Answer:
c-)O2
Explanation:
What types of teeth do mammals have? Select the three correct answers.
incisors
molars
gills
canines
Answer:
incisors, molars, canines.
Explanation:
All of these 3 teeth types appear in ourselves so in conclusion mammals. Plus there has never been gills in any mammal.
Which of the following correctly represents the radioactive decay of cesium-137?
A sample of methane gas that has a volume of 3.8 L at 5°C is heated to 86°C at constant pressure. Calculate its new volume.
According to the Charle's law as pressure is constant the new volume of gas is 4.907 L.
What is Charle's law?Charles law is an experimental gas law which provides description about the behavior of gases which tend to expand on heating.It states that, at constant pressure, the temperature is in direct proportion with the volume that is,V∝T or V₁/T₁=V₂/T₂.The relation between volume and temperature is linear as the temperature increases volume also increases.
The graph of volume versus temperature is a straight line passing through the origin.The law was proposed by Jacques Charles , a french physicist in 1780.
In the given problem , on substituting values in above formula, V₂=3.8×278/359=4.907 L.
Thus , the new volume of methane gas is 4.907 L.
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1. How many moles of oxygen will occupy a volume of 2. 5 liters at 1. 2 atm and 25ºC?
2. What volume will 2. 0 moles of nitrogen occupy at 720 mm Hg and 20. 0ºC?
3. What pressure will be exerted by 25 g of CO2 at a temperature of 35ºC and a volume of 500. 0 mL?
4. At what Celcius temperature will 5. 00 g of Cl2 exert a pressure of 900. 0 mm Hg at a volume of 750 mL?
(1) The number of moles of oxygen gas is 0.123 mole.
(2) The volume occupied by the nitrogen gas is 50.75 Liters.
(3) The pressure exerted by the CO2 gas is 28.7 atm
(4) The temperature of the Cl2 gas is -118.37⁰C
Number of moles of oxygenThe number of moles of oxygen occupied at the given condition is calculated as follows;
PV = nRT
n = PV/RT
where;
T = 25ºC = 273 + 25 = 298KR is ideal gas constant = 0.08205 L.atm/mol.Kn = (2.5 x 1.2) / (0.08205 x 298)
n = 0.123 mol
Volume of the gasPV = nRT
V = nRT/P
where;
R = 62.36 L.mmHg/mol.KV = (2 x 62.36 x 293) / (720)
V = 50.75 Liters
Pressure of the gasPV = nRT
P = nRT/V
where;
n is number of molesMolar mass of CO2 = 44
n = 25/44 = 0.568
P = (0.568 x 0.08205 x 308)/(0.5)
P = 28.7 atm
Temperature of the gasT = PV/nR
molar mass of Cl2 = 71 g
n = 5/71 = 0.07
T = (900 x 0.75)/(0.07 x 62.36)
T = 154.63 K
T = 154.63 - 273 = -118.37⁰C
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When an ionic compound dissolves in water, the individual ions first leave the crystal lattice and then each ion becomes surrounded by a cluster of polar water molecules. What is the sign of the entropy change for each of these two steps in the dissolving process
The entropy of the process in which the individual ions first leave the crystal lattice is positive while the entropy of the process whereby the each ion becomes surrounded by a cluster of polar water molecules is negative.
What is entropy?The term entropy has to do with the degree of disorder in a system. The higher the entropy of the system, the more the disorderliness of the system.
Now, the entropy of the process in which the individual ions first leave the crystal lattice is positive while the entropy of the process whereby the each ion becomes surrounded by a cluster of polar water molecules is negative.
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What is the mass of a sample of glass (specific heat= 0. 50 J/goC), if it requires 490 J of heat to raise the temperature from –18. 0oC to 0. 0oC?
Answer: 54 g
Explanation:
How much grams of sucrose (C12H22O11) do you need to get one kilogram of invert sugar?
Answer:
You would need 85.5 g
Explanation:
Molarity=Moles of soluteVolume of solution (in litres)0.25 M=n1 Ln = 0.25 molSo, we need 0.25 mol of sucrose to make 0.25 M solution.Molar mass of sucrose (C12H22O11)=342 g/mol Mass of 0.25 mol sucrose is0.25mol×342gmol=85.5 g
Explanation:
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50 ml of soil was mixed with 50 ml of water if the total volume of the mixture is found to be 77 ml what would be the volume of air in the soil.
PLEASE HELP ME!!!
i think the volume will be 57 , I think it will help u
What happens when a catalyst is used in a reaction?.
When a catalyst is used in a reaction then it alter the rate of the reaction.
What is catalyst?Catalyst are those species which are added on the reaction to alter the rate of the reaction without being involved in the reaction.
Catalyst are of two types:
Positive catalyst: It increases the rate of the reaction.Negative catalyst: It decreases the rate of the reaction.Hence, catalyst is used to change the rate of the reaction.
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What is the percentage of water in the following compound? answer using one decimal place. sodium carbonate decahydrate, na2co3 • 10h2o % by mass h2o
The percentage by mass of water in Na2CO3.10H2O from the calculation is 62.9%
What is percentage by mass?The term percentage by mass refers to the amount of a particular moiety by mass in a molecule.
In this case, we know that the molar mass of Na2CO3.10H2O is 286 g/mol the molar mass of the 10 moles of water is 180 g/mol hence the percentage by mass of water in the compound is; 180 g/mol /286 g/mol * 100/1 = 62.9%
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Answer:
63.0
Explanation:
got it wrong so it told me the answer
Which of the following are classified as an electron group? A.Charged atoms. B.Lone pairs of electrons. C.Ions. D.Bonded pairs of electrons
Answer:
B.) lone pairs of electronsExplanation:
The table below indicates the “Molecular Geometry” of the central atom depending on whether the groups of electrons around it are covalent bonds to other atoms or simply lone pairs of electrons.
what is magnetism?explain any three evidence that support terrestrial magnetism.
Answer:
Magnetism is the force exerted by magnets when they attract or repel each other.
For Evidence of terrestrial magnetism
When a magnetic body is buried inside the earth in a North-South direction, it gets magnetized due to the effect of terrestrial magnetism. A freely suspended magnet faces a North-South direction
Explanation:
The reason why magnetism acts this way is caused by the motion of electric charges. Every substance is made of tiny units called atoms. Each atom contains electrons, particles that carry electric charges.
I really hope this helps you.
Some greenhouse gases, such as fluorocarbons (CFCs, HFCs, PFCs, etc.), are human-made. Others, such as water, methane, and carbon dioxide, are naturally produced. Which type of greenhouse gas (human-made or natural) is more difficult to control and eliminate?
Which types are easier? In three to five sentences, provide evidence for your argument.
Wetlands are able to remove nutrients and chemicals from water as the water flows through the area. A developer is planning to destroy most of the wetlands near a bay. In three to five sentences, explain how destroying the wetlands would impact the bay’s water quality and ecosystem.
Carbon dioxide (CO2) is the hardest human-made greenhouse gas to control because it is released with cellular respiration.
What are greenhouse gases?Greenhouse gases are gases that trap solar radiation and increase the temperature on the Earth's surface.
The easier human-made greenhouse gases to control are chlorofluorocarbons because they can be substituted in the industry by other materials.
The destruction of the wetlands would impact the bay’s water quality and ecosystem because these areas contain pure water required for the whole ecosystem.
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Giving BRAINLIEST, please HELP!
Answer:
C
Explanation:
a and b represent ice and melting respectively
You need to make an aqueous solution of 0.173 M zinc fluoride for an experiment in lab, using a 500 mL volumetric flask. How much solid zinc fluoride should you add
Answer:
About 8.94.
Explanation:
Because we are given a 500. mL volumetric flask, the solution will have a volume of 500. mL.
Find the number of moles of zinc fluoride needed. Recall that molarity is simply moles per liter of solution:
[tex]\displaystyle 500.\text{ mL} \cdot \frac{0.173\text{ mol ZnF$_2$}}{1\text{ L}} \cdot \frac{1\text{ L}}{1000\text{ mL}} = 0.0865\text{ mol ZnF$_2$}[/tex]
Convert this to grams. The molecular weight of zinc fluoride is 103.38 g/mol:
[tex]\displaystyle 0.0865\text{ mol ZnF$_2$} \cdot \frac{103.38\text{ g ZnF$_2$}}{1\text{ mol ZnF$_2$}} = 8.94\text{ g ZnF$_2$}[/tex]
In conclusion, about 8.94 grams of solid zinc fluoride should be added.
What are the reactants in copper wire added to silver nitrate?
Answer:
Silver nitrate (AgNO3) reacts with copper (Cu) to form copper(II) nitrate (Cu(NO3)2) and silver (Ag). This can be called a redox reaction because silver nitrate is reduced and copper is oxidized
Calculate the molarity of 6.631 g NANO3 in 100.0 mL of solution
add stepss
Answer:
0.7802 M
Explanation:
Data:
V (volume) = 100.0 mL → V = 0.1000 Lm (mass) = 6.631 g → n = 0.07802 molWanted:
M (Molarity)Equation:
M = [tex]\frac{mol}{L}[/tex]
Solution:
1. Convert mL to L:
V = 100.0 mL x [tex]\frac{1 L}{1000 mL}[/tex] = 0.1000 L2. Convert g to mol:
n = [tex]\frac{6.631 g}{84.9947 g/mol}[/tex] = 0.07802 mol3. Molarity Equation:
M = [tex]\frac{0.07802 mol}{0.1000 L}[/tex] = 0.7802 MAnswer:
Explanation:
Mole weight of NaNO3 ====> ~~ 85 gm
6.631 / 85 = # moles in .1 liter
6.631/85 / (.1) = .78 M
Why can’t you see the stars very well at night like you could 50 years ago
Answer:Artificial light from cities has created a permanent "skyglow" at night, obscuring our view of the stars. Here's their map of artificial sky brightness in North America, represented as a ratio of "natural" nighttime sky brightness. In the black areas, the natural night sky is still (mostly) visible.
Explanation:
ACELLUS LAB-ACID BASE TITRATION
a student overshot the equivalence point when he was using NaOh to determine the concentration of an unknown acid, HA. What ions are present in the purple solution in the flask?
Answer: A-, NA+ And OH-
Explanation: Thank me later
Please answer these. It's part of Quantitave Chemistry. Calculating limiting raegents
The limiting reactant refers to the reactant that is in small amount. The extent of the reaction depends on the amount of the limiting reactant.
What is limiting reactant?The term limiting reactant refers to the reactant that is in small amount, We shall now solve the questions individually.
1) The reaction equation is;
CaO + H2O → Ca(OH)2
Number of moles of CaO = 10 g/56 g/mol = 0.18 moles
Number of moles of H2O = 10 g/18 g/mol = 0.56
Since the reaction is 1:1, CaO is the limiting reactant
Mass of calcium hydroxide = 0.18 moles * 74 g/mol = 13.32 g
2) The reaction equation is;
Mg + Br2 → MgBr2
Number of moles of Mg = 1 g/24 g/mol = 0.042 moles
Number of moles of Br2= 5 g/160 g/mol = 0.031 moles
Since the reaction is 1:1, Br2 is the limiting reactant
Mass of MgBr2 = 0.031 moles * 184 g/mol = 5.7 g
3) The reaction equation is;
CuO + H2 → Cu + H2O
Number of moles of CuO= 2.00 g/80 g/mol = 0.025 moles
Number of moles of H2 = 1.00g/2 g/mol = 0.5 moles
Since the reaction is 1:1, CuO is the limiting reactant
Mass of Cu = 0.025 moles * 63.5 g/mol = 1.59 g
4) The reaction equation is;
2Na + F2 → 2NaF
Number of moles of Na = 2.30 g/23 g/mol = 0.10 moles
Number of moles of F2 = 2.85 g/38 g/mol = 0.075 moles
If 2 moles of Na react with 1 mole of F2
x moles of Na reacts with 0.075 moles of F2
x = 0.15
Hence Na is the limiting reactant
Mass of NaF = 0.10 moles * 42 g/mol = 4.2 g
5) The equation of the reaction is;
Fe2O3 + 2Al → 2Fe + Al2O3
Number of moles of Fe2O3 = 8.00 g/160 g/mol = 0.05 moles
Number of moles of Al = 2.16 g/27 g/mol = 0.08 moles
If 1 mole of Fe2O3 reacts with 2 mole of Al
x moles of Fe2O3 reacts with 0.08 moles of Al
x = 0.04 moles
Hence, Fe2O3 is the limiting reactant
1 mole of Fe2O3 yileds 2 moles of Fe
0.05 moles yileds 0.05 moles * 2 moles/1 mole = 0.1 moles
Mass of Fe = 0.1 moles * 56 g/mol = 5.6 g
6) The equation of the reaction is;
2Al + 3Cl2 → 2AlCl3
Number of moles of Al = 13.5 g/27 g/mol = 0.5 moles
Num ber of moles of Cl2 = 42.6 g /71 g/mol = 0.6 moles
If 2 moles of Al reacts with 3 moles of Cl2
x moles of Al reacts with 0.6 moles of Cl2
x = 0.4 moles
Al is the limiting reactant
Mass of AlCl3 = 0.4 moles * 133 g/mol = 53.2 g
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What is the molecular formula of a compound with an empirical formula of ch and a molar mass of 78. 1 g/mol?.
Answer:
answer is in the explanation
Explanation:
Answer. Explanation: ->So, molecular formula = (CH)n = (CH)6 =C6H6; in this case we substituted the calculated value of n. ->Therefore, the molecular formula of the compound having the molecular weight 78 g/mol is (D) - C6H6.
create a list of at least 5 reasons to avoid alcohol during adolescence.
People who are younger are usually at greater risk of alcohol related harm at a younger age. the younger you are when you drink alcohol, it can lead to you developing damage in your brain as well as problems later in life. drinking at a young age can lead to things like an inability to learn, problems with verbal skills, being dependent on alcohol, and depression.
Hypobromous acid (HOBr) is produced in the blood and has properties that combat pathogens. It is also used in bleaches and other cleaning products. The following is a reversible reaction:
HOBr → H+ + OBr–
a. Write the equation you would use to calculate the Ka of this reaction.
b. If [H+] at equilibrium is 9. 1 × 10–6, what is the Ka of the reaction, given a final HOBr concentration
of 0. 33 M?
From the calculations in the question, we have that the dissociation constant is 2.5 * 10^-10.
What is Ka?The term Ka has to do with the acid dissociation constant and it is obtained from; Ka = [H+] [OBr–]/[HOBr]
Now, we are told that the hydrogen ion concentration at equilibrium is 9. 1 × 10–6 and the HOBr concentration is 0.33 M, it the follows that;
Ka = (9. 1 × 10–6)^2/ 0.33
Ka = 2.5 * 10^-10
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Why do the stars appear to move across the night sky?
Answer:
The stars arent moving, we are.
Explanation:
The rotational movement of the Earth is what makes the star appear as if moving from the east to the west in the sky, as the planet rotates with an axis pointed towards the direction of our/the North Star.
What is the molecular geometry, or shape, of phosphorus trichloride (PCl3)?
Answer:
trigonal pyramidal
Explanation:
Looking at the PCl3 molecular geometry it is trigonal pyramidal with a bond angle of approx. 103o. The is mainly due to the disproportionate influence or greater repulsion of the phosphorus lone pair which makes it deviate from the ideal angle of 109o.
Answer:
I believe the molecular geometry of PCL3 would be trigonal planar.
Explanation:
Why are intermolecular forces generally much weaker than bonding forces?.
Explanation:
Intermolecular forces: These are the attractive or repulsive forces acting between two molecule in interaction.
The attractive forces between molecules are of several types based on the interaction between molecules also known as Vander wall forces.
Bonding forces: They are also attractive forces acting between two constituents (atom, ion, radicals etc) and stabilizes the constituent particles by loss of energy. The bond between any two species are formed by the overlapping of corresponding orbitals.
Whenever positive overlapping occurs between species, the formation of Bonding molecular orbital (BMO) takes place. and when electron enters into BMO it loses energy. Alternative form of explaining the concept is Individual electron possess more energy than the electrons that paired or Bonded.
Now coming to your question,
All the intermolecular forces are formed by weak attractive forces (vanderwall forces) which includes Ion-dipole forces, Ion-induced-dipole forces, Dipole-dipole forces, Dipole-induced-dipole forces, Hydrogen bonds & London forces.
All these forces are temporary and weak, and formed by the poles generated on molecule due to shift of electron, for e.g. Any molecule having more electron at one pole and less electron at another pole then that molecule start acting as charged body when that charged body comes in contact with opposite pole of another charged body the interaction takes place, since the electrons are dynamic and unsteady it's not possible that the pole will keep acting same as before. hence the intermolecular forces are generally weaker.
On the other side the Bonding electrons, are formed by the various strong overlapping such as between Head to Head overlapping leads to formation of Sigma bond which is the strongest bond takes alot of Energy to break & Lateral overlapping lead to formation of pi bond which is also stronger bond than that of Hydrogen bond.
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How do you calculate the change in free energy for a reaction under nonstandard conditions?.
We can calculate the change in free energy for a reaction under nonstandard conditions by using the ΔG = ΔH - TΔS equation.
How do we calculate chnage in free energy?Change in gibbs free energy of any reaction will be calculated by uisng the below equation as:
ΔG = ΔH - TΔS, where
ΔH = change in enthalpy
T = temperature of reaction
ΔS = chnage in entropy
By putting all given values we can calculate the gibbs free energy of the reaction, and negative sign of energy shows the spontaneity of the reaction.
Hence by using the enthalpy, entropy and temperature we can calculate the free energy change.
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A solution contains 90 grams of a salt dissolved in 100 grams of of water at 10C. The solution could be an unsaturated solution of
Answer: Potassium iodide
Explanation:
What volume of a 2.60 M HCl solution should you use to prepare 2.80 L of a 0.200 M HCl solution
Answer:
0.215 L HCl
Explanation:
Using the relationship (M1 x V1 = M2 x V2) between Molarity (M) and Volume (v or L), we can find the volume of the 2nd volume amount.
First we rearrange our relationship equation to: [tex]V_2 = \frac{M_1 * V_1 }{M_2}[/tex]
Now, plug in the values. [tex]V_2 = \frac{0.2 * 2.8}{2.6}[/tex]
Calculating these values, we end up with the answer:
0.215 L HCl
What is the empirical formula of a compound that is 41.4% Strontium, 13.24%
Nitrogen, and 45.3696 Oxygen ?
Answer:
Empirical Formula N2O6Sr Strontium Nitrate
Explanation:
N=13.2% O=45.4% Sr=41.4%