Answer:
Electron microscopes differ from light microscopes in that they produce an image of a specimen by using a beam of electrons rather than a beam of light. Electrons have much a shorter wavelength than visible light, and this allows electron microscopes to produce higher-resolution images than standard light microscopes.
Explanation:
Which element has three electron shells and 4 valence electrons?
Silicon
Carbon
Gallium
Argon
Answer: Silicon
Explanation:
For something to have 4 valence electrons, it must be in the 14th column, which elimates gallium and argon for the possible answers. For somethign to have 3 electron shells, it must be in the third row of the periodic table which means the answer is silicon.
Answer:
Gallium
Explanation:
I believe this is the answer if not then the only other option is boron but anyways the answer is Gallium
Chemistry work here. Please help as soon as possible. I have allot of questions that needs to be answered. Can someone do it for me?
Answer:
I dont know about the yield but I think mno2 is the limiting reactant
25 grams of radon-222 remains after 15.28 days. How much radon was in the original sample? Write an equation for the decay of radon-222.
Answer:
half-life = 3.8 days
total time of decay = 15.2 days
initial amount = 100. g
number of half-lives past: 15.2/3.8 = 4 half-lives
4 half-lives = 1/16 remains
100. g x 1/16 = 6.25 g
4. Which of the following demonstrates an organ providing a force?
A. The kidney filters waste from blood.
B. The heart contracts and expands to move blood.
C. he eye transmits information to the brain
D. The skin protects other organs from damage.
Answer:
Um uhhhh um 4d
Explanation:
A molecule has sp3 hybridization with 1 lone pair. The electron pair geometry of this molecule is:________ . The geometry of this molecule is:___________ This molecule will have approximate bond angles of (If more than one bond angle is possible, separate each with a space.):______
Answer:
Tetrahedral
Trigonal pyramidal
less than 109.5°
Explanation:
If a molecule has a hybridization of sp3 it must have four electron domains which corresponds to a tetrahedral geometry.
Now we were told that the molecule also has one lone pair. It means that one out of the four electron domains is composed of a lone pair. Thus the molecular geometry will be trigonal pyramidal (e.g NH3).
Recall that lone pairs usually decrease the bond angle to a value less than the expected value for that particular electron domain geometry.
The expected bond angle for a tetrahedral geometry is 109.5° but that of the trigonal planar geometry is less than this.
d) hydrogen and sulfur
Formed
Answer:
At high temperatures or in the presence of catalysts, sulfur dioxide reacts with hydrogen sulfide to form elemental sulfur and water. This reaction is exploited in the Claus process, an important industrial method to dispose of hydrogen sulfide.
If a stick of dynamite explodes, the
chemical energy changes into what?______________
potential energy, air and clouds
potential energy and physical
energy
kinetic energy, heat and light
Kinetic energy and precipitation
Answer:
kinetic energy, heat and light i'm pretty sure
PLEASE HELP I WILL GIVE 50 POINTS
Step 1: Create your poster.
On the poster board, draw a roller coaster track that starts with one large hill, followed by a valley, and then another, smaller hill.
Draw a cart in four different positions on the track, as outlined below.
First, draw the cart at the top of the first hill. Label it A.
Second, draw the cart going down the first hill, into the valley. Label it B. iii. Third, draw the cart at the bottom of the valley. Label it C.
iv. Last, draw the cart at the top of the second, smaller hill. Label it D.
c) Draw an energy pie chart above each of the cart’s four positions.
Choose your reference point for determining height.
Create a pie chart that accurately represents the ratio of the three forms of energy and label the sections of the pie Eg for gravitational potential energy, Ek for kinetic energy, and Eth for thermal energy.
Answer:
The one above me is correct! I used it. But of course I had to write a little different to the person's sentences and draw a little differently in my own way.
Explanation:
If somehow you can't open the PDF (the comment on top of my comment) here I took a screenshot of it, if you need it! Good luck everyone :D
You have 0.500 L of an 0.250 M acetate buffer solution (i.e. [HC₂H₃O₂] + [C₂H₃O₂⁻] = 0.250 M) at pH 3.50. How many mL of 1.000 M NaOH must you add in order to change the pH to 5.07? Acetic acid has a pKa of 4.74.
Answer:
80mL of 1.00M NaOH
Explanation:
Using H-H equation, we can determine oH of a buffer as acetate buffer. First, we need to determine amount of acetate ion and acetic acid at pH 3.50 and 5.07. Then, with the reaction of NaOH with acetic acid we can find the amount of 1.00M NaOH that must be added:
At pH 3.50:
pH = pka + log [C₂H₃O₂⁻] / [HC₂H₃O₂]
3.50 = 4.74 + log [C₂H₃O₂⁻] / [HC₂H₃O₂]
0.057544 = [C₂H₃O₂⁻] / [HC₂H₃O₂] (1)
Using and replacing in (1):
[HC₂H₃O₂] + [C₂H₃O₂⁻] = 0.250 M
[HC₂H₃O₂] + 0.057544[HC₂H₃O₂] = 0.250 M
1.057544 [HC₂H₃O₂] = 0.250M
[HC₂H₃O₂] = 0.2364M * 0.500L = 0.1182 moles of acetic acid at first pH
At pH 5.07:
pH = pka + log [C₂H₃O₂⁻] / [HC₂H₃O₂]
5.07 = 4.74 + log [C₂H₃O₂⁻] / [HC₂H₃O₂]
2.13796= [C₂H₃O₂⁻] / [HC₂H₃O₂] (1)
Using and replacing in (1):
[HC₂H₃O₂] + 2.13796[HC₂H₃O₂] = 0.250 M
3.13796 [HC₂H₃O₂] = 0.250M
[HC₂H₃O₂] = 0.07967M * 0.500L = 0.0398 moles of acetic acid at first pH
Now, NaOH reacts with HC₂H₃O₂ as follows:
NaOH + HC₂H₃O₂ → NaC₂H₃O₂ + H₂O
As moles of acetic acid decreases from 0,1198 moles - 0,0398 moles = 0,08 moles of acetic acid are consumed = 0,08 moles of NaOH
0,08 mol NaOH * (1L / 1mol) = 0,08L of 1.00M NaOH =
80mL of 1.00M NaOHWhat do we call ingredients in a chemical reaction
Answer:
Reactants or Factors
Explanation:
make the product
What is the formula for Nickel (II) Bisulfate?
Answer:
[tex]NiHSO_{4}[/tex]
Explanation:
We're using nickel with a charge of 2, as indicated by the "(II)" in the name, and bisulfate refers to HSO[tex]_{4}[/tex], which has a charge of 2-, so they are in a 1:1 ratio.
11. Which of the following equations shows a
synthesis reaction?
A
B
C
D
Answer: D
Explanation:
Derive an expression for the molar mass of a gas starting with its density?
Answer:
The relationships between molar mass and density for a monoatomic gas can be easy.
The Ideal Gas Law, PV = nRT can be arranged so that n moles equals the mass/molar mass of the gas to become,
PV =
M
mRT
where m is the mass and M is the molar mass.
M =
PV
mRT
, if you hold the temperature of the gas constant the equation reduces to the Boyle's law or
PV
m
The mass will be constant assuming the container is closed and so the gas cannot be escaped so, PV will be constant.
D =
V
m
and M =
PV
mRT
M =
P
DRT
The higher the density of the gas the higher the molar mass and vice versa.
Explanation:
6.Which of the following is NOT true about the lens?
The following statement which is NOT true about the lens is:
A. It sends light to the optic nerveThe lens is a piece of glass which is used for the dispersal or refraction of light and is used to focus light onto the retina of the eye.
As a result of this, the lens is responsible for refracting of light, focusing of light and it is transparent. However, it does not send light to the optic nerve.
Therefore, the correct answer is option A
Read more here:
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WHo Plays adopt me on Rob.lox tell me what pets you have and tell me your gender
Explanation:
I have a dog in my dog is a girl
Answer:
me
Explanation:
I'm a girl and I have a RIDE skele-rex and a ride cerberus and a n f r GRIFFIN and a f r gold rat and a normal unicorn a RIDE kitsune
Samantha AS
Which of the following compounds is ionic but yet it is expected to
contain covalent bonds as well in the form of a polyatomic ion?
NH3
KBr
CO2
NaF
Fe(NO2)3
Answer:
Fe(NO2)3
Explanation:
A poly atomic ion is an ion that contains more than one atom.
If we look at all the compounds that have been mentioned among the options; KBr and NaF are both ionic but do not contain any covalent poly atomic ion.
However, Fe(NO2)3 contains NO2^+ which is a poly atomic ion that contains the covalent bond.
The original solution used to make the solutions for the standard curve was prepared by dissolving 2.60g of CoCl2 (molar mass 130.g/mol ) in enough water to make 100.mL of solution. What is the molar concentration of the solution?
Answer:
0.200 M
Explanation:
Step 1: Given data
Mass of CoCl₂ (m): 2.60 gMolar mass of CoCl₂ (M): 130 g/molVolume of solution (V): 100 mLStep 2: Calculate the moles (n) of CoCl₂ (solute)
We will use the following expression.
n = m/M
n = 2.60 g/(130 g/mol)
n = 0.0200 mol
Step 3: Convert "V" to liters
We will use the conversion factor 1 L = 1000 mL.
100 mL × 1 L/1000 mL = 0.100 L
Step 4: Calculate the molarity of CoCl₂
We will use the definition of molarity.
[CoCl₂] = n/V(L)
[CoCl₂] = 0.0200 mol/0.100 L
[CoCl₂] = 0.200 M
The molar concentration of the solution is 0.2 M.
First, we must calculate the number of moles of CoCl2 as follows;
Number of moles = mass/molar mass
mass = 2.60g
Molar mass = 130.g/mol
Number of moles = 2.60g/ 130.g/mol = 0.02 moles
Molarity of solution = Number of moles/volume of solution in liters
Volume of solution = 100.mL or 0.1 L
Molarity of solution = 0.02 moles/0.1 L
Molarity of solution = 0.2 M
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Identify an element that is NOT in its standard state.
Choose the one alternative that best completes the statement or answers the question.
A) N2(g)
B) Xe(g)
C) Ca(s)
D) N(g)
Explanation:
Xenon is a gas in its standard state
Calcium is a solid in its standard state
Nitrogen is a gas in its standard state
I am assuming that N2 is a isotope of nitrogen, not sure which but by the process of elimination I think that is the answer
Sketch the graph of y = 4 x squared + 32 x + 15 using your graphing calculator. What are the x-intercepts of this graph? a. (-5, 0) and (3.5, 0) c. There are no y-intercepts b. (-2.5, 0) and (-2, 0) d. (-0.5, 0) and (-7.5, 0) Please select the best answer from the choices provided A B C D
Answer: d.) x= -7.5 x= -0.5
Explanation: correct on edge 2021
The boiling point of an aqueous solution is 101.54 ∘C. What is the freezing point
Answer:
101.54 .C.
Explanation:
How many kJ of heat are needed to completely melt 1.70 moles of H2O, given that the water is at its melting point? The heat of fusion for water is 6.02 kJ/mole.
Answer:
1.70×6.02=6.4414
Explanation:
it would be times
10.2234 kJ of heat is needed to completely melt 1.70 moles of H2O, given that the water is at its melting point and the heat of fusion for water is 6.02 kJ/mole.
What is latent heat?The term "latent heat" refers to the heat energy that a substance retains when its phase changes during a specific process. The latent heat of evaporation, which occurs when a liquid absorbs heat from an external source at its boiling point, is one of many types of latent heat.
Similarly, the latent heat of fusion is used when any substance melt at its melting point to change the liquid phase of that substance.
As given in the problem, The heat of fusion for water is 6.02 kJ/mole. This means 6.02 kJ heat is needed to melt 1 mole of ice into water
Then the heat are needed to completely melt 1.70 moles of H2O,
Heat = 1.70 moles ×6.02 kJ/mole
Heat = 10.2234 kJ
Thus, the heat needed to completely melt 1.70 moles of H2O is 10.2234 kJ
Learn more about Latent heat from here
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Element Z has 2 isotopes. A sample of element Z contains 19% Z234 and 81% Z236. What is the average atomic mass of the element Z?
Answer:
Wt Avg of the two isotopes = 235.62 amu
Explanation:
Given:
abundance
Isotope % fractional mass (amu) Wt. Avg. Contributions
Z234 19% 0.19 234 (0.19)(234) = 44.46 amu
Z236 81% 0.81 236 (0.81)(236) = 191.16 amu
Collective Wt. Avg. of all isotopes = ∑ Wt. Avg. Contributions
= 44.46 amu + 191.16 amu = 235.62 amu
If 42 grams of carbon and 52 grams of oxygen are used, how many grams of CO2 will be produced (Hint: find the
limiting reactant first). SHOW WORK
C + O2 + CO2
Answer:
71.5g
Explanation:
The reaction equation is given as:
C + O₂ → CO₂
Mass of C = 42g
Mass of O₂ = 52g
Unknown:
Mass of CO₂ produced = ?
Solution
Now to solve this problem, we have to find limiting reactant which is the one given in short supply in this reaction.
The extent of the reaction is controlled by this reactant.
Find the number of moles of the given species;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Number of moles of C = [tex]\frac{42}{12}[/tex] = 3.5mol
Number of moles of O₂ = [tex]\frac{52}{32}[/tex] = 1.63mol
Now;
From the balanced reaction equation;
1 mole of C reacted with 1 mole of O₂
We see that C is in excess and O₂ is the limiting reactant.
1 mole of O₂ will produce 1 mole of CO₂
So; 1.63mole of O₂ will produce 1.63 mole of CO₂
Mass of CO₂ = number of moles x molar mass
Molar mass of CO₂ = 44g/mol
Mass of CO₂ = 1.63 x 44 = 71.5g
Mechanical weathering does not change a rock’s
A
shape.
B
size.
C
appearance.
D
composition.
Answer:
C
Explanation:
Answer:
B: Size
Explanation: It can break it into smaller pieces but not change its composition.
the specific heat capacity of titanium is 0.523j/g c what is the heat capacity of 2.3g of titanium
Answer:
1.2029 J/g.°C
Explanation:
Given data:
Specific heat capacity of titanium = 0.523 J/g.°C
Specific heat capacity of 2.3 gram of titanium = ?
Solution:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
1 g of titanium have 0.523 J/g.°C specific heat capacity
2.3 × 0.523 J/g.°C
1.2029 J/g.°C
suppose 2.5g of compound a and 3.5g of compound b are consumed in a reaction that produces only one product compound c
Answer:
Mass of compound c = 6 g
Explanation:
Given:
Mass of compound a = 2.5 g
Mass of compound b = 3.5 g
Find:
Mass of compound c
Computation:
According to Law of conservation of mass
Mass of compound a + Mass of compound b = Mass of compound c
Mass of compound c = 2.5 + 3.5
Mass of compound c = 6 g
A material that consists of only one type of element or compound.
Answer:
Pure substance
Explanation:
A material that consists of only one type of element or compound is regarded as a pure substance.
A pure substance has the following properties;
All the parts are the same throughout i.e. they are homogenousThey have a definite composition. They cannot easily be separated or broken down into simpler substances by physical means. Separation by physical methods is not easyThey have unique sets of properties.Compounds and elements are pure substances too.
If the mass of an object on Earth is 25 kg, what is its weight?
Answer:
250 Newtons.
Explanation:
Weight is a force and the Second Law of Newton can be used to figure out the Force ( weight) of this mass. Since F = ma, and 'a' on Earth is the acceleration due to freefall at 10 m/s^2 ( really 9.8 m/s^2- so your teacher may want your answer as 245 N), you multiply your mass ( 25g ) and your acceleration on Earth and you get 250 N.
What are the other properties of pure substance
Answer:
Characteristics and Properties Of Pure Substances
Pure substances are mostly homogeneous in nature containing only one type of atoms or molecules. These substances mainly have a constant or uniform composition throughout. The substances have fixed boiling and melting points.
Explanation:
they have fixed boiling and melting
hich of the following best describes a person doing science?
A.
Dominick uses a computer to do his math homework.
B.
Lindsay measures the sizes of the craters on the Moon.
C.
Isabel invents a new kind of doorknob.
D.
Murray randomly predicts the result of a coin toss.
Answer:
I think it is answer B. what grade are you in? im in 7th.
Explanation: