Answers
Answer:
Leeunwenhoek
Explanation:
Anton Von Leeunwenhoek was the first scientist to observe live cells and in greater details. He described spirogyra in the mid 15th century.
His contribution to the scientist community opened up the world of micro-organisms. He produced several microscopes to observed the world of micro-organisms that we cannot see with our naked eyes. He also studied plants extensively.Related Questions
Which group of organisms is an example of a population?
Answers
Answer:Leopard Frogs all together in a stream
Explanation:
Consider these two cases.
Case 1: An electron jumps from energy level 3 to energy level 7 in an atom.
Case 2: An electron jumps from energy level 3 to energy level 9 in an atom.
For case 1, what happens when an electron jumps from energy level 3 to energy level 7 in an atom?
A neutron is absorbed by the atom.
A photon is emitted by the atom.
A photon is absorbed by the atom.
A neutron is emitted by the atom.
Assuming that both cases describe Hydrogen‑like atoms with one electron, for which case is more energy emitted or absorbed?
More energy is emitted or absorbed for case 1.
The energy is the same for both cases.
More energy is emitted or absorbed for case 2.
It is impossible to tell.
Answers
Answer:
A photon is absorbed by the atom.
Explanation:
In case 2 where an electron jumps from energy level 3 to energy level 9, a photon is absorbed by the atom.
Photon is the basic unit of energy used to describe electromagnetic radiation.
When an electron moves from a lower energy level to a higher one, it absorbs energy. This energy is in form of photon. Level is a lower energy level compared to 9.II. A photon is absorbed by the atom.
It is the same scenario as case 2
III. More energy is emitted or absorbed for case 2.
More energy is emitted or absorbed for case 2 because the transition involves movement from a level to a greater level than that of case 1.
47. A substance has a half life of 3min. After 5 min, the
count rate was observed to be 400 what was its
count rate at rate at zero time?
2
Answers
Answer:
1000
Explanation:
PLS GIVE BRAINLIEST
Based on your observations how are the top left and bottom left numbers of an atom symbol different?Explain
Answer as fast as you can I need it right now please
Answers
Answer:
The top left number of the symbol of an atom is the sum of the protons and neutrons in the atom known as atomic mass number, while the bottom left number of the symbol of an atom is the number of protons in the atom known as atomic number.
Explanation:
An atom of an element is composed of other subatomic particles; the electron, proton and neutron. The number of protons present in an atom of an element is equal to the number of electrons present in the atom of that element and is known as the atomic number of the element. The number of neutrons present in the atom summed together with the proton number gives the atomic mass number of an atom of the element.
Elements are represented with symbols. In writing the symbols of elements, the atomic number and the atomic mass of an atom of the element is usually written along with the symbol. The top left number of the symbol of an atom is the sum of the protons and neutrons in the atom, while the bottom left number of the symbol of an atom is the number of protons in the atom.
For example, the element sodium has an atomic number of 11 and a mass number of 23. In symbols, it is written as follows: ²³₁₁Na
Convert the speed of light, 3.0 x 10^8 m/s, into mi/hr. (1610 m = 1 mi). Could you please explain step by step thank you!
Answers
Answer:
[tex]v=6.7\times 10^9\ mi/hr[/tex]
Explanation:
Given that,
The speed of light is 3×10⁸ m/s
We need to convert it into mi/hr.
Since, 1 mile = 1610 m
1 hour = 3600 s
So,
[tex]v=3\times 10^8\ \dfrac{m}{s}\\\\=3\times 10^8\ \dfrac{\dfrac{1}{1610}\ \text{miles}}{\dfrac{1}{3600}\ s}\\\\=6.7\times 10^9\ mi/hr[/tex]
So, the required speed of light is [tex]6.7\times 10^9\ mi/hr[/tex].
A solution is made by adding 5.01 g of iron sulfate to 75.3 g of water. What is the mass percentage of iron sulfate in this solution?
Answers
Answer:
6.24 % of FeSO₄
Explanation:
Solute mass: 5.01 g of FeSO₄
Solvent mass: 75.3 g of water
Solution mass = solute mass + solvent mass
5.01 g + 75.3 g = 80.31 g
We can apply a rule of three. Mass percentage means the mass of solute which is contained in 100 g of solution. Then,
In 80.31 g of solution we have 5.01 g of solute
In 100 g solution, we may have (5.01 . 100)/ 80.31 = 6.24 g of solute.
This is the mass percentage: 6.24%
what are atoms made up of
Answers
Answer:
They are made up of electrons, neutrons and protons
Explanation:
Suppose you are titrating vinegar, which is an acetic acid solution, of unknown strength with sodium hydroxide according to the equation HC2H3O2 + NaOH → H2O + NaC2H3O2 If you require 32.17 mL of 0.116 M NaOH solution to titrate 10.0 mL of HC2H3O2 solution, what is the concentration of acetic acid in the vinegar? (M)
Answers
Answer:
0.373 M
Explanation:
The reaction is
HC₂H₃O₂ + NaOH → H₂O + NaC₂H₃O₂So 1 mol of acetic acid reacts with 1 mol of sodium hydroxide.
First we calculate the moles of NaOH:
0.116 M * 32.17 mL = 3.732 mmol NaOHBecause the stoichiometric ratio is 1:1 :
3.732 mmol NaOH = 3.732 mmol Acetic AcidNow we calculate the concentration of acetic acid, dividing the moles by the volume:
3.732 mmol Acetic Acid / 10.0 mL = 0.373 M32.17 mL of 0.116 M NaOH are required to titrate 10.0 mL of 0.373 M acetic acid.
What is titration?Titration is a common laboratory method of quantitative chemical analysis to determine the concentration of an identified analyte.
Let's consider the neutralization reaction between acetic acid and sodium hydroxide.
HC₂H₃O₂ + NaOH → H₂O + NaC₂H₃O₂
We can calculate the concentration of acetic acid in vinegar using the following expression.
Ca × Va = Cb × Vb
Ca = Cb × Vb / Va
Ca = 0.116 M × 32.17 mL / 10.0 mL = 0.373 M
where,
Ca is the concentration of the acid.Va is the volume of the acid.Cb is the concentration of the base.Vb is the volume of the base.32.17 mL of 0.116 M NaOH are required to titrate 10.0 mL of 0.373 M acetic acid.
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Solve a + b + c, when a =25.164, b =74.1
Answers
Here we go the answer is in photo form please!!!
Which statement is true of an endothermic reaction? a) Weak bonds break and strong bonds form. b) Strong bonds break and weak bonds form. c) The bonds that break and those that form are of approximately the same strength.
Answers
Answer:
B
Explanation:
In an endothermic reaction, strong bonds break and weak bonds form.
Which of these elements can form a double bond in a molecule?
A. oxygen (0)
B. chlorine (CI)
C. hydrogen (H)
D. neon (Ne)
Answers
Answer:
?
Explanation:
Answer:
your answer is A
Consider two gaseous systems: one for which the Vrms of the particles is low and another for
which the Vrms of the particles is high. What can you say about the relative temperatures of
each system?
Answers
Answer:
See explanation
Explanation:
According to chemistry libretexts(2020); "The rms velocity is directly proportional to the square root of temperature and inversely proportional to the square root of molar mass. Thus quadrupling the temperature of a given gas doubles the rms velocity of the molecules. ... As the temperature of a gas is increased, the velocity of the molecules is also increased."
Hence considering two gases for which the Vrms of the particles of one is high and that of the other is low, we can conclude that the gas having the higher Vrms is at a higher temperature than the gas having a lower Vrms according to the foregoing.
How are protons, neutrons, and electrons arranged to form an atom?
Answers
Answer:
Protons are in the middle, electrons are on the loop (outside area) and the neutrons are mixed with the protons.
Explanation:
Answer:
The nucleus (center) of the atom contains the protons (positively charged) and the neutrons (no charge). Atoms are made up of protons and neutrons located within the nucleus, with electrons in orbitals surrounding the nucleus.
Explanation:
how to do question no 17
Answers
Explanation:
even I don't know this answer
but maybe you can solve it by putting the formula
Which of the following is composed of elements combined in a specific ratio?
Answers
Answer:
compound
Explanation:
The diagram illustrates the water cycle.
Parts of the water cycle labeled U through Z. U: Water moving from a lake into the clouds. V: Clouds. W: Water falling from clouds as rain and snow. X: Water moving from ground to the clouds. Y: Water flowing down the mountainside into a lake. Z: Underground water going into lake.
Which process occurs at location W?
precipitation
evaporation
condensation
transpiration
Answers
Answer:
Precipitation
Explanation:
In the water cycle, water experiences different phase changes from one state to another in nature.
The cycling affords water to in solid, liquid and the vapor form.
From the cycle show, W represents precipitation.
During precipitation, water in the atmosphere begins to fall. U is evaporationX is transpiration. V is the condensation.Answer:
precipitation
Explanation:
The equation 2NaNO3 + CaCl2 - 2NaCl + Ca(NO3)2 is balanced. How many atoms
of sodium (Na) are there on either side of the equation?
one
two
four
six
Answers
Answer:3
Explanation:
I took the test
the correct answer is two
Calculate the mass in grams of 0.0035 mol of NaNO3
Answers
Answer:
The Mass in Grams= 0.5145
Explanation:
The atomic mass of Na=23
The atomic mass of No3= 62
we multiply 0.0035×((23×1)+(62×2)) = 0.5145 grams
write the chemical formula of tetraphosporus osctasulfide
Answers
Answer:
P4S8 .
the chemical formula of Tetraphosporus osctasulfide is p4S8
What are the 2 types of electrical charge?
Answers
Answer: Electric charges are of two general types: positive and negative.
Hope this helps... Stay safe and have a great day.... :D
A) A solution of c6h2o4 in c2h5oh has a boiling point of 80.38 Celsius. what is the molality of the solution ?
B) what is the approximation of concentration of dissolved solution in blood, if the osmotic pressure is 7.65 atm at 37Celsius.
Answers
a. molality-m=1.623
b. molarity-M=0.3
Further explanationa. Boiling point
[tex]\tt \Delta Tb=Kb\times m[/tex]
Kb for ethanol=1.22 °C/m
Boiling point for ethanol = 78.4 °C
ΔTb=80.38-78.4=1.98
[tex]\tt 1.98=1.22\times m\\\\m=\dfrac{1.98}{1.22}=1.623[/tex]
b. osmotic pressure
[tex]\tt \pi =MRT[/tex]
π = 7.65 atm
R = 0.08205 L/atm K
T = 37 + 273 = 310 K
[tex]\tt M=\dfrac{\pi}{RT}=\dfrac{7.65}{0.08205\times 310}=0.3~M[/tex]
Three isotopes of argon occur in nature. Calculate the average atomic mass of argon given the following relative atomic masses and abundances of each of the isotopes.
Isotope Relative Atomic Mass Abundance
Ar-36 35.97 amu 0.337%
Ar-38 37.96 amu 0.063%
Ar-40 39.96 amu 99.600%
a
35.97 amu
b
37.95 amu
c
39.95 amu
d
38.96 amu
Answers
Answer:
whats the question
Explanation:
Answer:
Calculate the average atomic mass of argon to two decimal places, given the following relative masses and abundances of each of the isotopes: argon-36 (35.97 amu; 0.337%), argon-38 (37.96 amu; 0.063%), and argon-40 (39.96 amu; 99.600%). ... So the atomic mass of Ar is 0.99639. 96 + 0.0006337. 96 + 0.00337*35.97 = 39.957.
Explanation:
hope this help
What is the new concentration of 25.0mL added to 125.0mL of 0.150M
Answers
Answer:
The new concentration is 0.125 M.
Explanation:
Given data:
Initial volume V₁ = 125.0 mL
Initial molarity M₁ = 0.150 M
New volume V₂ = 25 mL +125 mL = 150 mL
New concentration M₂ = ?
Solution:
M₁V₁ = M₂V₂
0.150 M × 125 mL = M₂ × 150 mL
M₂ = 0.150 M × 125 mL / 150mL
M₂ = 18.75 M.mL/150 mL
M₂ = 0.125 M
The new concentration is 0.125 M.
Titration of a strong acid with a strong base. The pH curve for titration of 50.0 mL of a 0.100 M solution of hydrochloric acid with a 0.100 M solution of NaOH(aq). What volume of NaOH(aq) would be needed to reach the equivalence point if the concentration of the added base were 0.240 M?
Answers
Answer:
Explanation:
we know that M1V1=M2V2
M1=0.100 M
V1=50.0*10^-3 L
M2=0.100 M
V2=M1V1/M2
V2=0.100*50.0*10^-3/0.100
V2=0.05
To know the end point we use phenolphthalein as indicator. End point is a point where completion of reaction happen. The volume of NaOH needed to reach the equivalence point if the concentration of the added base were 0.240 M is 20.8ml.
What is titration?Titration is a technique by which we know the concentration of unknown solution using titration of this solution with solution whose concentration is known.
The balanced equation is
HCl+NaOH[tex]\rightarrow[/tex]NaCl+H₂O
Using following equation
M₁×V₁=M₂×V₂
Where,
M₁=molarity of HCl= 0.100 M
V₁=volume of HCl=50.0 mL
M₂=molarity of NaOH=0.240 M
V₂=volume of NaOH=?
Substituting the given values
0.100 M ×50.0 mL=0.240 M×V₂
V₂=20.8ml
Therefore, the volume of NaOH needed to reach the equivalence point if the concentration of the added base were 0.240 M is 20.8ml.
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The compound F20 has two lone pairs on the central oxygen atom. What's the structure of an F2O molecule? Is this compound polar or non-polar?
A. Trigonal planar, polar
B. Bent or angular non-polar
C. Bent or angular polar
D. Trigonal planar non-polar
Answers
Answer:
Bent or Angular, Polar
Explanation:
I just took the test!
Answer:
C. Bent or angular polar
Explanation:
Of the following compounds, which has the strongest dipole?
Select one:
O a. CCl4
O b. SiO2
OC. PC13
O d. H₂O
O e. Brci
Answers
Answer: D.) H₂O
Explanation:
It can't be A because the molecular geometry is tetrahedral and all the bonding atoms are the same and evenly dispersed, cancels out all dipoles.Can't be B because the molecular geometry is linear and bonding atoms are the same. Therefore the bond dipole cancel out.Can't be C because the molecular geometry is trigonal planar and all the bonding atoms are the same. Therefore all the bond dipoles cancel out.Can't be E because while there is a dipole, it is not as large as the dipole created by an Oxygen Hydrogen bond like the one found in H₂O.Which action is a change in state?
Answers
Dissolving is your answer to this question. Becuase when something dissolves it is no longer in the same shape or state cause if something dissovles then goes away into another state.
Answer: condensing is the correct answer
Explanation:
PLEASE HELP THIS IS DUE TODAY
Answers
Answer:
94.99%
Explanation:
Calcium is an element. What is the smallest particle of calcium that has the same chemical properties of calcium?
A. an atom of calcium
B. a proton from a calcium atom
C. an electron from a calcium atom
D. a molecule that contains calcium
Answers
Answer:
A. An Atom
Explanation:
An atom is the smallest particle of an element, having the same chemical properties as the bulk element.
An atom of calcium is the smallest particle of calcium that has the same chemical properties of calcium.
What is an atom ?An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
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In chemical reaction atoms are what?
Answers
Answer:
In chemical reaction atoms are reactants