carbon chain
Calcium reacts with Aluminum chloride to form Calcium chloride and Aluminum. If you react 100 grams of Aluminum chloride with Calcium, how many grams of Aluminum are produced?
Answers
38.95 g of Al is produced on reacting 100 g of Aluminium chloride with Calcium.
We need to write a balanced equation for the reaction. This is illustrated below:
2AlCl₃ + 3Ca —> 3CaCl₂ + 2Al
Molar Mass of AlCl₃
= 27 + (3x35.5)
= 27 + 106.5 = 133.5g/ mol
Mass of AlCl₃ from the balanced equation
= 2 x 133.5g
= 267g
Molar mass of Al= 26
Mass of Al from balanced equation= 2×26
= 52
Molar Mass of CaCl₂ = 40 + (2 x 35.5)
= 40 + 71 = 111g/mol
Mass of CaCl₂ from the balanced equation
= 3 x 111 = 333g
From the equation,
133.5g of AlCl₃ produced 52g of Al
Therefore, 100g of AlCl₃ will produce
= (100 x 52)/133.5
= 38.95g of Al
So, 38.95 g of Al is produced on reacting 100 g of Aluminium chloride with calcium.
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Select the statements that are true about electronegativity between elements, and their type of bond.A.If the difference is over 1.0, an ionic bond will form.B.If the difference in electronegativity is 0 to 0.5, the bond will be polar covalent.C.If the difference in electronegativity is from 0.6 to 1.7, the bond will be polar and covalent.
Answers
Answer:
C. If the difference in electronegativity is from 0.6 to 1.7, the bond will be polar and covalent.
Explanation:
Let's see the type of bondings based on the electronegativity differences between atoms:
[tex]\begin{gathered} less\text{ than 0.4 : Nonpolar covalent.} \\ 0.4\text{ - 1.7 :}Pola\text{r covalent.} \\ Greater\text{ than 1.7: Ionic.} \end{gathered}[/tex]So based on this, the answer would be C. If the difference in electronegativity is from 0.6 to 1.7, the bond will be polar and covalent.
10.Which of the following elements is correctly matched with the number of electrons it needs to become stable?Select one:a. Sulfur (S) .. 6b. Hydrogen (H) .. 2c. Chlorine (Cl) .. 1d. Aluminum (Al) .. 3
Answers
Chlorine (Cl). Option C is correct
Explanations:For an elements to be stable, it must attain its octet configuration that is the total number of electron in its outermost shell is must be 8 electrons.
For sulphur (atomic number of 16) with an electronic configuration 1s^2 2s^2 2p^6 3s^2 3p^4. This shows that sulphur needs 2 electrons to complete its shell making the first option incorrect.
For hydrogen (atomic number of 1) will need one electron to attain duplet rule making the option B is incorrect.
For chlorine element (atomic number of 17), with electronic configuration 1s^2 2s^2 2p^6 3s^2 3p^5. This shows that chlorine will need 1 more electron to make it stable
Is there any difference(s) in observation and molarity of the strong base when phenolphthalein or methyl orange is used? If Yes / No account for this reason.
Answers
Yes, the molarity in both the cases will be different if the indicator is changed from methyl orange to phenolphthalein or from phenolphthalein to methyl orange.
Since molarity is defined as the Molar concentration, also known as molarity, amount concentration, or substance concentration, is a unit used to describe the amount of a substance in a solution expressed as a percentage of the volume of the solution or it is the number of moles of solute divided by volume of solution in liters.
So on changing indicator, the number of moles changes as the molar mass is changing, so the molarity and other observations will get changed too and may increase or decrease.
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I would like some help to solve this problem number 1
Answers
A chemical equation is known to be balanced if the total number of moles of elements at the reactant is equal to that of the product.
For the reaction between sodium chloride (NaCl) and potassium nitrate (KNO₃), the balanced reaction is given as;
[tex]\text{NaCl}+\text{KNO}_3\rightarrow KCl+NaNO_3[/tex]You can see that the reactant ions exchange places to form new products (potassium chloride and sodium nitrate). This shows that the equation is a double displacement reaction
I need help getting the answer on all of theseFirst one
Answers
The Law of Conservation of Mass can be state in different ways. Essentially, this law states that if we are on a closed system, no mass can be created nor dstroyed. In chemical terms, this means that in a chemical reaction the number of atoms of each element has to be the same in the reactants and the products.
Turn the following word equation into a symbolic equation: potassium hydroxide and hydrobromic acid react to form potassium bromide and water.
Answers
The chemical formula of potassium hydroxide is KOH.
The chemical formula of hydrobromic acid is HBr.
The chemical formula of potassium bromide is KBr.
The chemical formula of water is H2O.
The symbolic equation for this reaction is:
[tex]KOH+HBr\rightarrow KBr+H_2O[/tex]It means that the correct answer is the first choice.
What are the OSHA PEL-TWyA and PEL-STEL values for nitric acid?
Answers
The OSHA limit for STEL-TWA is 2ppm and the PEL-STEL value is 4ppm to the exposure to nitric acid.
OSHA refers to Occupational Safety and Health Administration has adopted standard values for the exposure to harmful and hazardous chemicals so that the safety of workers and testing animals could be ensured.
Here, STEL-TWA stands for Short Term Exposure Limit - Time-Weighted average, and PEL-STEL stands for Permissible Exposure Limit- Short Term Exposure Limit.
This is usually set up in industries to ensure the safety of the workers and the maximum exposure short-term time limit is 15min and 2ppm for STEL-TWA and 4 ppm for PEL-STEL.
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Which of the following combinations will form a solution?Group of answer choicesOil and waterSand and waterSugar and waterSand and sugar
Answers
Answer: the combination "sugar and water" will form a solution.
Explanation:
The question requires us to determine which of the combinations given will form a solution.
To solve this question, let's consider this definition of solution: a homogenous mixture of two or more substances in relative amounts. This means that, to be considered a solution, two mixed substances must form a homogeneous mixture, i.e., without separation of phases.
Considering the options given by the question, we can say:
- oil and water do not mix (because they have different polarities), and separate in different phases when are put together;
- sand and water do not form a homogeneous mixture: sand is deposited at the bottom of the vessel and forms a separated phase of solid;
- sugar and water can form a homogeneous mixture, therefore they form a solution;
- sand and sugar form visible separated phases when mixed together (we can see the particles of sugar and sand separated).
Therefore, considering the points above, we can say that only sugar and water form a solution.
Consider the following reaction:
Mg²⁺(aq) + Cu(s) → Cu²⁺(aq) + Mg(s).
In this reaction, Mg²⁺(aq) is: ________
Answers
separate an oxidation-reduction equation into 2 half equations one for oxidation and one for reduction.
cu(s) ⇒ [tex]cu^{2+}[/tex](aq) + 2e- ........ oxidation
[tex]mg^{2+}[/tex](aq) + 2e- ⇒ mg(s) ...........reduction
as with all chemical equations one must balance mass and charge both.
An oxidizing agent causes another substance to be oxidized.The oxidizing agent is reduced.in other words to accept their electrons. Common oxidizing agents are oxygen, hydrogen peroxide and the halogens.
A reducing agent causes another substance to be reduced. the reducing agent is oxidised.for example hydrogen carbon hydrogen sulfide and Ammonia are reducing agents
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What volume of O2 collected at 22.0 degrees Celsius and 728mmHg would be produced by the decomposition of 8.15g KClO3
Answers
The volume of O₂ collected at 22 degrees Celsius and 728 mmHg would be produced by the decomposition of 8.15 grams of KClO₃ is 2.52 L
It is given that the mass of KClO₃ is 8.15g and the temperature is 22°C and the pressure is 728mmHg. The number of moles of KClO₃ is given by,
No of moles of KClO₃ = 8.15/122.55
No of moles of KClO₃ = 0.066 mol
The reaction for decomposition is,
2KClO₃ -----------> 2KCl + 3O2
2 mol of KClO3 gives 3 moles of O₂
Then, 0.66mol of KClO3 gives, 3/2(0.66) mol of O₂ which is 0.0998
The given temperature is 22 + 273 = 295K
The given pressure is 728mmHg which is 728/760 which is 0.958 atm
We know that
PV = nRT
0.958 x V = 0.0998x 0.0821x295
V = 2.52L
Therefore, the volume of Oxygen collected is 2.52L
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How many L of solution do you have if you dissolve 5 moles of salt in enough water to make a 0.5 M solution?
Answers
10L
Explanations:The formula for calculating the molarity of a solution is expressed as:
[tex]molarity=\frac{moles}{volume}[/tex]Given the following parameters
• Moles of salt = 5 moles
,• Molarity of solution = 0.5M
Substitute the given parameters into the formula
[tex]\begin{gathered} volume=\frac{moles}{molarity} \\ volume=\frac{5moles}{0.5M} \\ volume=10L \end{gathered}[/tex]Hence the required volume of the solution is 10L
The Croatian seismologist, Andrija Mohorovicic, discovered a boundary change in the Earth's layers. Please explain how he discovered this using two to three sentences using your best grammar.
Answers
The Croatian seismologist, Andrija Mohorovicic, discovered a boundary change in the Earth's layers because he noticed that P-waves were refracted at the boundary.
Who is a seismologist?Seismologists are described as Earth scientists, specialized in geophysics, who study the genesis and the propagation of seismic waves in geological materials.
Andrija Mohorovicic realized that as one crosses the boundary the predominant mineral composition of the rock changes, and the minerals on the mantle side enable seismic waves to travel faster.
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Given the following reaction:2 Li (s) + 2 H2O (I) = 2 LiOH (aq) + 1 H2 (g)How many grams of solid lithium must be used in this reaction in order to obtain 6.00 L of hydrogen gas at 1.10 atm and 25.0 C ?
Answers
Answer:
3.73 g of Li.
Explanation:
What is given?
Volume of hydrogen gas, H2 (V) = 6.00 L.
Pressure (P) = 1.10 atm.
Temperature (T) = 25.0°C + 273 = 298 K.
R = 0.082 L*atm/mol*K.
Step-by-step solution:
First, we have to find the number of moles of hydrogen gas (H2) using the ideal gas formula:
[tex]PV=nRT,[/tex]where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant and T is the temperature on Kelvin scale. So let's solve for 'n' and replace the given values:
[tex]n=\frac{PV}{RT}=\frac{1.10\text{ atm}\cdot6.00\text{ L}}{0.082\text{ }\frac{L\cdot atm}{mol\cdot K}\cdot298K}=0.270\text{ moles.}[/tex]Based on this, we have 0.270 moles of H2.
You can see in the chemical equation that 2 moles of Li reacted produce 1 mol of H2, so we have to state a rule of three:
[tex]\begin{gathered} 2\text{ moles Li}\rightarrow1\text{ mol H}_2 \\ ?\text{ moles Li}\rightarrow0.270\text{ moles H}_2 \end{gathered}[/tex]The calculation will look like this:
[tex]0.270\text{ moles H}_2\cdot\frac{2\text{ moles Li}}{1\text{ mol H}_2}=0.540\text{ moles Li.}[/tex]The final step is to convert 0.540 moles of Li to grams using its molar mass that can be found in the periodic table, which is 6.9 g/mol:
[tex]0.540\text{ moles Li}\cdot\frac{6.9\text{ g Li}}{1\text{ mol Li}}=3.73\text{ g Li.}[/tex]The answer is that we must use 3.73 g of Li to produce 6.00 L of H2 at 1.10 atm and 25.0 °C.
A 14.577 g sample of CaCl2 was added to 12.226 g of K2CO3 and mixed in water. A 3.554 g yield of CaCO3 was obtained. Calculate the percent yield of CaCO3.
Answers
A 14.577 g sample of CaCl₂ was added to 12.226 g of K₂CO₃ and mixed in water. A 3.554 g yield of CaCO₃ was obtained then the percent yield of CaCO₃ is 13.25%
Here given data is
14.577 g CaCl₂ was added to 12.226 g of K₂CO₃ and mixed in water
3.554 g yield of CaCO₃ was obtained
We have to calculate the percent yield of CaCO₃ = ?
Percent yield = actual yield/threotical yield×100
Actual yield = 3.554 g
Theroetical yield = 14.577 g CaCl₂ + 12.226 g of K₂CO₃
Theroetical yield = 26.803g
Now Percent yield = actual yield/threotical yield×100
Percent yield = 3.554 g /26.803g×100
Percent yield = 13.25%
The percent yield of CaCO₃ is 13.25%
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Which of the following is not an empirical formula?H2O2HOH2OH3O
Answers
An empirical formula is the simplest form of a formula, that is, the subscripts are simplified.
Therefore, the answer is H2O2 because it's not the simplest form.
3.21 X 10^54 atoms of nitrogen=___ moles of nitrogen.
Answers
Answer:
[tex]5.33\text{ }\times\text{ 10}^{30\text{ }}\text{ moles}[/tex]Explanation:
Here, we want to get the number of moles of nitrogen
Mathematically:
[tex]1\text{ mole of nitrogen = 6.02 }\times\text{ 10}^{23}\text{ atoms}[/tex]3.21 * 10^54 atoms of nitrogen will contain:
[tex]\frac{3.21\times10^{54}}{6.02\text{ }\times\text{ 10}^{23}}\text{ = 5.33 }\times\text{ 10}^{30\text{ }}\text{ moles}[/tex]Which of the following methods would be most useful for describing atoms
Answers
Explanations: Atoms are very small to be observed vissually, as a reslt we need the construction of a model to be able to successfully describe an atom.