Answer:
C
Explanation:
I just took the test
Answer:
B
Explanation:
A sample of compound contains 5.65x10 21 molecules molar mass of the compound is 89.06g/ mol determine the mass of the sample in grams
Answer:
Explanation:
no of molecules=5.65*10^21
NA=6.23*10^23
no of moles=no of molecules/avogadro number
no of moles=5.65*10^21/6.23*10^23
no of moles=9.07*10^-3
now we know that
no of moles=mass/molar mass
mass=no of moles*molar mass
mass=9.07*10^-3*89.06
mass=0.808 g
A student measures the length of two pieces of paper as 8.21 in
and 8.0 in. What is the total length? Be sure to use sig. figs. in
your answer. Do not include the unit.
Answer: 16.21
Explanation:
A student measures the length of two pieces of paper as 8.21 in and 8.0 in. the total length is 16.21 with 4 significant figures.
What are significant figures?
The significant figures or digits are the form of scientific methd which represent the digit from zero to nine and use when the value is uncertain where starting zeros are not significant and decimal is also not a significant figure.
In the given value the total is 16.21 with 4 significant figures with it has 4 significant digits and the decimal with it is not significant after adding from which the respective value is here.
Therefore, with 4 significant figures where the student measures the length of two pieces of paper as 8.21 in and 8.0 in. the total length is 16.21.
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1. If a solution of sodium chloride has 22.3 g of
NaCl, and a volume of 2.00 L, what is its molarity?
We are given:
Mass of NaCl in the given solution = 22.3 grams
Volume of the given solution = 2 L
Number of Moles of NaCl:
We know that the number of moles = Given mass / Molar mass
Number of moles = 22.3 / 58.44 = 0.382 moles
Molarity of NaCl in the Given solution:
We know that Molarity of a solution = Moles of Solute / Volume of Solution(in L)
Molarity = 0.382 / 2
Molarity = 0.191 M
Convert 85.02g to mg (1 mg=10^-3g)
Answer:
85,020 milligrams
Explanation:
Multiply the mass value by 1,000
Theodor Schwann was a German scientist who wanted to understand how different types of cells worked and performed functions in different tissues. He was one of the first to theorize that all living things are made up of cells.
Rudolf Virchow was a German doctor who wanted to discover the origin of diseases. He accepted the idea that all living things are made up of cells and extended the idea to theorize that many diseases are the result of bacterial cells infecting the body.
The example described above suggests that
A.
scientific discoveries are never made by doctors.
B.
scientists always have the same goals when making related discoveries.
C.
German scientists were the first to disprove cell theory.
D.
people with different goals can make contributions to scientific knowledge.
D. People with different goals can make contributions to scientific knowledge
Both Schwann and Virchow had different thoughts and ideas. Schwann wanted to understand how cells worked - Virchow wanted to know the origin of diseases. Different goals.
Answer:
D
Explanation:
I got it right on studyisland
How many moles of H are present in 3 moles of carbon trihydride?
Answer:
4moles of carbon trihydride
At 298 K and 1 atm which noble gas has the lowest density? Why?
1) Ne
2) Kr
3) Xe
4) Rn
Answer:
Ne
Explanation:
It has the lowest density.
Neon has the lowest density since it has the smallest atomic size and the lowest atomic number.
At a standard temperature of 298K and a pressure of 1 atm;The atomic density of an element refers to the number of atoms contained in an element per unit volume.
The size of an atom has an effect on atomic density. The size of an atom increases from left to right across the period and top to bottom down the group.
As such, on the periodic table, as we move from top to bottom down the group, the density of an atom increases.
The atomic element of the given elements are:
Neon (Ne) = 10Krypton (Kr) = 36Xenon (Xe) = 54Radon (Rn) = 36Therefore, we can conclude that Neon (Ne) will have the lowest density since it has the smallest atomic size and the lowest atomic number.
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The enthalpy change of reaction 1 is -114 kJ mol-1
reaction 1
2NaOH(aq) + H2SO4(aq)
→ Na2SO4(aq) + 2H2O(1)
By using this information, what is the most likely value for the enthalpy change of reaction 2?
reaction 2
Ba(OH)2(aq) + 2HCl(aq) → BaCl2(aq) + 2H2O(1)
Answer:
-114kJ mol-1
Explanation:
Definition of the enthalpy change of neutralization: the energy released with the formation of 1 mole of water when neutralization takes place between an acid and a base.
Since both reactions yield the same number of moles of water, the answer should be -114kJ mol-1.
The statement for the enthalpy change of reaction 2 is "-114 kJ"
What is enthalpy change?The change in enthalpy (ΔH) is a quantity of heat of a system. The enthalpy change is the amount of heat that enters or exits a system during a reaction.
One equivalent of hydrogen ions is neutralised with one equivalent of hydroxide ions in the reaction 1,
NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)
The change in enthalpy is given as -114 kJ.
Two equivalents of hydrogen ions are neutralised with two equivalents of hydroxide ions in the reaction 2,
Ba(OH)2 + H2SO4 (aq) → BaSO4 (s) + 2H2O (l)
But, that primary ionic reaction is same for both the reaction in which hydrogen ion combines with hydroxide ion to generate a water molecule. So, the enthalpy change of reaction 1 would be exactly same as for reaction 2.
The neutralization enthalpy comes out to be -114 kJ.
Hence the correct answer is -114 kJ.
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Considering the patterns you have noticed in this activity, which statement best explains why a compound with the molecular formula CH3 doesn't exist in nature?
A. Hydrogen typically needs four bonds to reach a noble gas configuration.
B. Carbon needs more than just three bonds to reach a noble gas configuration. C. The chemical CH3 does not react with other substances because of its high stability.
D. CH3 has three double bonds, which fails to give it a noble gas configuration
Answer:
The answer is B
Explanation:
I had the same question and I chose B and it was correct.
Answer:
B. Carbon needs more than just three bonds to reach a noble gas
Explanation:
PLATO ANSWER
PLATO EXPLANATION-
Each hydrogen atom can make only one bond, but a carbon atom needs four bonds to be stable. Therefore, three hydrogen atoms are not enough for the carbon atom to make four bonds.
2. Suppose 13.7 g of C2H2 reacts with 18.5 g O2 according to the reaction below. C2H2(g) + O2(g) → CO2(g) + H2O(ℓ) a. What is the mass of CO2 produced? b. What is the limiting reagent?
Answer:
Mass of CO₂ produced = 20.328 g
Oxygen is limiting reagent.
Explanation:
Given data:
Mass of C₂H₂ = 13.7 g
Mass of O₂ = 18.5 g
Mass of CO₂ produced = ?
What is limiting reagent = ?
Solution:
Chemical equation:
2C₂H₂ + 5O₂ → 4CO₂ + 2H₂O
Number of moles of C₂H₂:
Number of moles = mass /molar mass
Number of moles = 13.7 g/ 26.04 g/mol
Number of moles = 0.526 mol
Number of moles of O₂:
Number of moles = mass /molar mass
Number of moles = 18.5 g/ 32 g/mol
Number of moles = 0.578 mol
Now we will compare the moles of CO₂ with C₂H₂ and O₂
C₂H₂ : CO₂
2 : 4
0.526 : 4/2×0.526 = 1.052
O₂ : CO₂
5 : 4
0.578 : 4/5×0.578 = 0.462
The number of moles of CO₂ produced by O₂ are less thus oxygen will be limiting reactant.
Mass of CO₂ produced:
Mass = number of moles × molar mass
Mass = 0.462 mol × 44 g/mol
Mass = 20.328 g
Is calcium oxide a Element or compound or mixture?
Answer:
compound
Explanation:
Answer:
The answer is compound
Explanation:
A 11.1-g sample of granite initially at 76.0°C is immersed into 22.0 g of water initially at 22.0°C. What is the final temperature of both substances when they reach thermal equilibrium? (For water, Cs=4.18J/g⋅∘C and for granite, Cs=0.790J/g⋅∘C.)
Answer:
[tex]T_f=26.7\°C[/tex]
Explanation:
Hello.
In this case, when two substances at different temperature are placed in contact in an isolated container, we can say that the heat lost by the hot substance is gained by the cold substance. In such a way, since granite is at 76.0 °C and water at 22.0 °C we infer granite is hot and water is cold, so we write:
[tex]Q_{granite}=-Q_{water}[/tex]
In terms of mass, specific heat and change in temperature, we write:
[tex]m_{granite}C_{granite}(T_f-T_{granite})=-m_{water}C_{water}(T_f-T_{water})[/tex]
Thus, since the temperature is the same for both substance, we can solve for it as shown below:
[tex]T_f=\frac{m_{granite}C_{granite}T_{granite}+m_{water}C_{water}T_{water}}{m_{granite}C_{granite}+m_{water}C_{water}}[/tex]
By plugging in each variable, we obtain:
[tex]T_f=\frac{11.1g*0.790\frac{J}{g\°C} *76.0\°C+22.0g*4.18\frac{J}{g\°C} *22.0\°C}{11.1g*0.790\frac{J}{g\°C} +22.0g*4.18\frac{J}{g\°C}}\\\\T_f=26.7\°C[/tex]
Best regards!
What happens to a Lithium atom for it to become an Li+1 ion?
Answer:
If an atom gains or loses an electron, it bacomes an ion. An atom that gains a negative electron, it becomes a negative ion. If it loses an electron it becomes a positive ion
Explanation:
A lithium atom has 3 protons and 3 electrons. It can lose one of its electrons, making it an ion. It now has more positive protons than electrons so it has an overall positive charge. Therefore it is a positive ion.
A fluorine atom will tend to gain, rather than lose, an electron. By gaining a negative electron, it has an overall negative charge. It has become a negative ion.
find the volume of a gas at standard pressure if its volume at 1.9 atm is 80 ml?
given:
formula:
substitution:
answer:
Answer:
1.5 × 10² mL
Explanation:
Step 1: Given data
Initial pressure of the gas (P₁): 1.9 atmInitial volume of the gas (V₁): 80 mLFinal pressure of the gas (P₂): 1.0 atm (standard pressure)Final volume of the gas (V₂): ?Step 2: Calculate the final volume of the gas
For an ideal gas, we can calculate the final volume of the gas using Boyle's law.
P₁ × V₁ = P₂ × V₂
V₂ = P₁ × V₁/P₂
V₂ = 1.9 atm × 80 mL/1.0 atm
V₂ = 1.5 × 10² mL
Since the pressure decreased, the volume of the gas increased.
THIS QUESTION IS HARD BUT I NEED HELP AND ITS DUE IN 20 MINS. YOU HAVE TO ANSWER A AND B FOR EVERYTHING TO BE CORRECT. I KNOW YALL ARE SMART PLSS HELP. THANKS!!
A bicycle has a momentum of 25.00 kg x m/s and a velocity of 2.5 m/s. What is the bicycle’s mass
Answer:
10 kgExplanation:
The mass of the bicycle can be found by using the formula
[tex]m = \frac{p}{v} \\ [/tex]
p is the momentum
v is the velocity
From the question we have
[tex]m = \frac{25}{2.5} \\ [/tex]
We have the final answer as
10 kgHope this helps you
5. What is the pH of an aqueous solution of the strong acid, Perchloric Acid (HClO4), with a concentration of 0.007 M?
When a metal reacts with hydrogen carbon dioxide gas is produced? True or False
Answer:
false
Explanation:
"When a metal reacts with hydrogen carbon dioxide gas is produced" statement is false.
What is a chemical equation?A chemical reaction is a representation of symbols of the elements to indicate the amount of substance and moles of reactant and product.
Generally, metals do not react with hydrogen. But some metals like sodium, potassium, calcium and magnesium force the hydrogen atom to accept the electrons given by these elements and form salt-like ionic solid compounds called metal hydrides.
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How many moles is 3.01 x 10 24 molecules of oxygen ( g)?
Answer:
5.00 moles O₂
General Formulas and Concepts:
Chemistry - Atomic Structure
Using Dimensional AnalysisAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Explanation:
Step 1: Define
3.01 × 10²⁴ molecules O₂
Step 2: Convert
[tex]3.01 \cdot 10^{24} \ mc \ O_2(\frac{1 \ mol \ O_2}{6.022 \cdot 10^{23} \ mc \ O_2} )[/tex] = 4.99834 moles O₂
Step 3: Check
We are given 3 sig figs. Follow sig fig rules and round.
4.99834 moles O₂ ≈ 5.00 moles O₂
Which of the following correctly identifies and explains the charge on an atom of
sodium?
Answer:
The best and most correct answer among the choices provided by your question is the fourth choice.
The data explains that sodium atoms hardly ever form 2+ ions.
I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!
Explanation:
A ballon that contains 0.75 l of gad at 25 c is cooled to - 100 c. Calculate the new volume of the baloon
Answer:
0.44L
Explanation:
Given parameters:
Initial volume = 0.75L
Initial temperature = 25°C = 273 + 25 = 298K
Final temperature = -100°C = 273 + (-100) = 173K
Unknown:
New volume of the balloon = ?
Solution:
According to Charles's law;
"the volume of a fixed mass of a gas varies directly as its absolute temperature if the pressure is constant".
Mathematically;
[tex]\frac{V_{1} }{T_{1} }[/tex] = [tex]\frac{V_{2} }{T_{2} }[/tex]
V and T are temperature values
1 and 2 are the initial and final states
Insert the parameters and solve;
[tex]\frac{0.75}{298}[/tex] = [tex]\frac{V_{2} }{173}[/tex]
298V₂ = 129.75
V₂ = 0.44L
Alcohol is a
Depressant
Muscle relaxer
Both
Alcohol is both a Depressant and a Muscle Relaxer. Therefore the answer would be both!
Hope this helps :)
Brad pushed a shopping cart directly toward his car at a constant velocity for 6.0 seconds.
During that time, Brad's daughter jogged past him at 2.4 meters per second, and the cart
moved 6.6 meters. What was the cart's velocity?
Answer:
Watch Naruto that's the answer
Explanation:
Calculate the number of moles of MgF2 that dissolved.
Moles of MgF₂ : 1.2 x 10⁻⁴
Further explanationMaybe the complete question is like this
A student prepares 100. mL of a saturated solution of MgF2 by adding 0.50 g of solid MgF2 to 100. mL of distilled water at 25°C and stirring until no more solid dissolves. (Assume that the volume of the undissolved MgF2 is negligibly small.) The saturated solution is analyzed, and it is determined that [F−] in the solution is 2.4 × 10−3 M.
The dissociation reaction of MgF₂
MgF₂(s)⇒ Mg²⁺(aq)+2F⁻(aq)
mol ratio MgF₂ : F⁻ = 1 : 2
mol of F⁻ in 100 ml solution :
[tex]\tt mol=M\times V\\\\mol=2.4\times 10^{-3}\times 0.1=2.4\times 10^{-4}[/tex]
mol MgF₂ :
[tex]\tt \dfrac{1}{2}\times 2.4\times 10^{-4}= 1.2\times 10^{-4}[/tex]
an 11.5g sample of ethonal 6.00g of Carbon 1.51g of hydrogen what is the percent composition of each element
C : 52.2%, H : 13.1%, O:34.7%
Further explanationThe empirical formula is the smallest comparison of atoms of compound forming elements.
A molecular formula is a formula that shows the number of atomic elements that make up a compound.
(empirical formula) n = molecular formula
11.5 g of Ethanol-C₂H₅OH contains 6.00 g of Carbon and 1.51 g of Hydrogen.
mass of Oxygen :
[tex]\tt 11.5-(6+1.51)=4~g[/tex]
Percent composition :
C[tex]\tt \dfrac{6}{11.5}\times 100\%=52.2\%[/tex]
H[tex]\tt \dfrac{1.51}{11.5}\times 100\%=13.1\%[/tex]
O[tex]\tt \dfrac{4}{11.5}\times 100\5=34.7\%[/tex]
What volume of a 0.181 M nitric acid solution is required to neutralize 25.1 mL of a 0.167 M calcium hydroxide solution
Answer:
46.32 mL
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
2HNO₃ + Ca(OH)₂ —> Ca(NO₃)₂ + 2H₂O
From the balanced equation above,
The following data were obtained:
Mole ratio of the acid, HNO₃ (nA) = 2
Mole ratio of the base, Ca(OH)₂ (nB) = 1
Next, we shall write out the data obtained from the question. This includes:
Molarity of the acid, HNO₃ (Ma) = 0.181 M
Volume of the base, Ca(OH)₂ (Vb) = 25.1 mL
Molarity of the base, Ca(OH)₂ (Mb) = 0.167 M
Volume of the acid, HNO₃ (Va) =?
Finally, we shall determine the volume of the acid, HNO₃ as shown below:
MaVa/ MbVb = nA/nB
0.181 × Va / 0.167 × 25.1 = 2/1
0.181 × Va / 4.1917 = 2
Cross multiply
0.181 × Va = 4.1917 × 2
0.181 × Va = 8.3834
Divide both side by 0.181
Va = 8.3834 / 0.181
Va = 46.32 mL
Therefore, the nitric acid, HNO₃ required for the reaction is 46.32 mL
Calculate the new pressure of a gas if the gas at 50 ˚C and 81.0 kPa is heated to 100 ˚C at a constant volume.
Answer:
93.5 kPa
Explanation:
Step 1: Given data
Initial pressure (P₁): 81.0 kPaInitial temperature (T₁): 50 °CFinal pressure (P₂): ?Final volume (T₂): 100 °CStep 2: Convert the temperatures to the Kelvin scale
When working with gases, we need to consider the absolute temperature. We will convert from Celsius to Kelvin using the following expression.
K = °C + 273.15
T₁: K = 50°C + 273.15 = 323 K
T₂: K = 100°C + 275.15 = 373 K
Step 3: Calculate the final pressure of the gas
At a constant volume, we can calculate the final pressure of the gas using Gay-Lussac's law.
P₁/T₁ = P₂/T₂
P₂ = P₁ × T₂/T₁
P₂ = 81.0 kPa × 373 K/323 K
P₂ = 93.5 kPa
Everything in outer space including stars, planets, and galaxies
O A. Solar System
B. Universe
OC. Galaxy
D. Biosphere
I
Answer:
Universe.
Explanation:
Biosphere is just a planet. Solar system contains planets and star. Galaxy holds multiple solar systems only. Universe hold everything, biospheres, solar systems, and galaxies. I hope this helps :D
Answer:
B.
Explanation:
A solar system is IN a galaxy. Its not A.
A Galaxy doesnt have other galaxies in it. Its not c
A biosphere is only referring to earth. its not D.
Therefore, it is B. A universe is everything in outer space including stars, planets, and galaxies.
28.The chemical formula of a compound indicates
the source of the elements in the compound.
b. how elements are joined in the compound.
the alchemy symbols for the elements in the compound.
d. the relative proportions of the elements in the compound.
Answer:
d. the relative proportions of the elements in the compound.
Explanation:
The chemical formula of a compound indicates the relative proportions of the element in the compound.
The chemical formula of a compound is a representation which shows all the elements therein and the mole relationship between them expressed as subscripts. For example HCl, contains one mole of hydrogen and 1 mole of Cl.sodium hydroxide is extremely soluble in water. a saturated solution contains 678.57 grams of sodium hydroxide 1.00 liter of solution. calculate the molarity of a saturated sodium hydroxide solution.
Answer:
M = 17 M
Explanation:
Given data:
Mass of sodium hydroxide = 678.57 g
Volume of solution = 1.00 L
Molarity of solution = ?
Solution:
Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.
Formula:
Molarity = number of moles of solute / L of solution
Number of moles of sodium hydroxide:
Number of moles = mass/molar mass
Number of moles = 678.57 g /40 g/mol
Number of moles = 17 mol
Molarity:
M = 17 mol/1.00 L
M = 17 mol/L
M = 17 M