Answer:
Bohr
Explanation:
Neils Bohr was the scientist that suggested that electrons follow predictable orbits round the nucleus.
In 1913, he put forward his own model of the atom based on the quantum mechanics originally developed by Planck. He assumed the Rutherford's model and suggested that the extranuclear part consists of electrons in specific spherical orbits around the nucleus. The orbits/energy levels are designated as K, L, M, N.....Answer:
schrodinger
Explanation:
jelly benee
What is the number of atoms in 2.65g of CH 4
Answer:
9.936x10^22 atoms of CH4
Explanation:
grams ----> mol
2.65 g CH4 if 1 mol of CH4 = 16.04 g CH4
2.65/16.04 = 0.165 mol of CH4
mol ------> atoms
1 mol = 6.022 x 10^23 atoms
0.165 mol x 6.022x10^23 = 9.936x10^22 atoms of CH4
Susan has just moved into a new house. For some reason, she cannot get the grass to grow in her yard. She decided to grow small amounts of grass inside her house as part of an experiment. The first group of grass is exposed to light intensity of 400. The second group is exposed to light intensity of 1200. The graph below shows the results of Susan's experiment. 11. According to the graph, which of the following should be expected from Susan's two groups of plants?
A. The plants at a light intensity of 1200 will produce more oxygen than the plants at 400.
B. The plants at a light intensity of 1200 will perform only stage 1 of photosynthesis.
C. The plants at light intensity of 400 will produce more glucose than the plants at 1200.
D. The plants at a light intensity of 400 will grow more quickly than the plants at 1200.
Please help guys this is due tomorrow
Answer:
A
Explanation:
How do you make a substance that glows in the dark? (for example glowsticks)
Answer:
Pour fluorescent dye and phenyl oxalate ester solution into the glass beaker with the hydrogen peroxide. Once the two solutions are combined, a chemical reaction will take place and cause the fluid to glow in the dark.
NaBH4 is typically used in excess. Since the rate law for reduction of an aldehyde is first order in both NaBH4 and in aldehyde, how will using excess NaBH4 affect the overall reaction rate
Answer:
As the amount of NaBH4 is increased, the overall reaction rate also increases
Explanation:
This question tells us that NaBH4 is typically used in excess.
the rate law for reduction of an aldehyde is first order in NaBH4 and also in aldehyde,
We have The rate of reaction to be the equation below;
Rate = k[aldehyde][NaBH4]
The Rate of the reaction is directly proportional to NaBH4 concentration.
Therefore since they are directly proportional, when the amount of NaBH4 is increased, we will also have the overall reaction rate increase.
When we measure the heat of combustion of glucose, C6H12O6, in a bomb calorimeter, what products are formed in the reaction
Answer:
H for the combustion reaction:
C6H12O6(s) + 6O2(g) => 6CO2(g) +6H2O(g)
The answer is -2.81 x 103kJ
Explanation:
The equation for the combustion of glucose is[tex]C_6H_1_2 O_6 + 6 O_2 ----- > 6 CO_2 + 6 H_2 O[/tex]
The products formed in this reaction are Carbon dioxide and Water.
What is Combustion?Combustion is a type of chemical reaction that takes place between substances that involves oxygen and produces heat and light in the form of a flame at which the rate of reactant combination is very high as the chemical reaction is in nature due to which more energy is released as a result of which the temperature of the reactant increases and accelerates the reaction even more.
It is a type of exothermic redox chemical reaction occur between a fuel that is a reductant and an oxidant. Burning is an another word for combustion.
Examples of combustion include a burning matchstick – when the matchstick is struck against a matchbox, the friction heats the head of the matchbox to a temperature at which the chemical reacts and produces more heat, which then goes out into the air and gets burnt in the flame.
For above statement, The products formed in heat of combustion of glucose are Carbon dioxide and Water
Thus, the equation for the combustion of glucose is[tex]C_6H_1_2 O_6 + 6 O_2 ----- > 6 CO_2 + 6 H_2 O[/tex]
The products formed in this reaction are Carbon dioxide and Water.
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guys please help me with this periodic table homework is really IMPORTANT FOR ME
Answer:
A, Chlorine, Cl
Explanation:
A magnet can be used to.
Bubble A. attract metal objects
Bubble B. measure the length of an object
Bubble C. measure the temperature of an object
Bubble D. measure the mass of an object
Answer:
D.measure the mass of an object
Answer: a attract metal objects
Explanation:
are you slow this is the easiest thing ever
When temperature drops, the number of collisions between particles increases
True?
False?
When fertilizers enter surface water, they cause problems in the watershed by -
A. clogging narrow streams and preventing water from flowing properly.
B. increasing the amount of nutrients available to fish in lakes and streams.
C. causing rapid algal growth that decrease oxygen levels and choke aquatic life.
D. raising the water level in nearby rivers to levels leading to flooding.
C: Causing rapid algal growth that decreases oxygen levels and chokes aquatic life.
If this is incorrect, please, don't refrain to tell me. Thank you.
When fertilizers enter the water surface they cause brisk algal growth, which reduces the levels of oxygen and choke aquatic life.
What is eutrophication?It is the phenomenon by which the entire water body, or some part of it becomes enriched with nutrients and minerals, mainly the phosphorus and nitrogen. This generally takes place when the fertilizers used in fields get washed in the water body.
A common effect of eutrophication is algal blooms. The emergence of algal blooms results in the depletion of oxygen of the water body resulting in the choking of aquatic life.
Thus, the correct answer is option C.
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determine the empriical fornula of warfarin, a rodenticide which consists of 74.01% C, 5.23% H, and 20.76% o by mass
Answer:
Explanation:
C = 74.01 %
H= 5.23 %
O=20.76 %
Ratio of moles of C , H , O
= 74.01 / 12 : 5.23 / 1 : 20.76 / 16
= 6.1675 ;5.23 : 1.2975
= 4.75 : 4.03 : 1
= 4.75 / .25 : 4.03 / .25 : 1/.25
= 19 : 16 : 4
Empirical formula
= C₁₉ H₁₆O₄ .
Rank the SN1 reaction rates for the following compounds: (A) chloromethane, (B) 3-chloro-3-methylpentane, (C) 1-chloro-3-methylpentane, (D) 2-chloro-3-methylpentane
Answer:
3-chloro-3-methylpentane,>2-chloro-3-methylpentane> 1-chloro-3-methylpentane, > chloromethane
Explanation:
The rate of SN1 reactions decreases in the order, tertiary > secondary > primary > methyl.
This implies that, a tertiary alkyl halide is better able to undergo nucleophilic substitution by SN1 mechanism compared to a secondary, primary or methyl.
This is because, the transition state leading to the formation of an SN1 product involves a carbocation. The order of stability of carbocations is; tertiary > secondary > primary > methyl.
Hence a tertiary alkyl halide such as 3-chloro-3-methylpentane leads to a more stable transition state and undergoes SN1 reaction at a faster rate.
hen aqueous solutions of calcium bromide and sodium carbonate are combined, solid calcium carbonate and a solution of sodium bromide are formed. The net ionic equation for this reaction is:
Answer:
[tex]Ca^{2+}(aq)+CO_3^{2-}(aq)\rightarrow CaCO_3 (s)[/tex]
Explanation:
Hello.
In this case, we can first write the complete molecular equation as shown below:
[tex]CaBr_2(aq)+Na_2CO_3\rightarrow CaCO_3 (s) +2NaBr(aq)[/tex]
In such a way, since all the species but calcium carbonate remain in aqueous solution, they are successfully dissociated whereas the solid product remain undissociated:
[tex]Ca^{2+}(aq)+2Br^-(aq)+2Na^+(aq)+CO_3^{2-}(aq)\rightarrow CaCO_3 (s) +2Na^+(aq)+2Br^-(aq)[/tex]
Thus, we can cancel out bromide and sodium ions as spectator ions, in order to obtain the required net ionic equation:
[tex]Ca^{2+}(aq)+CO_3^{2-}(aq)\rightarrow CaCO_3 (s)[/tex]
Best regards!
Ne belongs to what group. a. noble gases, b.alkali metals, c. halogens, d. alkaline earth metals
You are given 10.00 mL of a solution of an unknown acid. The pH of this solution is exactly 4.08. You determine that the concentration of the unknown acid was 0.3250 M. You also determined that the acid was monoprotic (HA). What is the pKa of your unknown acid
Answer:
Explanation:
pH = 4.08
[ H⁺ ] = 10⁻⁴°⁰⁸
= 8.3 x 10⁻⁵
concentration of acid = .3250 M
HA ⇆ H⁺ + A⁻
.325 8.3 x 10⁻⁵ 8.3 x 10⁻⁵
Ka = (8.3 x 10⁻⁵ )² / .325
= 68.9 x 10⁻¹⁰ / .325
= 212 x 10⁻¹⁰ M .
pKa = - log ( 212 x 10⁻¹⁰ )
= 10 - log 212
= 10 - 2.32
= 7.68 .
Insulin is a protein that is used by the body to regulate both carbohydrate and fat metabolism. A bottle contains 125 mL of insulin at a concentration of 50.0 mg/mL . What is the total mass of insulin in the bottle?
Answer:
the total mass of insulin in the bottle would be 3.75 g
hope this helps :)
Explanation:
c= 50 mg/mL
m = ?
v = 125 mL
c=m/v
[tex]\frac{50mg}{mL}[/tex]=[tex]\frac{m}{125mL}[/tex]
m=30×125
m=3750 mg or 3.75 g
Insulin has been the peptide hormone that is produced by the pancreatic cell of the body. The insulin solution of a concentration of 50 mg/ml has a mass of 6.25 grams.
What is insulin?Insulin has been the protein that is crucial for cell activity and function. It is a hormone that regulates the blood glucose level in a diabetic patient. The beta cell of the islets of the Langerhans of the pancreas makes insulin.
The glucose formed from the breaking of carbohydrates is controlled in the blood by insulin production so that the metabolic process can take place in an orderly manner.
Given,
Concentration of insulin hormone = 50 mg/mL
The volume of insulin in bottle = 125 mL
The mass of insulin can be calculated from the molar concentration and volume as:
Concentration = mass ÷ volume
Substituting the values above as:
50 mg/mL = mass ÷ 125 mL
Mass = 50 mg /mL × 125 mL
Mass = 6250 mg
The unit of mass is converted from milligram into gram as:
1 gm = 1000 mg
x gm = 6250 mg
x = 6.250 gm
Therefore, 50 gm/mL of concentration has 6.25 gm of insulin in it.
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what is unusual about the rotation of Venus
Answer:
Other planets rotate counterclockwise, but Venus rotates clockwise. Scientists believe this is due to an impact with a celestial body that occurred billions of years ago.
Explanation:
The rotation of Venus is unusual in a few ways like retrograde rotation,slow rotation.
1. Retrograde Rotation: Venus rotates in the opposite direction compared to most other planets in our solar system. While Earth and other planets rotate counterclockwise when viewed from the North Pole, Venus rotates clockwise. This retrograde rotation makes Venus unique among the planets in our solar system.
2. Slow Rotation: Venus rotates very slowly, taking around 243 Earth days to complete one rotation on its axis. This is longer than the time it takes for Venus to complete one orbit around the Sun, which is about 225 Earth days. As a result, a day on Venus (one complete rotation) is longer than its year (one orbit around the Sun).
Thus,these unique characteristics of Venus' rotation contribute to its distinct atmospheric conditions and extreme temperature variations between the day and night sides of the planet.
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Alkali metals tend to be more reactive than alkaline earth metals because ________. Alkali metals tend to be more reactive than alkaline earth metals because ________. alkali metals have lower melting points alkali metals have lower densities alkali metals have greater electron affinities alkali metals have lower ionization energies Alkali metals are not more reactive than alkaline earth metals.
Answer:alkali metals have lower ionization energies
Explanation:
----Alkali metals tend to be more reactive than alkaline earth metals because alkali metals have lower ionization energies
Alkali metals are metals found in group 1 and examples are Lithium, Sodium and potassium having 1 electron in their outermost shell, Alkali earth metals on the other hand are found in group 2 of the periodic table and examp-les of which are Beryllium, magnesium, Calcium having 2 electrons in their outermost shells
Alkali metals are more reactive than the alkali earth metal due to the former having a lower ionization energy as we know , Ionization energy is the lowest energy it takes to remove a mole of electron from a mole of atom in gaseous sate, We can now see that it will take a very small amount to remove 1 valence electron than two valence electrons and the ability to easily loose electron makes an element more reactive.
Answer:
Alkali metals tend to be more reactive than alkaline earth metals because-
Explanation:
The more easily an electron is lost, the more reactive it is. Alkalines have 2 valence electron (electrons on the outer shell) whereas, Alkalis have 1 valence electron. So Alkaline's bond is stronger. An increase in density also increases the attraction force between nucleus and electron. Therefore Alkali are more reactive.
What volume in mL of 0.300 M NaF would be required to make a 0.0715 M solution of NaF when diluted to 250.0 mL with water
Answer: The volume of 0.300 M NaF required is 59.6 ml
Explanation:
According to the dilution law,
[tex]C_1V_1=C_2V_2[/tex]
where,
[tex]C_1[/tex] = concentration of concentrated NaF solution = 0.300 M
[tex]V_1[/tex] = volume of pure concentrated Na F solution = ?
[tex]C_2[/tex] = concentration of diluted NaF solution= 0.0715 M
[tex]V_2[/tex] = volume of diluted NaF solution= 250.0 ml
[tex]0.300\times x=0.0715\times 250.0[/tex]
[tex]x=59.6ml[/tex]
Thus the volume of 0.300 M NaF required is 59.6 ml
When 1.34 g Zn(s) reacts with 60.0 mL of 0.750 M HCl(aq), 3.14 kJ of heat are produced. Determine the enthalpy change per mole of zinc reacting for the reaction:
Answer:
Explanation:
Zn + 2HCl = ZnCl₂ + H₂
1 mole 2 mole
1.34 g = 1.34 / 65. = .0206 mole
60 mL of .75 M HCl = .045 mole of HCl
so full .0206 mole of Zn will react with .0412 mole of HCl
.0206 mole of Zn gives out 3.14 kJ of heat
1 mole of Zn will react to give 152.43 kJ of heat
enthalpy change of heat per mole of Zn
= 152.43 kJ .
For the reaction, Ni (s) and HCl (aq), write the molecular, complete ionic and net ionic equations. Note: most likely charge on the nickel cation is +2.
Answer:
Explanation:
Balanced Molecular reaction
[tex]Ni(s) + 2HCl(aq)[/tex] →[tex]NiCl2(aq) +H2(g)[/tex]
Complete ionic reaction
[tex]2 H^+ (aq) + 2 Cl^- (aq) + Ni (s)[/tex]→[tex]Ni^2+ (aq) + 2 Cl^- (aq) + H2 (g)[/tex]
Net ionic reaction
[tex]Ni(s)+ 2H^+(aq)[/tex]→[tex]Ni^2+(aq) + H2(g)[/tex]
what is a way that scientists communicate their
results to others?
HELP PLS!
Answer:
The main ways that scientists communicate research results is by publishing the results in journals. ... Some journals are peer-reviewed, meaning they only publish articles that pass a certain standard of quality -- peer-reviewed journals are usually for a specific audience, such as other scientists.
Explanation:
Calculate the pH of a 0.20 M NH3/0.20 M NH4Cl buffer after the addition of 15.0 mL of 0.10 M HCl to 65.0 mL of the buffer.
Which element is oxidized in the following reaction? Fe(s) + 2HCL(aq) -FeCL2(aq) + H2(g)
What influences electrical conductivity?
Answer:Electrical conductivity of earth materials is influenced by the metal content (sulfides) in the rock, porosity, clay content, permeability, and degree of pore saturation. hope this helps
Explanation:
What atom has an atomic radius larger than iron? Cl Ca Se C
Answer:
Ca
Explanation:
Atomic radii vary in a predictable way across the periodic table. As can be seen in the figures below, the atomic radius increases from top to bottom in a group, and decreases from left to right across a period. Thus, helium is the smallest element, and francium is the largest.
Which is the attractive force of an ionic bond?
A. a charged atom to a similarly charged atom
B. a positively charged ion to an oppositely charged ion
C. one or more electrons to one or more protons
D. a charged atom to a neutral atom
The pH of a solution after a base and an acid have neutralized each other is ___.
Group of answer choices
A) 6
B) 8
C) 7
D) 0
Answer: B
Explanation:
Which of the following metals will not react with sulfuric acid (H2SO4(aq)) by single displacement reaction?
Zinc, magnesium, iron, silver
Answer:
Silver
Explanation:
Silver (Ag) will not react with sulfuric acid (H2SO4(aq)) by single displacement reaction. This is because in the electrochemical series (activity series), silver is below hydrogen and it's less reactive.
The other elements stated (Zinc, Magnesium, Iron) are higher than hydrogen in the activity series and will definitely displace hydrogen in single displacement reaction.
A single-displacement reaction is known as a chemical reaction which occurs which one element is actually replaced or displaced by another in a compound. We represent it as:
B + D-C ➡️ B-C + D
This will readily take place if B is more reactive than D, and it will finally give a more stable product.
(1.6): What volume of oxygen, at 18°C and 750 torr, can be
obtained from heating 100gm of potassium chlorate, KCIO,?
Answer:
Volume of oxygen obtained = 30 L
Explanation:
Given data:
Mass of KClO₃ = 100 g
Pressure = 750 torr = 750/760 = 0.98 atm
Temperature = 18°C = 18+273 = 291 K
Volume of oxygen obtained = ?
Solution:
Chemical equation:
2KClO₃ → 3O₂ + 2KCl
Number of moles of KClO₃:
Number of moles = mass/molar mass
Number of moles = 100 g/ 122.55 g/mol
Number of moles = 0.82 mol
Now we will compare the moles of KClO₃ with oxygen.
KClO₃ : O₂
2 : 3
0.82 : 3/2×0.82 = 1.23 mol
Volume of oxygen:
PV = nRT
0.98 atm × V = 1.23 mol ×0.0821 atm.L/mol.K × 291 K
0.98 atm × V = 29.4 atm.L
V = 29.4 atm.L /0.98 atm
V = 30 L
A sample of hydrogen sulfide has a mass of 73.00 g. Calculate the number of hydrogen sulfide molecules in the sample.
Answer:
1.29×10²⁴ molecules.
Explanation:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ molecules. Thus, 1 mole of Hydrogen sulfide (H2S) contains 6.02×10²³ molecules.
Next, we shall determine the mass of 1 mole of H2S. This is illustrated below:
1 mole of H2S = (2×1) + 32 = 34 g
Finally, we shall determine the number of molecules in 73 g of H2S as follow:
34 g of H2S contains 6.02×10²³ molecules.
Therefore, 73 g of H2S will contain =
(73 × 6.02×10²³) /34 = 1.29×10²⁴ molecules.
Thus, 73 g of H2S will contain 1.29×10²⁴ molecules.
