Was the periodic table of elements created at once by one scientist yes or no
Answer:
Yes
Explanation:
It was Dmitri Mendeleev, a Russian chemist and teacher.
Answer:
No, it wasn't. On Feb.17 in 1869, a very intelligent Russian professor of chemistry, Dimitri Ivanovich Mendeleev created his first part of the periodic table. I hope that helps you.
Explanation:
12. What is the frequency of a photon with an energy of 3.03 x 10-19 J?
(Planck's constant: h=6.63x 10-34 J·s) (E =hu)
a. 1.98x10^-18 Hz
b. 4.58x10^14 Hz
c. 2.16x10^14 Hz
d. 4.39x10^-19 Hz
Answer:
[tex]u=4.57x10^5GHz[/tex]
Explanation:
Hello.
In this case, given the formula:
[tex]E=h*u[/tex]
Whereas E is the energy, h the Planck's constant and u the frequency of the photon. Thus, solving for it, we obtain:
[tex]u=\frac{E}{h}=\frac{3.03x10^{-19}J}{6.63x10^{-34}J*s}\\ \\u=4.57x10^{14}s^{-1}[/tex]
Or also:
[tex]u=4.57x10^{14}Hz*\frac{1GHz}{1x10^9Hz}\\ \\u=4.57x10^5GHz[/tex]
Best regards.
Classify the sugars as either aldoses or ketoses. A Fischer projection with a six carbon backbone. Carbon one is an aldehyde and carbon six is part of the group C H 2 O H. Carbons two and three have an hydroxide group on the left, and carbons four and five have an hydroxide group on the right. A Fischer projection of a six carbon backbone. Carbons one and six are part of a C H 2 O H group. Carbon two is attached to a ketone, carbons three and four have a hydroxide group on the left, and carbon five has a hydroxide group on the right. A Fischer projection with a five carbon backbone. Carbon one is an aldehyde, carbon five is part of the group C H 2 O H, and carbons two through four have an hydroxide group on the right. A Fischer projection with a three carbon backbone. Carbon one is an aldehyde, carbon three contains the group C H 2 O H, and carbon two has a hydroxide group on the right. A Fischer projection with a five carbon backbone. Carbons one and five are part of a C H 2 O H group. Carbon two is attached to a ketone and carbons three and four have a hydroxide group on the right. A Fischer projection of a four carbon backbone. Carbons one and four are part of a C H 2 O H group. Carbon two is attached to a ketone and carbon three has a hydroxide group on the right. Answer Bank
Answer AND Explanation: Carbohydrates or sugars have three classes:
Monossaccharides: made from a single polyhydroxy aldehyde or ketone unit;Oligosaccharides: formed by short chains of monossacharides united by glycosidic linkage;Polysaccharides: consist of a long chain of monossaccharides;Monossaccharides are formed by a chain of unbranched carbon, all bonded by single bonds, except for a carbon that is double-bonded by an oxygen. This bond form a carbonyl group.
If the carbonyl is at an end of the chain, the carbon is aldehyde and the molecule is called aldose. If the group is in any other position, it is a ketone and is called ketose
So analysing each projection:
1) Carbon one is a aldehyde, which means is a carbonyl and there are no other carbons forming that bond, so it's a ALDOSE
2) Carbon two is attached to a ketone and other carbons aren't, so it's a KETOSE.
3) Carbon one is aldehyde, so it's ALDOSE
4) Carbon one is aldehyde, so ALDOSE
5) Carbon two is attached to ketone, so KETOSE
6) Carbon two attached to a ketone, so KETOSE
1. 500 grams of sugar occupies a volume of 315 ml. What is the density of the sugar in g/mL? Show
your work.
Answer:
The answer is 1.59 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\[/tex]
From the question
mass = 500 g
volume = 315 mL
We have
[tex]density = \frac{500}{315} = \frac{100}{63} \\ = 1.587301...[/tex]
We have the final answer as
1.59 g/mLHope this helps you
Whose measurements are more precise?20.3 cm and 21.0cm
Answer:
will i think the 21.0cm
3. Describe the trends in atomic size, ionization energy, and electronegativity from left to right across a period in
the periodic table.
Answer:
Atomic size increase with increasing atomic number within a group.
Atomic size decrease with increasing atomic number across a period.
The statement, that describe the trends in atomic size, ionization energy, and electronegativity is "that atomic size decreases, ionization energy and electronegativity increases."
What is atomic size?Atomic size seems to be the space between an atom's nucleus and its outermost shell.
What is ionization energy?The energy necessary to remove the highest-energy electron from a neutral atom is known as ionization energy (IE).
What is electronegativity?Electronegativity is a chemical property that describes an atom's or functional group's inclination to draw electrons toward itself. Across a period of elements, atomic size falls steadily from left to right. This is because all electrons within a period or family of elements are added to the same shell. Ionization energy generally increases across a period and declines down a group.
Electronegativity normally increases as you move from left to right across a period and decreases as you move down a group on the periodic table.
Hence the correct answer is atomic size decreases, ionization energy and electronegativity increases.
Learn more about atomic size , ionization energy and electronegativity
https://brainly.com/question/16243729
#SPJ2
Do you agree in the Big Bang theory? Reasoning
Determine the milliliters of paint in a 5.0 gallon bucket
Ans: 18950 ML
Answer:
the answer is 18,927,06.
Explanation:
I just took the test ; )
A 4.534 g sample of a solid mixture was analyzed for barium ion. First the rock was crushed in a mortar and pestle. 100% of the sample was transferred to a beaker, where it was dissolved in 150.0 mL of d.i. water. to give 152 mL of solution. The aqueous sample was then analyzed by adding a small excess of sulfuric acid. The resultant reaction produced a precipitate of barium sulfate, which was collected by filtration, rinsed, dried and weighed. If 0.5376 g of barium sulfate was obtained, what was the mass percent of barium in the original sample? What was the molar concentration barium in the 152 mL of solution prior to adding sulfuric acid? Show work clearly; include a balanced net ionic chemical equation, units and sig. figs.
Answer:
6.976%
0.0152 M
Explanation:
Step 1: Write the balanced chemical equation
Ba²⁺(aq) + H₂SO₄(aq) ⇒ BaSO₄(s) + 2 H⁺(aq)
The balanced net ionic chemical equation is:
Ba²⁺(aq) + SO₄²⁻(aq) ⇒ BaSO₄(s)
Step 2: Calculate the moles corresponding to 0.5376 g of BaSO₄
The molar mass of BaSO₄ is 233.39 g/mol.
0.5376 g × (1 mol/233.39 g) = 2.303 × 10⁻³ mol
Step 3: Calculate the moles of Ba²⁺ that produced 2.303 × 10⁻³ moles of BaSO₄
The molar ratio of Ba²⁺ to BaSO₄ is 1:1. The moles of Ba²⁺ are 1/1 × 2.303 × 10⁻³ mol = 2.303 × 10⁻³ mol.
Step 4: Calculate the mass corresponding to 2.303 × 10⁻³ moles of Ba²⁺
The molar mass of Ba²⁺ is 137.33 g/mol.
2.303 × 10⁻³ mol × 137.33 g/mol = 0.3163 g
Step 5: Calculate the mass percent of barium in the original sample
0.3163 g of barium ion were in a 4.534 g-sample. The mass percent of barium ion is:
0.3163 g/4.534 g × 100% = 6.976%
Step 6: Calculate the molar concentration barium in the 152 mL of solution
2.303 × 10⁻³ moles of barium ion were in 152 mL (0.152 L) of solution. The molarity of barium ion is:
M = 2.303 × 10⁻³ mol/0.152 L = 0.0152 M
How many total atoms are in one molecule of maltose?
Answer:
The total number of atoms is 12 + 22 + 11 = 45, so carbon atoms are 12/45 of the total.
Explanation:
Calculate the density of the following material: 500 kg gold with a volume of 0.026 m³.
Answer:
The answer is 19230.8 kg/m³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\[/tex]
From the question
mass = 500 kg
volume = 0.026 m³
We have
[tex]density = \frac{500}{0.026} \\ = 19230.769230...[/tex]
We have the final answer as
19230.8 kg/m³Hope this helps you
The salt copper(II) sulfate dissolves in water according to the reaction: CuSO4(s) Cu2+(aq) + SO42-(aq) (a) Calculate the standard enthalpy change ΔH° for this reaction, using the following data: CuSO4(s) = -771.4 kJ mol-1 Cu2+(aq) = 64.8 kJ mol-1 SO42-(aq) = -909.3 kJ mol-1 kJ (b) Calculate the temperature reached by the solution formed when 13.0 g of CuSO4 is dissolved in 0.109 L of water at 25.0 °C. Approximate the heat capacity of the solution by the heat capacity of 109 g of pure water (specific heat capacity = 4.18 J g-1 °C-1), ignoring the mass of the salt. °C (c) Heats of reaction find practical application in hot packs or cold packs. Would this dissolution reaction be appropriate for the preparation of a hot pack or a cold pack?
Answer:
(a) [tex]\Delta H=-73.1\frac{kJ}{mol}[/tex]
(b) [tex]T_2=38.1\°C[/tex]
(c) Yes, it is appropriated.
Explanation:
Hello.
(a) In this case, given the formation enthalpies for copper (II) sulfate, copper (II) ion and sulfate ion, we can compute the enthalpy change for such process as follows:
[tex]\Delta H=\Delta H_{Cu^{2+}}+\Delta H_{SO_4^{-2}}-\Delta H_{CuSO_4}\\\\\Delta H=64.8-909.3-(-771.4)\\\\\Delta H=-73.1\frac{kJ}{mol}[/tex]
(b) In this case, since 13.0 g of copper (II) sulfate (molar mass: 159.55 g/mol) we can compute the gained heat by water via:
[tex]Q_{water}=-n_{CuSO_4}\Delta H=-13.0g*\frac{1mol}{159.55g}* -73.1\frac{kJ}{mol}\\ \\Q_{water}=5.96kJ=5960J[/tex]
As the heat lost by the reaction is gained by the water, therefore, the final temperature is:
[tex]Q_{water}=m_{water}Cp_{water}(T_2-T_1)\\\\T_2=T_1+\frac{Q_{water}}{m_{water}Cp_{water}}\\ \\T_2=25.0\°C+\frac{5960J}{0.109L*\frac{1000g}{1L}*4.18\frac{J}{g\°C} } \\\\T_2=38.1\°C[/tex]
(c) In this case, since this dissolution reaction is exothermic as it increases the temperature when undergone, we can infer that yes, this dissolution would be appropriate for the preparation of a hot pack, because a cold pack would be with an endothermic dissolution reaction.
Best regards.
3. Where are gastropods found? Choose all the correct answers.
A) on land
OB) in salt water
OC) in fresh water
OD) all of the above
O E Maastropods are extinct
Save
Answer:
OD
Explanation:
they live in every habitat on Earth. Marine habitats, ocean basins, freshwater habitats, and inland equatic habitats including salt lakes.
What would be the formal charge of N in NO2?
Answer:
What would be the formal charge of N in NO2?
Explanation:
The nitrogen gets two electrons for the double bond, one from the single bond and one from the half-filled orbital associated with it. That's a total of 4 and gives N a +1 formal charge since itneeds 5 to be neutral. The Rules for Writing Lewis Structures has some discussion of formal charge in it.
do people cause melting glaciers
Answer:
Human activities are at the root of this phenomenon.
Explanation:
do it if u trust urself
Which statement provides the complete explanation of how renewable and nonrenewable resources differ?
They differ in the amount they are found in nature.
They differ in the rate they are replaced.
They differ in the available amount and rate they are used and replaced.
They differ in the rate they are used.
Answer:
They differ in the available amount and rate they are used and replaced.
Explanation:
If one material is replaceable, then it's renewable. If it's not replaceable, then it's non-renewable.
The statement 'they differ in the available amount and rate they are used/replaced' provides an explanation of how renewable and nonrenewable resources differ.
What are renewable resources?Renewable resources can be defined can natural resources that can be renowned in nature in a given period of time.
These renewable resources include biomass and different types of energies (geothermal, wind, solar, etc). Conversely, non-renewable resources are specific resources from nature that cannot be replaced (e.g., coal).In conclusion, the statement 'they differ in the available amount and rate they are used/replaced' provides an explanation of how renewable and nonrenewable resources differ.
Learn more about renewable resources here:
https://brainly.com/question/79953
#SPJ2
what is the formula for sodium hydrogen phosphate
Answer: Na2HPO4
Explanation: this is the formula
Answer:
Na3PO4
Explanation:.
What are two ways nitrogen fixation occurs
Explanation:
natural process
biological fixation
Calculate the energy of a wave given a frequency of
9.43 x 1011 Hz.
Answer:
The answer is
[tex]4.92 \times {10}^{ - 22} \: J[/tex]
Explanation:
In order to find the energy of the wave we use the formula
e = hfwhere
e is the energy
f is the frequency
h is the Planck's constant which is
6.626 × 10-³⁴ Js
From the question
f = 9.43 × 10¹¹ Hz
We have
[tex]e = 9.43 \times {10}^{11} \times 6.626 \times {10}^{ - 34} \\ [/tex]
We have the final answer as
[tex]4.92 \times {10}^{ - 22} \:J[/tex]
Hope this helps you
Which of the following describes a chemical change?
A. a suspension of corn starch and water
B. formation of a precipitate
C. formation of a solution
D. filtration of a solid from a liquid
Answer:
C
Explanation:
Have a nice day
What is cheese made of is it like a piece of moon ?!
Answer:
It's made from dairy.
Explanation:
The closeness of particles of gas and their low speeds allow intermolecular forces to become important at certain
pressures and temperatures. Which best describes this statement?
Answer:
This is a limitation of the kinetic-molecular theory.
Explanation:
What makes metals, in particular, good conductors of electricity?
A.
the ability of electrons to flow throughout the metal
OB.
the absence of charged particles
O c.
the high temperatures required to break metallic bonds
D.
the presence of positive and negative ions
Answer: I believe the answer is A
Here is a more complex redox reaction involving the permanganate ion in acidic solution
In the redox reaction involving the permanganate ion in acidic solution, permanganate ion is reduced to manganese (ii) ion while iron (ii) ion is oxidized to iron(iii) ion.
What is a redox reaction?A redox reaction is a reaction in which reduction and oxidation occurs at the same time and to the same extent.
An example of a redox reaction is the reaction involving the permanganate ion and tetraoxosulphate (vi) ion in acidic solution.
The equation of the reaction is given below:
[tex]MnO_{4}^{ - } (aq) + 5Fe^{2+}(aq) + 8H^{+} \rightarrow Mn^{2+}(aq)+ 5Fe^{3+}(aq) +4H_{2}O(l) \\ [/tex]
Therefore, in the redox reaction involving the permanganate ion in acidic solution, permanganate ion is reduced to manganese (ii) ion while iron (ii) ion is oxidized to iron(iii) ion.
Learn more about redox reaction at: https://brainly.com/question/26750732
#SPJ1
which surface events are examples of weathering
Answer:Weathering Erosion & Deposition
Changes in shape, size, and texture of land-forms (i.e. mountains, riverbeds, and beaches)
Landslides.
Buildings, statues, and roads wearing away.
Soil formation.
Washes soil, pollutants, harmful sediments into waterways.
Causes metals to rust.
Reduces beaches, shorelines.
Delta formation.
Explanation:
Which properties makes a metal a good material to use for electrical wires?
A. Malleability and reactivity
B. Conductivity and ductility
C. Ductility and malleability
D. Reactivity and conductivity
Answer:
D
Explanation:
Because a metal must reactive and able to conduct
Answer:
B.Conductivity and ductility
Explanation.
Some metals are conductive and are ductile
Conductivity is the ability to have an electric flow
Ductility is the ability to bend
Which of the following items would improve the experiment? Add more types of plants Test one plant with no fertilizer Use different soils for each plant Expose all six plants to green light
Answer:
Um, I'd say add more types of plants cause different plants react differently to things, I guess?
the valency of nitrogen is 3 why
Answer:
The nitrogen atom has 5 electrons in the outermost shell, so it can accept 3 electrons to fulfil the octet structure. Therefore the valency of nitrogen is 3.
Determine the number of liters in a 355 milliliter can of soda.
Ans: 0.355 L
Which statement best explains why gases are poor conductors of thermal energy?
Answer:
Thermal Insulators
That's because air, like other gases, is a poor conductor of thermal energy. The particles of gases are relatively far apart, so they don't bump into each other or into other things as often as the more closely spaced particles of liquids or solids
Explanation:
