Answer:
He discovered the electron - J.J Thompson
He discovered periodic changes in properties of elements when they are listed in order of their atomic weights - Dimitri Mendeleev
He experimented with the deflection of cathode rays by a magnetic field - J.J Thompson
He carried out experiments that measured the scattering of alpha particles by heavy atoms - Ernest Rutherford
His model of the hydrogen atom led to an accurate calculation of the wavelengths of light emitted by an excited hydrogen atom - Neil Bohr
He proposed the planetary model of the atom with most of the mass of the atom concentrated in a very small nucleus - Ernest Rutherford
He modified the planetary model of the atom by suggesting electrons could travel about the nucleus in only a few discrete stable orbits - Neil Bohr
Explanation:
J.J Thompson discovered the electrons. He initially called them cathode rays and he also studied how they are deflected in magnetic fields and by so doing established that they are negatively charged particles.
Ernest Rutherford is renowned for his experiment using the thin gold foil and alpha particles to determine that atoms have a positively charged massive core called the nucleus. This led to the proposition of the planetary model of the atom.
Dimitri Mendeleev discovered periodic changes in properties of elements when they are listed in order of their atomic weights. This led to the discovery of the Mendeleev periodic table.
Neil Bohr model of the atom gave accurate explanation of the emission spectra of the hydrogen atom. His atomic model suggested that electrons could travel about the nucleus in only a few discrete stable orbits.
Answer:
He discovered the electron - J.J Thompson
He discovered periodic changes in properties of elements when they are listed in order of their atomic weights - Dimitri Mendeleev
He experimented with the deflection of cathode rays by a magnetic field - J.J Thompson
He carried out experiments that measured the scattering of alpha particles by heavy atoms - Ernest Rutherford
His model of the hydrogen atom led to an accurate calculation of the wavelengths of light emitted by an excited hydrogen atom - Neil Bohr
He proposed the planetary model of the atom with most of the mass of the atom concentrated in a very small nucleus - Ernest Rutherford
He modified the planetary model of the atom by suggesting electrons could travel about the nucleus in only a few discrete stable orbits - Neil Bohr
Explanation:
Indicate which techniques are appropriate for preparing a dilute solution from a solid.
ACTION ANSWER
When reading the meniscus of a volumetric flask, your eye should be level with the etched line.
The solid should be weighed into a clean, dry beaker. If too much solid is added, the spatula should be used to remove some solid. The removed solid should be considered waste.
If the volumetric flask is over-filled with solvent above the etched line, the solution should be discarded as it is now inaccurate.
Once the solid is dissolved, fill the volumetric flask with solvent until the top of the meniscus is touching the etched line. Preparation is now complete
The solid should be weighed in a beaker and poured into the volumetric flask using a paper funnel.
The solid remaining in the beaker should be rinsed into the waste.
Once solid is dissolved, fill the volumetric flask with solvent until the bottom of the meniscus is touching the etched line. Then mix the solution. Preparation of the solution is now complete.
The solid should be weighed into a clean, dry beaker. If too much solid is added, the spatula should be used to remove some solid and return it to the reagent jar.
Answer:
When reading the meniscus of a volumetric flask, your eye should be level with the etched line.
If the volumetric flask is over-filled with solvent above the etched line, the solution should be discarded as it is now inaccurate.
Once solid is dissolved, fill the volumetric flask with solvent until the bottom of the meniscus is touching the etched line. Then mix the solution. Preparation of the solution is now complete.
Explanation:
When preparing a solution of a solid, the solid must be accurately weighed. After the solid is weighed, it is now carefully transferred to the volumetric flask.
The person preparing the solution must ensure that his/her eyes is at the same level as the flask. In event of adding water above the etched line. The solution must be discarded because it has exceeded the required concentration.
Once the solid has been transferred to the flask, water is added until the bottom of the meniscus is touching the etched line. The solution is now mixed and preparation of the solution is now complete.
The ground below your feet moves at the rate at which... Look at the picture.
Answer:
i dont know
Explanation:heheheheh
What’s the difference between nonrenewable and renewable energy sources? Is biomass a renewable energy source?
Answer:
Yes, biomass is a renewable energy source
Explanation:
Biomass—renewable energy from plants and animals
Nonrenewable energy resources, like coal, nuclear, oil, and natural gas, are available in limited supplies. Renewable resources are replenished naturally and over relatively short periods of time.
Answer:
Explanation:
Nonrenewable energy resources, like coal, nuclear, oil, and natural gas, are available in limited supplies while renewable resources are replenished naturally and over relatively short periods of time. Yes, Biomass is renewable organic material that comes from plants and animals.
Classify each chemical reaction:
reaction
1. CH3CH2OH(f) → 3O2g + 2CO2 + 3H2Og
a. combination
b. precipitation
c. single replacement
d. combustion
e. double replacement
f. acid-base decomposition
2. MgI2 (aq) + Pb(NO3)2(aq) → Mg(NO3)2(aq) + PbI2(s)
a. combination
b. precipitation
c. single replacement
d. combustion
e. double replacement
f. acid-base decomposition
3. 16Ks + S8s → 8K2 + Ss
a. combination
b. precipitation
c. single replacement
d. combustion
e. double replacement
f. acid-base decomposition
4. CH4g + 2O2g → CO2g + 2H2Og
a. combination
b. precipitation
c. single replacement
d. combustion
e. double replacement
f. acid-base decomposition
Answer:
1) combustion
2) double replacement
3) combination
4) combustion
Explanation:
The combustion of a compound refers to the reaction of that compound with oxygen to produce heat and light. In reactions (1) and (4) above, ethanol and methane reacted with oxygen to yield carbon dioxde and water. This is a combustion reaction.
Reaction(2) is a double replacement reaction because the both cations exchange their anion partners in the product.
Reaction (3) is a combination reaction. It involves the joining of two elements to form a new compound.
The unit cell for tin (Sn) has tetragonal symmetry, with a and b lattice parameters of 0.583 and 0.318 nm, respectively. If its density, atomic weight, and atomic radius are 7.30 g/cm3, 118.69 g/mol, and 0.151 nm, respectively. Determine its atomic packing factor.
Answer:
0.1334
Explanation:
The number of atoms per unit (n) is given by:
[tex]n=\frac{\rho a^2bN_a}{A} \\\\where\ a=5.83*10^{-8}cm,b=a=3.18*10^{-8}cm,\rho=7.3\ g/cm^3,\\N_a=Avogadro\ number=6/022*10^{23} mol^{-1},A=atomic\ weight\\=118.68 \ g/mol\\\\n=\frac{7.3* (5.83*10^{-8})^2*(3.18*10^{-8})*6.02*10^{23}}{118.69}\\\\n=4\ atoms/unit[/tex]
The atomic packing factor (APF) is:
[tex]APF=\frac{n(\frac{4\pi R^3}{3} )}{a^2b} \\\\But\ R=atomic\ radius=1.51*10^{-8}\ cm\\\\APF=\frac{4(\frac{4\pi (1.51*10^{-8})^3}{3} )}{(5.83*10^{-8})^2*3.18*10^{-8}}\\\\APF=0.1334[/tex]
Question 1/20
> NEXT
BOOKMARK
Q
1
The process by plant cells to use sunlight to create glucose is called Photosynthesi, cellular, active, passive, or osmosis
Answer:
PHOTOSYNTHESIS
Explanation:
Photosynthesis is the process by which plant take in Carbondioxde and water in the present of sunlight in order to produce glucose and oxygen
24 * All the following hormones help in the appearance of beard in the adult male,
except
Answer:21
Explanation:sadadasdasdad
Answer:
Facial hair growth is largely propelled by testosterone, a hormone. Testosterone levels can vary. For men between 19 and 38, the normal range is 264 to 916 nanograms per deciliter
What is the biggest difference between thermal energy and temperature?
Answer:
Heat deals more with thermal energy whereas temperature deals with molecular kinetic energy.
True or False: In a graph the independent variable will always go on the side.
A.True
B.False
Answer:
False, the independent variable goes on the bottom
The statement “In a graph, the independent variable will always go on the side.” is false. The correct option is B.
What is a graph?A graph is a simple way of representing data. It shows the relation between two or more data with lines, numbers, and charts. The mathematical graphs are of different types. Mainly, a graph has a line and an x-axis and y-axis.
The x-axis contains the independent variable, which is written n the bottom of the graph, horizontally. The y-axis contains the dependent variable, which is written on the left side of the graph vertically.
The independent variable change, but the dependent variable do not change. It is the input. The independent variable changes with the time or what is written on the dependent variables.
Thus, the correct option is B. False.
To learn more about graphs, refer to the link:
https://brainly.com/question/24378069
#SPJ6
Plz help me I Am timed plz
Which of the following is an example of a nonrenewable resource?
OA) water
OB) grass
C) soil
D) trees
Answer:
D) Trees
Explanation:
I'm sure its trees, because once you cut all trees you cant regenerate, or replenish them. hope im right, sorry of its wrong!!
What type of particle has no mass or charge?
A) Alpha
B) Beta
C) Gamma
D) Proton
Answer:
Your answer would be C.
Explanation:
Gamma radiation, unlike alpha or beta, does not consist of any particles, instead consisting of a photon of energy being emitted from an unstable nucleus. Having no mass or charge, gamma radiation can travel much farther through air than alpha or beta, losing (on average) half its energy for every 500 feet.
Gamma particles has no mass or charge.
What are gamma radiations?Gamma radiations is a kind of radiations, which are emitted during a nuclear reaction. Gamma radiations are emitted in the form of photons of energy, they did not carry any particles like alpha, beta and proton. So, because of not carrying any particle this radiations have no mass and as it is on the form of energy they also do not carry any charge.
Hence, the particles which has no mass or charge is gamma.
To learn more about gamma radiations, visit the below link:https://brainly.com/question/20799041
7. Which substance is an element?
Owater
O Oxygen
O petroleum
O carbon dioxide
Oxygen
hope that helped.
If 0.200 moles of NO are produced, how many moles of copper (I) nitrate produced?
A student says that since the atomic theory is just a theory, it should not be considered useful. Which statement best argues against the student's opinion? (2 points) Scientific theories change over time. Scientific theories are the results of many experiments and observations. Scientists often do not agree about specific details of scientific theories. Scientists often propose competing theories. Scientific theories do not become Scientific Laws.
Answer:
Scientific theories are the results of many experiments and observations.
Explanation:
I think this is ti sorry if I'm wrong :|
Please help asap! Brainliest to correct answer.
What is the volume of 2.1 moles of nitrogen gas at standard temperature and pressure (STP)?
Select one:
a. 11 L
b. 22 L
c. 47 L
d. 82 L
Answer:
47 L will be the volume STP
Explanation:
pls help I’ll give allot of points I need all the answers pls anybody help!!!
Which of the following statements is NOT true about practice?
assume that the density of all solutions are 1.000g/ml 1. Calculate the molarity of calcium in 1.9g of calcium chloride diluted in 100 ml of Di water. 2 Calculate the concentration of both calcium and chloride lons in problem 1 in units of mg/mL, ug/L, mg/L and ug/mL. 3. Calculate the concentration of both calcium and chloride ion in problem 1 in units of ppm and ppb. You may assume that the density of the solution is 1.0 g/ml 4. You have been provided 100 ml of a 1000 ug/ml barium standard. What volume of this standard must be diluted to a final volume of 50 ml using DI water to produce a 30 ug/mL standard
Answer:
1. 0.1712M
2. 6.86mg/mL Ca, 12.14mg/mL Cl, 6860000ug/L Ca, 12140000ug/L Cl, 6860mg/L Ca, 12140mg/L Cl, 6860ug/mL Ca, 12140ug/mL Cl.
3. 6860ppm Ca and 12140ppm of Cl.
4. 1.5mL of the 1000ug/mL barium standatd must be taken.
Explanation:
1. Molarity is defined as the amount of moles of solute (Calcium chloride) present in 1L of solution.
The moles of CaCl₂ are:
1.9g CaCl₂ * (1mol / 110.98g) = 0.01712 moles
In 100mL = 0.10L:
0.01712mol / 0.10L = 0.1712M
2. The masses of Calcium and Chloride ions are:
1.9g * (40.078g Ca / 110.98g) = 0.686g Ca
And:
1.9g - 0.686g Ca = 1.214g Cl
mg/mL:
686mg Ca / 100mL = 6.86mg/mL Ca
1214mg Cl / 100mL = 12.14mg/mL Cl
ug/L:
686000ug / 0.1L = 6860000ug/L Ca
1214000ug/ 0.1L = 12140000ug/L Cl
mg/L:
686mg Ca / 0.1L = 6860mg/L Ca
1214mg Cl / 0.1L = 12140mg/L Cl
ug/mL:
686000ug Ca / 100mL = 6860ug/mL Ca
1214000ug Cl / 100mL = 12140ug/mL Cl
3. ppm are defined as mg/L, the ppm of Ca are 6860ppm Ca and 12140ppm of Cl
4. The solution must be diluted from 1000ug/mL to 30ug/mL, that is a dilution of:
1000ug/mL / 30ug/mL:
33.33 times must be diluted the solution.
As final volume of the diluted solution must be 50mL, the volume of the standard needed is:
50mL / 33.33 times = 1.5mL of the 1000ug/mL barium standatd must be taken
1. Making coffee or tea requires hot water to remove soluble components from the grounds or leaves. This is a separation process called extraction, removing a soluble component from solid material. What other separation technique is used to prepare the coffee or tea to drink
Answer:
The other technique which used to separate the coffee or tea is Filtration.
Filtration is a physical, biological or chemical operation that separates solid matter and fluid from a mixture with a filter medium that has a complex structure through which only the fluid can pass.
Solid particles that cannot pass through the filter medium are described as oversize and the fluid that passes through is called the filtrate.
During burning, elements in the coal are
converted to compounds called ?
During burning, elements in the coal are converted to compounds called oxides.
An oxide is a compound formed by combination of an element with oxygen. Usually, when an element is burnt in oxygen, it combines with oxygen in the presence of heat to form oxides.
Coal contains carbon, nitrogen and sulfur. When coal is burnt, these elements combine with oxygen to form oxides. The products of combustion of coal are oxides of sulfur, oxides of carbon and oxides of nitrogen.
Learn more: https://brainly.com/question/2673886
Cell walls provide shape and structure in plant cells.
True or False?
Answer:
Plant cells are surrounded by a cell membrane and outside this is a fairly rigid cell wall. The cell wall gives the plant cell a more definite shape than an animal cell. Animal cells do not have a cell wall.
Explanation:
True because It is flexible, but provides strength to the cell which helps protect the cell against physical damage. It also gives the cell its shape and allows the organism to maintain a certain shape o
Earth systems can interact quickly or over long periods of time. Give an example of how Earth can change quickly and an example of how it changes slowly. Describe how Earth's systems interact in these changes.
Answer:
Earth is made of several subsystems or "spheres" that interact to form a complex and continuously changing whole called the Earth system. to thousands of kilometers, and on time scales that range from milliseconds to billions of years of the Earth; earthquake; Examples of long term - making coal; plate tectonics
Explanation:
A red blood cell is placed into each of the following solutions. Indicate whether crenation, hemolysis, or neither will occur. Solution A: 2.37 % (m/v) NaCl Solution B: 0.59 % (m/v) glucose Solution C: distilled H2O Solution D: 9.39 % (m/v) glucose Solution E: 5.0% (m/v) glucose and 0.9% (m/v) NaCl
Answer:
A: 2.37 % (m/v) NaCl Solution: crenation.
B: 0.59 % (m/v) glucose Solution: hemolysis.
C: distilled H2O Solution: hemolysis.
D: 9.39 % (m/v) glucose Solution: crenation.
E: 5.0% (m/v) glucose and 0.9% (m/v) NaCl: neither.
Explanation:
A red blood cell should be placed in an isotonic solution to avoid crenation or hemolysis. An isotonic solution has the same solute concentration as the one in the interior of the cell. As a result, the solvent does not have to move toward the place with a higher solute concentration to balance it.
When the red blood cell is in a solution that has a higher concentration of solutes than the one inside the cell, in other words, the cell is in a hypertonic solution. The solvent will flow from the cell to the solution causing a crenation of the cell.
When the red blood cell is in a solution with a lower solute concentration than the one inside the cell, also known as a hypotonic solution. The solvent will flow from the outside to the inside of the cell. As a result, the cell suffers hemolysis.
The isotonic solution for the cell should be 5.0% (m/v) glucose and 0.9% (m/v) NaCl, to avoid crenation or hemolysis.
Writing Sample: At what pressure would 0.150 mole of nitrogen gas at -23.0 o C occupy 8.90 L?
Answer:
[tex]P=0.346atm[/tex]
Explanation:
Hello!
In this case, since the ideal gas equation is:
[tex]PV=nRT[/tex]
And we are asked to compute the pressure, we obtain:
[tex]P=\frac{nRT}{V}[/tex]
Thus, since the temperature must be expressed in Kelvins, we plug in to obtain:
[tex]P=\frac{0.150mol*0.08206\frac{atm*L}{mol*K}*250.15K}{8.90L}\\\\P=0.346atm[/tex]
Best regards!
Which part of the landscape shown in this image is the steepest?
Answer: A I believe
Explanation:
What type of element would form an ionic bond with iodine?
1. metalloid
2. solid
3. metal
4. nonmetal
What type(s) of orbital overlap is(are) used to form the indicated bond in the following structure.
H H
\ /
C --- C O --- H
// \\ |
H --- C C --- C --- H
\ / |
C == C H
/ ↑ \
H H
A. sp3-s
B. sp2-s
C. sp2-sp2 (I chose C but it is incorrect)
D. sp3-sp2
E. sp3-sp3
F. p=p orbitals
In a coffee cup calorimeter, 1.60 g of NH4NO3 is mixed with 75.0 g of water at an initial temperature of 25.008C. After dissolution of the salt, the final temperature of the calorimeter contents is 23.348C. Assuming the solution has a heat capacity of 4.18 J 8C21 g21 and assuming no heat loss to the calorimeter, calculate the enthalpy change for the dissolution of NH4NO3 in units of kJ/mol.
Answer: ΔH for the dissolution of [tex]NH_4NO_3[/tex] is +26.0205 kJ/mol
Explanation:
The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.
[tex]Q=m\times C\times \Delta T[/tex]
Q = Heat released by solution = ?
C = heat capacity = [tex]4.18J/g^0C[/tex]
Initial temperature of water = [tex]T_i[/tex] = [tex]25.008^0C[/tex]
Final temperature of water = [tex]T_f[/tex] = [tex]23.348^0C[/tex]
Change in temperature ,[tex]\Delta T=T_f-T_i=(23.348-25.008)^0C=-1.66^0C[/tex]
Putting in the values, we get:
[tex]Q=75.0g\times 4.18J/g^0C\times -1.66^0C=-520.41 J[/tex]
As heat released by water is equal to heat absorbed by dissolution of [tex]NH_4NO_3[/tex]
[tex]\text{Moles of}NH_4NO_3=\frac{\text{given mass}}{\text{Molar Mass}}=\frac{1.60g}{80g/mol}=0.02mol[/tex]
Enthalpy change for 0.02 moles of [tex]NH_4NO_3[/tex] = 520.41 J
Enthalpy change for 1 mole of [tex]NH_4NO_3[/tex] = [tex]\frac{520.41}{0.02}\times 1=+26020.5J=+26.0205kJ[/tex]
ΔH for the dissolution of [tex]NH_4NO_3[/tex] is +26.0205 kJ/mol
One mole (mol) of ethanol (C2H60) has a mass of 46.0684 g.
How many moles of ethanol are in an 18.0 g sample?
Need to see how the calculation was done.
Answer:
the number of moles of ethanol is 18 g sample is 0.390 mol
Explanation:
The computation of the number of moles of ethanol is 18 g sample is shown below:
= Mass of ethanol sample ÷ molar mass of ethanol
= 18 g ÷ 46.064=84 g
= 0.390 mol
Hence, the number of moles of ethanol is 18 g sample is 0.390 mol
How many grams of carbon dioxide (CO2) are produced from the combustion of 13.00 g of CH4?
Answer:
35.68g CO2
Explanation:
we use the combustion equation with CH4:
CH4+ O2= CO2 + H2O
And then balance it:
CH4+ 2O2= CO2 + 2H2O
Using this equation we can use sociometry:
[tex]13g CH4*\frac{1molCH4}{16.032gCH4} *\frac{1mol CO2}{1molCH4} *\frac{44g CO2}{1mol CO2}=35.68g CO2[/tex]
We know that 16.032 is how many grams there are in one mole of CH4 by adding the weights of the atoms (12 +1.008+1.008+1.008+1.008). These weights can be found on the periodic table. The same goes for the amount of grams per CO2.
The important thing about sociometry is to make sure your units cancel out until you are only left with the unit you want. If grams of CH4 is in the numerator, the next fraction you multiply by should have grams of Ch4 in the denominator. If moles of CO2 are in the numerator, the next fraction should have moles of CO2 in the denominator.