Answer:
15 sec
Explanation:
1. How many valence electrons does lodine
have?
Can sedimentation and decantation be used for all types of mixtures? Explain
Is there a relationship between the mass of an object and the rate of settling? Explain.
Explanation:
1. Sedimentation and decantation cannot be used for all types of mixtures.
Decantation is a separation technique in which is used to separate immiscible liquids or mixtures containing liquid and solids within them.
In decantation, gravity is used to bring the denser materials to settle at the bottom.
For homogenous mixtures, it is not possible to use decantation. A solution of sugar and water will not decant.
2. Yes, mass of an object reduces the settling time of such object in a mixture.
The higher the mass, the faster the rate of settling. Also, as we know, mass is directly proportional to density. A body with a high density will settle faster in solution.
Someone knows how to solve this? It was found that 0.0005 mol of Ca (OH) 2 dissolved in 100 cm3 of solution is 80% dissociated. Calculate the pH of this solution.
Answer:
pH = 11.9
Explanation:
First, we determine the number of OH⁻ moles dissolved:
80% of Ca(OH)₂ is dissolved:
0.0005 mol * 80/100 = 4x10⁻⁴ mol Ca(OH)₂There are two OH⁻ moles per Ca(OH)₂ mol:
4x10⁻⁴ * 2 = 8x10⁻⁴ mol OH⁻Now we can calculate the molar concentration of OH⁻ (moles/L):
100 cm³ = 100 mL100 mL ⇒ 100/1000 = 0.1 L[OH⁻] = 8x10⁻⁴ mol / 0.1 L = 8x10⁻³ MThen we calculate the pOH of the solution:
pOH = -log[OH⁻] = -log(8x10⁻³ M) = 2.10Finally, we can calculate the pH of the solution using the equation
pH + pOH = 14pH = 14 - pOH = 14 -2.10pH = 11.9Which element would have chemical reactions most similar to fluorine (F)?
A. O
B. Br
C. Ne
D. Fm
giving brainliest if right
[tex]\mathrm {Hey, there!}[/tex]
The answer is: Bromine
Oxygen is not similar to flourine, it is not a noble gas with high ionization.
Neon does not have chemical reactions like flourine.
The answer is Bromine! Best of Luck!
Answer:
Br
Explanation:
Which of the following trends decrease down group 1 from Li → Cs?
I. melting point
II. jonization energy
III. atomic radius
A.
I and II only
B.
II and III
C.
II and IIl only
D.
I and III only
Answer:
A. I and II only
Explanation:
As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.
As the size of atom increases the ionization energy from top to bottom also decreases because it becomes easier to remove the electron because of less nuclear attraction and as more electrons are added the outer electrons becomes more shielded and away from nucleus.
Melting point also goes to decreases because there is large distance between the positive nucleus and bonded electrons thus overall attraction goes to reduced and less energy is required to melt.
What is the Molecular mass of sodiumcholoride ?
Answer:
58.5g/mol
Explanation:
Given substance:
Sodium chloride = NaCl
Unknown:
Molecular mass = ?
Solution:
The molecular mass of a compound is the gram-formula mass or gram-molecular weight of the compound.
It is determined by adding its component atomic masses and then express in grams per mole;
Atomic mass of Na = 23g
Atomic mass of Cl = 35.5g
NaCl = 23 + 35.5 = 58.5g/mol
True or False;
aa is faster moving lava than pahoehoe?
Answer:
It is false :l
Explanation:
Pahoehoe is a smooth and continuous lava crust. Pahoehoe forms when the effusion rate is low and consequently the velocity of lava flow is slow. Pahoehoe lava flow is usually at least 10 times slower than typical aa lava flow.
:/
HELP PLEASE ANSWER ASAP!!!!!
When atoms react, they often lose, gain, or share electrons to form a more stable version of themselves. For example, alkali metals such as sodium (Na) lose their outer shell electron in their reactions to form compounds. The electron configuration of alkali metals would then resemble those of which group of the periodic table in the compounds they form?
a. 7A or group 17
b. 8A or group 18
c. 2A or group 2
d. 1A or group 1
Answer:
D
Explanation:
Calculate the number of moles in 7g of nitrogen gas
Answer:
0.2498mol[tex]N_{2}[/tex]Explanation:
7gN2 x [tex]\frac{1 mol}{2(14.01) g}[/tex]
=0.2498mol N2
Nitrogen gas has the formula [tex]N_{2}[/tex] so therefore that means you would have to multiply the mass in the molar by 2. To solve for the number of moles you need to cancel out the grams, you do this by using the molar mass of nitrgoen gas. You get the value on in the denominator from the periodic table (atomic mass of element). The grams will cancel out, leaving you with the number of moles when you divide 7/2(14.01).
Which term refers to the ability to do work? O energy O power force O motion
Please I have a 50 question Exam
Answer:
the correct answer in energy
Explanation:
The term refers to the ability to do work is energy. The correct option is A.
What is energy?Energy is the quantitative property that is required by the body to do some work. It is a conserved quantity, but can not be created or destroyed.
Animals and plants get energy from food.
Thus, the correct option is A. energy.
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Dry ice is a form of carbon dioxide that sublimates at room temperature. At a Halloween party, some students noticed that the dry ice underwent a phase change. Which statement below best describes the change in the energy and physical characteristics of the molecules of carbon dioxide during this process?
A. The molecules experienced a physical change from a gaseous state to a liquid state, releasing energy into the environment and reducing the molecular movement.
B. The molecules experienced a chemical change as the carbon dioxide reacted with oxygen, which released oxygen gas into the environment and increased the molecular movement.
C. The molecules experienced a physical change from a solid state to a gaseous state, which increased the molecular movement and the energy of the carbon dioxide molecules.
D. The molecules experienced a chemical change from a liquid state to a solid state, which reduced the amount of energy between the carbon dioxide molecules and decreased the molecular movement.
Answer:
The molecules experienced a physical change from a solid state to a gaseous state, which increased the molecular movement and the energy of the carbon dioxide molecules
brainliest
The statement which best describes the change in the energy and physical characteristics of the molecules of carbon dioxide during this process is (B) The molecules experienced a chemical change as the carbon dioxide reacted with oxygen, which released oxygen gas into the environment and increased the molecular movement.Hence, The correct option is (B)
What is Physical Change ?Physical changes are those that affect a chemical substance's form but not its chemical content.
Physical changes may normally be used to separate compounds into chemical elements or simpler compounds, but they cannot be used to separate mixtures into their component compounds.
A change in physical attributes accompanies a physical change. Melting, turning into a gas, and changing strength are a few examples of physical qualities.
Therefore, molecules of carbon dioxide during this process is (B) The molecules experienced a chemical change as the carbon dioxide reacted with oxygen, which released oxygen gas into the environment and increased the molecular movement.Hence, The correct option is (B)
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27. The fundamental SI unit of length is the meter. How-
ever, we often deal with larger or smaller lengths or
distances for which multiples or fractions of the fun-
damental unit are more useful. For each of the fol-
lowing situations, suggest what fraction or multiple
of the meter might be the most appropriate mea-
surement.
a. the distance between Chicago and Saint Louis
b. the size of your bedroom
c. the dimensions of this textbook
d. the thickness of a hair
Answer:
A) Km
B) m
C) cm
D) mm
Explanation:
A) The distance between Chicago and Saint Louis is quite a distance and would be best presented in the largest multiple of the SI unit of length.
For example if the distance is 500000 m, it's a bit bogus to write, so we can simplify by writing in terms of 10^(-3) m which is in km.
Thus, we can write as 500000 × 10^(-3) km = 500 km
B) By standard measurement, the size of a bedroom is usually: 3.6 m × 3.6 m.
This not complex to write and can be kept as it is in metres.
C) The average dimension of a textbook is around 0.25 m by 0.2 m.
Let's get rid of the decimal by converting to terms of 10² m which is expressed as cm.
Thus, dimension is now: (0.25 × 10²) by (0.2 × 10²) = 25 cm by 20 cm
D) Average thickness of a hair in metres is 8 × 10^(-5) m.
Now this is a bit long. So we can express is in terms of 10^(3) m which is an expression denoted by millimeter (mm).
Thus, thickness is 8 × 10^(-5) × 10³ = 0.08 mm
Why is it that no two elements have the exact same emission spectrum?
Answer:
When atoms are excited they emit light of certain wavelengths which correspond to different colors. Each element produces a unique set of spectral lines. Since no two elements emit the same spectral lines, elements can be identified by their line spectrum.
Explanation:
Potassium cyanide is a toxic substance, and the median lethal dose depends on the mass of the person or animal that ingests it. The median lethal dose of KCN for a person weighing 215 lb (97.5 kg ) is 8.84×10−3 mol .
What volume of a 0.0250 M KCN solution contains 8.84×10−3 mol of KCN?
Express the volume to three significant figures and include the appropriate units.
Answer:
0.354L
Explanation:
Given parameters:
Molarity of KCN = 0.025M
Number of moles = 8.84 x 10⁻³mol
Unknown:
Volume of KCN = ?
Solution:
The molarity of a substance is expressed as;
Molarity = [tex]\frac{number of moles }{volume }[/tex]
Volume of KCN = [tex]\frac{number of moles }{molarity}[/tex]
Now insert the parameters and solve;
Volume of KCN = [tex]\frac{0.00884}{0.025}[/tex] = 0.354L
Suppose someone claims they have invented a new automobile engine that can produce more energy than is found in the fuel used to run it. Apply scientific principles to evaluate the person's claim.
Answer:
See explanation
Explanation:
According to the second law of thermodynamics, the conversion of energy from one form to another is never hundred percent efficient. Some energy is always lost as energy is transformed from one form to another.
When a fuel is used to run an automobile engine, chemical energy from the fuel is converted into to the mechanical energy of the automobile. This energy conversion can never be hundred percent efficient in accordance with the laws of thermodynamics. Some energy is always lost as heat.
Hence, the engine does not even efficiently convert all the chemical energy available in the fuel. Therefore, it is impossible to find an automobile engine that can produce more energy than the fuel used to run it.
The formula for calculating density, D, is D=MV, where M represents mass and V represents volume. For liquids, volume is often given in cubic centimeters (cc), which is the same as cm 3. If the density of an unknown liquid is 1.6 g/cc, what is the mass of 800 cc of the unknown liquid in grams (g)? 0.002 g 1.6 g 500 g 1280 g
please anwser asap!!!!!!!
Answer:
500g
Explanation:
Just divide by all the numbers and the one that equals 1.6 is the answer
What determines the appearance of the moon from earth?
To solve this we must be knowing each and every concept related to satellite. Therefore, moon phases and moon placements have a role the appearance of the moon from earth.
What is satellite?Any object that circles a planet in a curved route is considered a satellite. There are several man-made (manufactured) satellites, most of which are closer to Earth than the moon, which is Earth's original natural satellite.
We must revisit our buddy Newton in order to comprehend why satellites move in this manner. Gravity, according to Newton, is a force that unites all of the universe's objects. Moon phases and moon placements have a role in determining this. The only major factor affecting the Moon's phase is where it is in relation to Earth and the Sun.
Therefore, moon phases and moon placements have a role the appearance of the moon from earth.
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How many moles are in 68 grams of copper (II) hydroxide, Cu(OH)2
heres your answer mate...
When you have been swimming and you come out of the pool, you may feel cold. Use your understanding of endothermic processes to explain why?
Answer:
An endothermic process is any process with an increase in the enthalpy H (or internal energy U) of the system. In such a process, a closed system usually absorbs thermal energy from its surroundings, which is heat transfer into the system.
HELP ME PLEASEEEEEEEEEEEEEEE
(I really dont know the subject i just know science)
Answer:
B
Explanation:
weight , w= mg where m is the mass of the object (unit is kg ) and g is the gravitational force acting on the object ( unit is m/s^2 )
hope it helps
The diagram below shows an oxygen molecule formed when two oxygen atoms bond. Which is likely to be the nature of bonding formed?
Answer:
Covalent bonding
Explanation:
covalent bonding
Which is the best example and explanation that a physical change has occurred?
What is the energy of the photons of a laser with a frequency of 5.75 x 10^12 Hz? (Hint: Remember to round your answer to the lowest number of significant figures.)
Planck's Constant =6.626 X 10^-34
Energy of a photon = Plancks constant x Frequency
Answer:
E = 3.81×10 ⁻²¹ J
Explanation:
Given data:
Frequency of photon = 5.75 ×10¹² Hz
Plancks constant = 6.626 ×10⁻³⁴ Js
Energy of photon = ?
Solution:
E = h×f
E = 6.626 ×10⁻³⁴ Js × 5.75 ×10¹² s⁻¹
E = 38.1×10 ⁻²² J
E = 3.81×10 ⁻²¹ J
which of the following is an oxyanion?
Answer:
please give the answer choice.
what type of a solid contains particles that are jumbled and form no particular pattern?
a. high-pressure
b. high-viscosity
c. crystaline
d, amorphous
Amorphous solids have two characteristic properties. When cleaved or broken, they produce fragments with irregular, often curved surfaces; and they have poorly defined patterns when exposed to x-rays because their components are not arranged in a regular array. An amorphous, translucent solid is called a glass
observe the long-term effects OT erosion on
1.
Click Play ( )). Wait for about 20,000 simulated years, then click Pause ( 1 ). If you want,
you can drag the landscape to rotate the view. How much does the landscape change?
Several erosive agents affect the soil structure and composition. Selecting sandstone, 100cm/yr precipitation, 20ºC, and 50% vegetation cover, there is 45% of eroded rock. The general landscape appearance changes little.
ErosionErosion is the process of fertile soil loss.
It is due to several external agents that damage the ground and drag the exposed material from the superficial layer of the earth.
Erosive agents
Some of the erosive agents are water, wind, ice, gravity, or animal trampling.
Phases
Three main phases compose the erosion process
a) particles landslide
b) transport of superficial free particles
c) deposit/sedimentation.
Soil erosion leads to its degradation.
Since its regeneration is extremely slow, erosion produces several negative events that lead to soil loss as a non-renewable natural resource.
Vegetation cover
All the erosive agents act together modifying the soil composition, shape, and structure. The loss of plant cover increases, even more, the erosive effects.
Soil vegetation cover reduces erosion because the aerial part of the plant protects the surface, while roots protect the ground structure and retain water.
The less vegetation cover there is, the more exposed the soil is, and the more severe effects the erosive agents cause.
In the exposed example, we have many variables to control and analyze their effect on soil erosion. Before playing the simulation, I chose the followings
Stones ⇒ sandstone Precipitation ⇒ 100 cm/yrTemperature ⇒20 ºCVegetation cover ⇒ 50%Under these conditions, after 20,000 years there was 0.42 km³ of eroded rock.
The general aspect of the landscape changed very little, suggesting that erosion occurs slowly.
Probably, if we change the values of the variables, we will observe a sharper change. For instance, if we take the vegetable cover to less than 20% and increase the levels of precipitation and temperature, we will observe a faster erosion process and a wider affected area.
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Which of these are significant problems with bottled water?
Immense plastic use
Fossil fuel used to transport water
Water bottles can leach toxics into water
All of the above
Answer:
All the above
Explanation:
All the above
which atom or ion is the largest?
A. K
B. K^+
C. Ca
D. CA^2+
E. Li
Answer:
A
Explanation:
A 1.5 m block of tungsten has a mass of 28 875 kg.
Write down the equation that links density, mass and volume.
Explanation:
Density is an intensive property of any matter. Any given pure sample of a substance will have the same density value.
Density is the mass per unit volume of a compound;
Mathematically;
D = [tex]\frac{M}{V}[/tex]
where M is the mass
V is the volume
D is the density
3.04 Quiz: Chemical Reactions
Word bank please help fill.
Answer:
1. Chemical reactions
2.Substances
3. Properties
4. Precipitate
5. Light
6. Temperature
7. Color
8. Gas
Explanation:
During chemical reactions, new substances that possess new properties are formed. During the process of chemical reactions, evidences are found. Some of the evidences are formation of precipitate or light gel, production of gases and changes in colour and temperature.
Chemical reactions start with the substances or compounds which are known as reactants. The reactants react to form new substances known as the products which possess new properties.