Answer:
16.0 g/mol (3 s.f.)
Explanation:
Molar mass is the mass of a mole of substance.
1 mole of CH₄ has 1 C atom and 4 H atoms.
Since the molar mass is numerically equal to the molecular mass of a compound, let's find the molecular mass of CH₄ first.
Molecular mass= sum of all the atomic mass in a molecule
Molecular mass of CH₄
= 12.011 amu +4(1.008 amu)
= 16.043 amu
Thus the molar mass of CH₄ is 16.043g/mol, or 16.0g/mol to 3 significant figures.
A solution is prepared by adding 0.0231moles of H3O+ ions to 3.33L of water. What is the pH of this solution
Answer:
2.15
Explanation:
For this question, we have to remember the pH formula:
[tex]pH~=~-Log[H_3O^+][/tex]
By definition, the pH value is calculated when we do the -Log of the concentration of the hydronium ions ([tex]H_3O^+[/tex]). So, the next step is the calculation of the concentration of the hydronium ions. For this, we have to use the molarity formula:
[tex]M=\frac{mol}{L}[/tex]
We already know the number of moles (0.0231 moles) and the volume (3.33 L). So, we can plug the values into the molarity formula:
[tex]M=\frac{0.0231~moles}{3.33~L}=0.00693~M[/tex]
With this value, now we can calculate the pH value:
[tex]pH~=~-Log[0.00693~M]~=~2.15[/tex]
The pH would be 2.15
I hope it helps!
Heavy nuclides with too few neutrons to be in the band of stability are most likely to decay by what mode?
Answer:
Positron emission
Explanation:
Positron emission involves the conversion of a proton to a neutron. This process increases the mass number of the daughter nucleus by 1 while its atomic number remains the same. The new neutron increases the number of neutrons present in the daughter nucleus hence the process increases the N/P ratio.
A positron is usually ejected in the process together with an anti-neutrino to balance the spins.
Sort the following gases by whether they are transparent to incoming short-wavelength UV radiation or whether they absorb longer wavelength terrestrial re-radiation.
O2
N2
CH4
H2O
CO2
Ar
Categories
Absorb No Radiation Absorb Re-Radiation
Answer:
Short wavelength UV radiation ----Oxygen (O2 ), nitrogen (N2) , methane (CH4) , water (H2O) and carbondioxide (CO2).
longer wavelength radiation---- methane (CH4) , water (H2O) and carbondioxide (CO2)
Explanation:
Oxygen (O2 ), nitrogen (N2) , methane (CH4) , water (H2O) and carbondioxide (CO2) are the gases which are transparent for incoming short-wavelength UV radiation while methane (CH4) , water (H2O) and carbondioxide (CO2) are the greenhouse gases which absorb longer wavelength. When the solar radiation comes to the earth, it has short wavelength but after reflection it converts into longer wavelength which can be prevent by greenhouse gases and increases the temperature of atmosphere.
CH4, H2O and CO2 gases absorb longer wavelength terrestrial re-radiation.
UV radiation are short wavelength radiation that reach the earth from outer space. However, certain gases that compose the atmosphere are able to absorb longer wavelength terrestrial re-radiation.
The following gases absorb longer wavelength terrestrial re-radiation;
CH4H2OCO2The following gases are transparent to incoming short-wavelength UV radiation;
O2N2ArLearn more: https://brainly.com/question/6284546
Consider the reaction when aqueous solutions of potassium hydroxide and ammonium nitrate are combined. The net ionic equation for this reaction is:
Answer: [tex]OH^-(aq)+NH_4^+(aq)\rightarrow NH_3(g)+H_2O(l)[/tex]
Explanation:
A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
[tex]KOH(aq)+NH_4NO_3(aq)\rightarrow KNO_3(aq)+NH_3(g)+H_2O(l)[/tex]
The equation can be written in terms of ions as:
[tex]K^+(aq)+OH^-(aq)+NH_4^+(aq)+NO_3^-(aq)\rightarrow K^+(aq)+NO_3^-(aq)+NH_3(g)+H_2O(l)[/tex]
Spectator ions are defined as the ions which does not get involved in a chemical equation or they are ions which are found on both the sides of the chemical reaction present in ionic form.
The ions which are present on both the sides of the equation are potassium and nitrate ions and hence are not involved in net ionic equation.
Hence, the net ionic equation is :
[tex]OH^-(aq)+NH_4^+(aq)\rightarrow NH_3(g)+H_2O(l)[/tex]
how many molecule of carbon dioxide are needed to react with excess iron oxide to produce 11.6 g of iron
Answer:
0.16 moles of Carbon
Explanation:
The balanced reaction equation:
[tex]2Fe_{2}O_{3}[/tex] + [tex]3C[/tex] → [tex]4Fe[/tex] + [tex]3CO_{2}[/tex]↑
The mole ratio of Carbon to Iron is 3 : 4 (since Fe2O3 is in excess)
i.e 3 moles of C produces 4 moles of Fe.
If 1 mole of Fe - 55.8g of Fe
? moles - 11.6g of Fe
= [tex]\frac{11.6}{55.8}[/tex] = 0.208 moles
But 3 moles of C - 4 moles of Fe
? moles of C - 0.208 moles of Fe
= [tex]\frac{3 *0.208}{4}[/tex] = 0.16 moles of carbon.
I hope this explanation was clear and useful.
Which of the following definitions best describes the term "vapor pressure?a. Pressure and temperature values on a phase diagram where two phases of a substance coexist. b. In equilibrium with the liquid phase, the pressure exerted by a gas. c. Aspecific temperature and pressure at which the liquid and gas phases of a substance have the same density and are indistinguishable from each other. d. The temperature and pressure at which all three phases of a substance coexist. Under these conditions, freezing and melting, boiling and liquefaction, and sublimation and deposition all proceed at the same rate. e. The temperature at which the vapor pressure of a liquid equals 1 atm.
Answer:
b. In equilibrium with the liquid phase, the pressure exerted by a gas.
Explanation:
When a liquid is warmed up to a temperature , it starts vaporising . The liquid is turning into gas and gas is turning into liquid at different rates . Initially the rate of former is higher but gradually the difference of rate between them decreases to zero . At this point the rate of conversion of liquid into gas and rate of conversion of gas into liquid becomes equal . This is called dynamic equilibrium point .
If we change the temperature , the equilibrium gets disturbed .
At this point the pressure exerted by the gas is called the vapour pressure of the liquid .
So option b ) is correct .
At the equilibrium point, the pressure exerted by the gas molecules to the liquid molecules has been termed the Vapor pressure. Thus, statement b is correct.
The vaporization has been the process of conversion of liquid to the gaseous state with the rise in temperature. The liquids attaining a certain temperature have been vaporized into the gaseous state.
Initially, the gas phase has been less in concentration, thus the rate of formation of gas has been greater.
After a certain amount of time, the gas phase starts to cool down and converts to the liquid state. The rate of formation of the liquid has been slower.
The time when the rate of formation of liquid, and the rate of formation of gas has been equal is termed as the equilibrium point. At the equilibrium point, the pressure exerted by the gas molecules to the liquid molecules has been termed the Vapor pressure.
Thus, statement b is correct.
For more information about the Vapor pressure, refer to the link:
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Solid sodium reacts with liquid water to form hydrogen gas according to the equation 2 Na(s) + 2 H₂O(l) → 2 NaOH(aq) + H₂(g) What is the pressure of hydrogen gas in the 20.0 L headspace of a reactor vessel when 3.34 kg sodium is reacted with excess water at 50.0°C?
Answer:
96.2 atm
Explanation:
Step 1: Write the balanced equation
2 Na(s) + 2 H₂O(l) → 2 NaOH(aq) + H₂(g)
Step 2: Calculate the moles corresponding to 3.34 kg of sodium
The molar mass of Na is 22.99 g/mol.
[tex]3.34 \times 10^{3} g \times \frac{1mol}{22.99g} =145mol[/tex]
Step 3: Calculate the moles of hydrogen formed from 145 moles of sodium
The molar ratio of Na to H₂ is 2:1. The moles of H₂ formed are 1/2 × 145 mol = 72.5 mol
Step 4: Convert the temperature to the Kelvin scale
K = °C + 273.15 = 50.0°C + 273.15 = 323.2 K
Step 5: Calculate the pressure exerted by the hydrogen gas
We will use the ideal gas equation.
[tex]P \times V = n \times R \times T\\P = \frac{n \times R \times T}{V} = \frac{72.5mol \times 0.0821atm.L/mol.K \times 323.2K}{20.0L} = 96.2 atm[/tex]
Glade air freshener gel “disappearing” is an example of
Answer:
Vaporization
Explanation:
Vaporization is the change of a specie to the gaseous state. To 'disappear' in this case simply means to change to the gaseous state.
Substances with high vapour pressure tend to be easily converted to vapour phase. Hence if Glade air freshener gel 'disappears' easily, then it has a high vapour pressure and is easily converted to vapour (gas).
consider a 1000-ml graduated cylinder with marks every 100 ml. a student records the volume of liquid in the cylinder as 750 ml. is this the correct measurement? explain
Answer:
Yes, given statement is true.
Explanation:
Given that a cylinder of 1000 ml is marked at every 100 ml.
During the test, the student can easily check the volume of liquid so the student's guess is 750 ml true.
With this measurement, we can estimate that 1/10th of 100 ml can be measured.
So, given statement is correct.
Answer:
Yes, the digit in the hundreds place is certain and the digit in the tens place is estimated.
Explanation:
Is solar radiation a natural force or a human effect?
Answer:
i think its natural . it is the natural process
Answer:
Solar radiation falls into the category of natural forces.
Explanation:
Natural forces don’t have a strong effect on recent global temperatures. The natural forces line begins to drop around 1950 and does not track with the observed temperature line. On the other hand, the human effects line rises upward with the observed temperatures, so it’s a stronger effect.
Brainilest?
Two function of mass spectrometry
Your question has been heard loud and clear.
Specific applications of mass spectrometry include drug testing and discovery, food contamination detection, pesticide residue analysis, isotope ratio determination, protein identification, and carbon dating.
Thank you
The primary function of mass spectrometry is as a tool for chemical analyses based on detection and quantification of ions according to their mass-to-charge ratio. However, mass spectrometry also shows promise for material synthesis.
tbh google
✌️
Draw the Lewis structure for the polyatomic trisulfide anion. Be sure to include all resonance structures that satisfy the octet rule.
Answer:
Explanation:
The objective here is to draw the Lewis structure for the polyatomic trisulfide anion and to be sure all resonance structures that satisfy the octet rule are included.
The Lewis structure for Polyatomic trisulfide anion
The first step is to the layout the skeleton of the Polyatomic trisulfide anion
S S S
However, the next step is to make sure we fill in the bonding pairs of electrons on the central atom.
Then , we move over to filling the lone pairs electrons before we finally have the Lewis structure for Polyatomic trisulfide anion as shown in the image below.
How many grams of gold are there in 0.353 moles of gold?
Answer: Approximately 69.5 grams of gold (Au).
Explanation:
mol = mass / molar mass
We are already given the moles of gold, 0.353. Looking at a periodic table, we cna bserve that the approximate molar mass of gold is 196.97 (I got this from ptable.com).
Plugging this into the formula above, it will look like this:
0.353 mol Au = mass / (196.97 g/mol) (in any science class, do not forget about writing your units)
To get mass by itself, multiply both sides of the equation by 196.97 g/mol.
This yields that the mass is equal to 69.5 grams. As you can see, the units of "mol" cancel out: 0.353 mol AU * (196.97 g/mol)
The reason why I rounded my answer to 69.5 grams instead of, let's say, 69.5304, is because of a concept in science referred to as significant figures. In this case, the amount of significant figures we need to round our answer to is seen in the provided value in the problem. 0.353 has only three significant figures so I have rounded the final answer to three significant figures.
Remember, do not forget to not only unclude e units that answer should be in but some teachers also request that you write the symbol of the elemnt you are writing about, so I would write my answer as: 69.5 g Au.
I hope this helps :) have a nice day!
The mass of a solid substance is 21.112 g. If the volume of the solid substance is 19.5 cm3, calculate the density of the substance (in g/cm3) with the correct number of significant digits. The density is g/cm3.
Answer:
ρ = 1.08 g/cm³
Explanation:
Step 1: Given data
Mass of the substance (m): 21.112 g
Volume of the substance (V): 19.5 cm³
Step 2: Calculate the density of the substance
The density (ρ) of a substance is equal to its mass divided by its volume.
ρ = m / V
ρ = 21.112 g / 19.5 cm³
ρ = 1.08 g/cm³
The density of the substance is 1.08 g/cm³.
40.002 g : 13.000005 g =
how many moles of MgO are produced when .250 mol of Mg reacts completely with O2
Answer:
0.250 moles of MgO are produced when 0.250 mol of Mg reacts completely with O₂
Explanation:
In first place, the balanced reaction between Mg and O₂ is:
2 Mg + O₂ ⇒ 2 MgO
By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of reactants and products participate in the reaction:
Mg: 2 molesO₂: 1 moleMgO: 2 molesThen you can apply the following rule of three: if by reaction stoichiometry 2 moles of Mg produce 2 moles of MgO, 0.250 moles of Mg, how many moles of MgO will they form?
[tex]moles of MgO=\frac{0.250 moles of Mg*2 moles of MgO}{2 moles of Mg}[/tex]
moles of MgO= 0.250
0.250 moles of MgO are produced when 0.250 mol of Mg reacts completely with O₂
The specific heat of aluminum is 0.0215 cal/g°C. If a 4.55 g sample of aluminum absorbs 2.55 cal of energy, by how much will the temperature of the sample change?
Answer:
The change in temperature is [tex]26.06^{\circ} C[/tex].
Explanation:
It is given that,
The specific heat of Aluminium is cal/g°C
Mass of the sample, m = 4.55 g
Heat absorbed, Q = 2.55 cal
We need to find the change in temperature of the sample. The heat absorbed by an object is given by :
[tex]Q=mc\Delta T[/tex]
[tex]\Delta T[/tex] is the change in temperature
So,
[tex]\Delta T=\dfrac{Q}{mc}\\\\\Delta T=\dfrac{2.55\ cal}{4.55\ g\times 0.0215 \ cal/g^{\circ} C}\\\\\Delta T=26.06^{\circ} C[/tex]
So, the change in temperature is [tex]26.06^{\circ} C[/tex].
The reaction between ammonia and oxygen is given below:
2NH3(g) + 2O2(g) → N2O(g) + 3H2O(l)
We therefore know that which of the following reactions can also occur?
a. 4 NH3(g) + 5 O2(g) --------------> 4 NO(g) + 6 H2O(g)
b. 4 NO(g) + 6 H2O(g)---------------> 4 NH3(g) + 5 O2(g)
c. N2O(g) + 3 H2O(l) ---------------> 2 NH3(g) + 2 O2(g)
d. None of the Above
Answer:
N2O(g) + 3 H2O(l) ---------------> 2 NH3(g) + 2 O2(g)
Explanation:
If we look at the reaction stated in the question, we will notice that the option chosen in the answer is the reverse of that reaction.
One thing is clear, if a reaction is possible, then its reverse reaction is equally possible. The equilibrium position may shift towards the forward or reverse reaction based on the conditions of the reaction.
Hence if the reaction, 2NH3(g) + 2O2(g) → N2O(g) + 3H2O(l) is possible, then the reaction, N2O(g) + 3 H2O(l) ---------------> 2 NH3(g) + 2 O2(g) is also possible.
What are metals that have been mixed together called
Answer:
Alloys
I hope this helps!
Answer:
D.An alloy
Explanation:
Nuclear binding energies for the fusion of a mole of nuclei typically correspond to mass differences on the order of:
A. grams
B. milligrams
C. micrograms
D. nanograms
Answer:
nanograms
Explanation:
Nuclear binding energy refers to the energy needed in order to break up the nucleus of an atom into its component parts: protons and neutrons, it is also the energy used up in the formation of the atom.
The difference between the calculated and actual mass of a nucleus gives its mass defect which is used to calculate the binding energy according to Einstein's equation. The mass differences are usually very small, as little as the order of nanograms.
Students set up a controlled experiment. They put five
crickets in each of three identical containers. They set one
container to 15°C, one to 20°C, and one to 25°C. Then they
count the number of cricket chirps in each container
during 1 hour
What are two constants in this experiment?
A. The number of crickets in each container
B. The number of cricket chirps
O C. The kind of containers used
D. The temperature of each container
The experimental design includes the controlled, independent, and dependent variables. The number of crickets and kinds of containers is two constant. Thus, options A and C are correct.
What are control variables?Control variables are the experimental element that remains fixed and unchanged in an experimental setup. They are constant and not are directly related to the interest of the investigation topic but are known to influence the results and observations.
The control variables can influence the dependent variable of the experiment as the number of crickets in each container and the type of container can indirectly alter the outcome and the conclusion of the experiment. The number of cricket will influence the effect of the temperature and the type of container can alter the survival rate.
Therefore, in options A and C. the number of cricket and container are two constants.
Learn more about variables, here:
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A scientist wants to use a model to help present the results of his detailed scientific investigation.
Why would a model be useful?
because the model makes the concepts easier to understand
because the model is easy to put together and to use
because the model prevents other scientists from asking questions
Obecause the model requires the audience to pay full attention to it
Answer:
Because the model makes the concepts easier to understand
Explanation:
Models are created to give a visual of every aspect of an experiment. This allows for a better understanding across the board for everyone.
At elevated temperatures, dinitrogen pentoxide decomposes to nitrogen dioxide and oxygen:_________.
2N2O5(g)→4NO2(g)+O2(g)
When the rate of formation of O2 is 8.1 x 10^−4 M/s, the rate of decomposition of N2O5 is _____ M/s.
a. 3.2 x 10^−3
b. 8.1 x 10^−4
c. 1.6 x 10^−3
d. 2.0 x 10^−4
e. 4.1 x 10^−4
Answer:
e. 4.1 x 10^−4
Explanation:
For the reaction;
2N2O5(g) → 4NO2(g) + O2(g)
The rate of formation is given as;
(1 / 4) Δ [O2] / Δt = (1 / 2 )Δ [N2O5] / Δt
Δ [O2] / Δt = 8.1 x 10^−4 M/s
Inserting into he equation, we have;
(1/4) (8.1 x 10^−4 ) = (1/2) (Δ [N2O5] / Δt)
2.025 x 10^−4 = (1/2) (Δ [N2O5] / Δt)
Δ [N2O5] / Δt = 2 * 2.025 x 10^−4
Δ [N2O5] / Δt = 4.1 x 10^−4
Correct option is option E.
Decide which element probably has a melting point most and least similar to the melting point of cesium
The question is incomplete, so the complete question is as follows:
Decide which element probably has a melting point most and least similar to the melting point of cesium. Comparing melting point: helium thallium sodium strontium
Answer:
Most similar melting point : Sodium
Least similar melting point: Strontium
Explanation:
Melting point is defined as the temperature at which soid will melt or get converted into liquid.
Melting point of cesium is 28.44 °C and most similar melting point is sodium as its melting point is 97.72°C and least similar melting point is strontium as it has melting point 777°C.
Hence, the correct answer is:
Most similar melting point : Sodium
Least similar melting point: Strontium
What family on the periodic table has ad least one solid, one liquid and one gas.
Answer:
FLUORINE, CHLORINE, BROMINE, IODINE, ASTATILE AND TENNESINE
Explanation :
Florine and chorine=gas
Bromine=liquid
ASTATILE and TENNESINE =solid
HOPE IT is right
Convert
propene n to propane
⬇️
Explanation:
First convert propane to chloropropane by halogenation reaction in presence of sunlight
CH3-CH2-CH3 + Cl2 → CH3-CH2-CH2Cl + HCl
Chloropropane can be converted into propene by using alcoholic KOH
CH3-CH2-CH2Cl + alc. KOH → CH3-CH=CH2
To convert from Propene to Propan-2-ol, the addition of H2SO4 takes place in accordance with Markovnikov ‘s rule i.e.
The molar solubility of a slightly soluble ionic compound M2X3 is 2.8 x 10-6 M. Determine the value of Ksp.
Answer:
1.9 × 10⁻²⁶
Explanation:
Step 1: Write the solution reaction for M₂X₃
M₂X₃(s) ⇄ 2 M³⁺(aq) + 3 X²⁻(aq)
Step 2: Make an ICE chart
We can relate the molar solubility (S) with the solubility product constant (Ksp) using an ICE chart.
M₂X₃(s) ⇄ 2 M³⁺(aq) + 3 X²⁻(aq)
I 0 0
C +2S +3S
E 2S 3S
The solubility product constant is:
Ksp = [M³⁺]² × [X²⁻]³ = (2S)² × (3S)³ = 108 S⁵ = 108 (2.8 × 10⁻⁶)⁵ = 1.9 × 10⁻²⁶
The value of Ksp when there is the slightly soluble ionic compound so it should be 1.9 × 10⁻²⁶.
Calculation of the value of ksp:Since the solution reaction for M₂X₃ should be
M₂X₃(s) ⇄ 2 M³⁺(aq) + 3 X²⁻(aq)
Now make an ICE chart
So it can be like
M₂X₃(s) ⇄ 2 M³⁺(aq) + 3 X²⁻(aq)
I 0 0
C +2S +3S
E 2S 3S
Now The solubility product constant is:
Ksp = [M³⁺]² × [X²⁻]³
= (2S)² × (3S)³ = 108 S⁵
= 108 (2.8 × 10⁻⁶)⁵
= 1.9 × 10⁻²⁶
hence, The value of Ksp when there is the slightly soluble ionic compound so it should be 1.9 × 10⁻²⁶.
Learn more about molar here: https://brainly.com/question/19004694
The number of possible monobromination products, including cis-trans isomers, of methylcyclopentane is:________
A) 2
B) 3
C) 4
D) 5
E) 6
Answer:
D) 5
Explanation:
In this case, the "monobromination" is the addition of one "Br" to the molecule. With this in mind, we have to explore each option to put this "Br" atom:
1) (bromomethyl)cyclopentane = The Br atom is placed in carbon 6
2) 1-bromo-1-methylcyclopentane = The Br atom is placed in carbon 1
3) (1R,2R)-1-bromo-2-methylcyclopentane = The Br atom is placed in carbon 2 (with trans configuration)
4) (1R,2S)-1-bromo-2-methylcyclopentane = The Br atom is placed in carbon 2 (with cis configuration)
5) 1-bromo-3-methylcyclopentane = The Br atom is placed in carbon 3
See figure 1
I hope it helps!
A
Identify the exact numbers.
2.54 cm (the number of centimeters in exactly 1 in)
4 choices (the number of choices in this list)
56.00 s (a time measured by a stopwatch)
3 lbs (the weight of an object measured on a scale)
Answer:
the answer is (2.54cm in an inch, and 4 number of choices in this question)
Explanation:
An exact number is not rounded, and cannot be changed such as placing a different item on the scale it would change.
What determines an atom's identity? Question 1 options: Atomic Mass Element Name Number of Protons Number of Neutrons