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which of the following flouride has the highest lattice energy a)NaF b)KF c)CsF d)LiF
Answers
Answer:
The correct option is;
d) LiF
Explanation:
The Lattice energy of ionic compounds can be calculated using the modified Coulomb's law as follows;
[tex]U = \dfrac{k' \cdot Q_1\cdot Q_2}{r_0}[/tex]
Where;
Q₁ and Q₂ = The ionic charges
k' = A constant depending on the ionic and valence configuration
r₀ = The distance between the two nucleus
Given the four compounds each of the metallic ions are of the same group (group one) have the same (only one) valence electron, and are combined to the same ion (fluoride ion) such that Q₂, is the same for all compounds, the factor that will influence the lattice energy more will be the r₀
The sizes of the atoms Li, Na, K and Cs increases as arranged as such Li has the least r₀, and therefore LiF the least lattice energy
From chemistry test online, we have;
The lattice energy of LiF = -1045 kJ/mole
The lattice energy of NaF = -924 kJ/mole
The lattice energy of KF = -822 kJ/mole
The lattice energy of CsF = -737 kJ/mole.
If each geometric shape represents a different type of atom, and atoms that are touching have chemically bonded with each other, which best describes this model? * 1. An element 2. A compound 3. A homogeneous mixture of two compounds 4. A heterogeneous mixture of two compounds 5. A homogeneous mixture of four elements 6. A heterogeneous mixture of four elements
Answers
Answer:
The correct option is;
3. A homogeneous mixture of two compounds
Explanation:
An homogeneous mixture is one where the components of the mixture are evenly dispersed such that the individual components cannot be seen to be isolated and distinguishable and having a constant composition of the constituents
The image displays three atoms (red circle, cyan triangle, and orange rectangle). The red circle appear to be bonded in pairs while the cyan triangles are bonded to the orange rectangles making a total of two compounds
The arrangement of the compounds in the mixture appear to be very evenly distributed to suggest an homogeneous mixture
The visibility of the compounds should be for an illustrative purpose.
What evidence demonstrates that chlorine in the stratosphere is primarily from man-made chemicals rather than from natural sources such as volcanoes?
Answers
Answer:
The evidence that demonstrated that the Chlorine in the stratosphere is believed to come primarily from CFCs ( Chlorofluorocarbons) rather than from natural sources such as volcanoes was due to the study conducted in which the amount of chlorine in the stratosphere over the past 20 years was measured and it was discovered that there was an increase over the years. This also corresponded with a rise in CFCs over the same period which shows that the chlorine in the stratosphere was from man made chemicals such as chlorofluorocarbons.
Chlorine in the stratosphere is primarily from man-made chemicals rather than from natural sources such as volcanoes is evident as follows;
Discussion;
Most of the chlorine in the stratosphere is there as a result of human activities, as the figure below illustrates.
Many compounds containing chlorine are released at the ground.
Volcanoes can emit large quantities of hydrogen chloride, but this gas is rapidly converted to hydrochloric acid, which dissolves in rain water, ice, and snow and does not reach the stratosphere.
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clearly distinguish between science and technology
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Answer:
The words science and technology can and often are used interchangeably. But the goal of science is the pursuit of knowledge for its own sake while the goal of technology is to create products that solve problems and improve human life. Simply put, technology is the practical application of science.
Explanation:
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Determinación de pH Expresa las siguientes concentraciones de [H+ ] en función del pH • [H+] = 0.001 M • [H+] = 0.002 M • [H+] = 2.45X10-4 M • [H+] = 5.2X10-9 M • [H+] = 0.04 M
Answers
Answer:
• pH = 3.0
• pH = 2.70
• pH = 3.61
• pH = 8.28
• pH = 1.40
Explanation:
El pH es una medida en química usada para determinar el grado de acidez o basicidad en una solución.
Se define como:
pH = -log₁₀ [H⁺]
El - logaritmo de la concentración molar de H⁺
Para las concentraciones de H⁺ dadas:
• [H+] = 0.001 M
pH = -log (0.001M) = 3
pH = 3.0
• [H+] = 0.002 M
pH = -log (0.002M)
pH = 2.70
• [H+] = 2.45X10-4 M
pH = -log (2.45X10-4 M )
pH = 3.61
• [H+] = 5.2X10-9 M
pH = -log (5.2X10-9 M)
pH = 8.28
• [H+] = 0.04 M
pH = -log (0.04M)
pH = 1.40
Identify the difference between natural and artificial dyes.
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Answer:
Natural dyes, although pure from chemicals, are often times more expensive than chemical dyes.
Answer: natural dyes is dye that it is anything that grow on earth that haven't been possessed and artificial dye mean that it is good for something in your body or something else
Explanation:i search it up
What is 9.871 x 10^-3 in standard form? *
Answers
Answer:
0.009871
Explanation:
[tex] 9.871\times 10^{-3} = 0.009871[/tex]
Answer:
.009871
Explanation:
If the temperature of a gas increased from 100K to 200K and the volume of a gas decreased from 20L to 10L, what is the new pressure I’d the original pressure was 100 kPa?
Answers
Answer:
400 kPa
Explanation:
using General Gas Law
[tex] \frac{100 \times 20}{100} = \frac{p \times 10}{200} [/tex]
[tex]p = 400[/tex]
The concept combined gas law is used here to determine the new pressure of the gas. The pressure of the gas obtained is 400 kPa.
What is combined gas law?The equation connecting the volume, pressure and temperature of a gas can be represented mathematically by an equation called the combined gas law. In this equation the temperature should be always in Kelvin.
The combined gas law is also defined as the ideal gas law without Avogadro's law. It is the combination of Boyle's law, Charles's law and Gay-Lussac's law. The equation is given as:
PV/T = k
Here 'P' is the pressure, 'V' is the volume, 'T' is the temperature and 'k' is a constant. The equation for two gases of different volumes and temperature is:
P₁V₁ / T₁ = P₂V₂ / T₂
Then P₂ = P₁V₁T₂ / T₁V₂
Here the new pressure P₂ is:
P₂ = 100 × 20 × 200 / 100 × 10
P₂ = 400 kPa.
Thus the new pressure is 400 kPa.
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Apollo 17 astronauts eugene cernan and harrison schmitt collected the last samples of moon rocks to bring back to earth in 1972 The astronauts took measurements of the moon rocks using three categories not affected by gravity this is because the earth and moon have different forces of gravity which measurement did they not use?
A-Volume
B-Weight
C-Mass
D-Density
Answers
Answer:
The correct answer is B
Explanation:
This question seeks to test the difference between mass and weight.
Mass is a measurement of the amount of matter present in an object. While weight is a measurement of the force of gravity pulling (the mass of) an object. Hence, measuring the weight of the moon rocks in the moon might be a waste since the weight of the object on earth will produce a different value due to the difference in the force of gravity between the earth and the moon.
Answer:
b
Explanation:
You need 100.00 mL of H20 and 5.00 mL of
liquid plant food to make a solution for your
plants. You forgot to bring a measuring cup
out to the greenhouse, but you do have a scale
and know that the density of H2O is 1.00
g/cm", the density of liquid plant food is 1.21
g/cm' and 1 cm° = 1 mL. How much of the
liquid plant food would you use?
Answers
Answer:
6.05 g
Explanation:
Use the density to convert the volume to a weight.
(5.00 mL) × (1.21 g/mL) = 6.05 g liquid plant food
You will need 6.05 g liquid plant food.
What is the PRECAUTION for an Irritant?
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list one difference between blended fibres and regenerating synthetic fibres
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Answer:
blended is better than synthetic fibre. because blended fabrics have quality of synthetic and natural fibres so they are more better than fabrics. For example terrycot. Blended Fibres are considered better than individual synthetic fibres because they show the advantages of 2 or more fibres.
Why does science need to.change its view on ideas overtime?
Answers
Explanation:
A scientific idea is an explanation for how something works, or the truth about some aspect of the world, that was figured out using the scientific process. ... Scientific ideas change over time as the evidence improves. The more experiments they do , and the more data they collect, the better the scientific ideas become.
an atom Y has atomic number 13. It loses three electrons in order to be stable.
i.) What is the proton number and electron number of the atom
a)before it loses electrons
b) after losing electrons
ii.) name the tyoe of ion formed by the atom when it loses three electrons
Show by illustration
Answers
(B) proton number=10 electron =10
An atom Y has atomic number 13, so the no. of electrons and protons in it is 13 and after loses it will form cation and no. of electrons will become 10.
What is atomic number?Atomic number of an atom is equal to the number of electrons or protons present in that atom.
Before loses electronsNumber of protons and electrons in the atom before loses electron is 13, as given atomic number is 13.
After loses 3 electronsNumber of elctrons in the atom is 10 and number of protons is 13, as protons are present in the nucleus.
Name of the ion which is formed by the atom is cation as it bears positive charge on it.So, number of protons is always same i.e. 13 within the atom and no. of electrons after losing 3 electrons is 10.
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Express each of the following in standard form.
3.6 x 101
6.452 x 102
8.77 x 10-1
6.4 x 10-3
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Answer:3.6 x 101 or 8.77 x 10-1
how many nitrogen atoms are in 18.8 g of barium nitride
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18.8gBa(NO3)2 》》》》gN 》》》》 2.016gN
• Calculate relative formula masses from formulae and
from balanced equations?
Answers
Answer:
Explanation:
Simple molecules have very small masses. Instead of writing their actual masses in grams or kilograms, we usually use their relative formula masses. These are calculated using the chemical formula and the relative atomic masses of the elements in it.
Relative formula mass
Relative atomic mass has the symbol Ar. The Ar for an element is a measure of the mass of its atoms compared to the mass of carbon-12 atoms. The greater the Ar value, the more mass an element's atoms have. The periodic table shows the Ar value for each element. For example, the Ar for carbon is 12, and the Ar for magnesium is 24. This means that a magnesium atom has twice the mass of a carbon atom.
Calculating relative formula mass
Relative formula mass is given the symbol Mr. To calculate the Mr for a substance:
work out how many atoms of each element there are in the chemical formula
add together the Ar values for all the atoms of each element present
For example, the formula for carbon dioxide is CO2. It consists of one carbon atom (Ar = 12) and two oxygen atoms (Ar = 16):
Mr of CO2 = 12 + 16 + 16 = 44
It could also be calculated this way:
Mr of CO2 = (1 × 12) + (2 × 16) = 12 + 32 = 44
Ar and Mr values are just numbers. They have no units because they are relative masses.
Relative formula masses of ionic compounds
Ionic compounds such as sodium chloride do not exist as molecules. However, their relative formula masses are calculated in the same way. The formulae used are their empirical formulae.
1. The Tyndall Effect is most useful for distinguishing between: *
a solute and a solvent
O a suspension and a solution
a colloid and a suspension
a colloid and a solution
Answers
Answer:
a colloid and a solution
Explanation:
When solute particles completely dissolve in a solvent, a true solution is formed. The solute particles in this case are so little that they can not be seen with naked eyes. A true solution does not scatter rays of light.
In a false solution, the solute particles are larger than the solute particles in true solutions but are not large enough to be seen with naked eyes. False solutions scatter rays of light. False solutions are also called colloids.
The major difference between a solution and a colloid is that colloids scatter light rays (Tyndall effect) while a true solution does not scatter light rays.
Undulation in sandy material is called
cross-beds
ripple marks
mud cracks
O fossils
Answers
Answer:
ripple marks
Explanation:
Undulation is defined as the to and fro wavelike motion in a fluid or elastic medium.
Undulation in sandy material is called ripple marks because ripple marks are the sediments of rocks that show wavy structure at its surface due to agitation by water and wind.
Hence, the correct answer is "ripple marks".
Difference between atomic number and atomic weight any 2 points
Answers
Answer:
According to the definitions given, atomic mass which is also called atomic weight is the measured total mass of an element's atom. Whereas, atomic number is nothing but the total number of neutrons and protons in the nucleus of an atom....
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Draw a diagram showing the bonding in:
a) Tetrachloromethane [CCI4]
Answers
Answer:
here u go! ................
Answer:
Hope this is ok :))
Explanation:
How many molecules of sodium oxide will be created if 275 grams of sodium reacts with excess oxygen? Given the equation: 4Na + O2 -> 2Na2O
Answers
Answer:
3.60 x 10^24 molecules Na2O
Explanation:
brainliest to whoever gets it the soonest, what SI unit do you use to measure the length of a book, and what tool and unit for the volume of a box?
Answers
The most appropriate SI unit to use for the volume of a book is centimeters cubed
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Answer:
The SI unit of volume is the cubic meter (m 3 ), which is the volume occupied by a cube that measures 1 m on each side. This very large volume is not very convenient for typical use in a chemistry laboratory. A liter (L) is the volume of a cube that measures 10 cm (1 dm) on each side.
Does the wavelength of light (R.O.Y.G.B.I.V.) affect a plant’s growth?
Answers
Answer:
YES
Explanation:
If we put a plant in a room with an orange light source, then it will grow more efficiently than a plant exposed to other colors.
Yes the wavelength of light (R.O.Y.G.B.I.V.) affect a plant’s growth.
What is wavelength of light ?The wavelength of light can be defined as the distance between the two successive troughs of the light wave, and It is denoted by the Greek letter lambda (λ), simply it can be said as the distance between one crest or trough of one wave and the next wave is known as wavelength.
The Visible Light having wave length ranges from 400 nm to 700 nm and the spectrum of visible light has a number of colors having different wavelengths.
For example, The violet color have the shortest form of wavelength whereas the red color have the longest wavelength, wavelength is inversely proportional to the frequency like longer the wavelength of the light have lower is the frequency.
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the density is 5.4 g/mL and the volume is 12.9 mL.
Answers
Answer:
69.66 g
Explanation:
We have the following from the question;
Density of the substance = 5.4 g/ml
Volume of substance = 12.9 ml
Mass of substance= the unknown
Since we have both density and volume of the substance, the question must be for us to obtain the mass of the substance, hence;
Density= mass/volume
Mass= Density × volume
Mass = 5.4 g/ml × 12.9 ml
Mass= 69.66 g
Which best describes the importance of the microscope to the development of the cell theory?
Answers
Answer:
The answer is "all the cells are too small, which is not seen by the naked eye, that's why we use a microscope to see it".
Explanation:
In the given question the choices were missing so, we define the correct answer only.
Cells are the essential building blocks of all living entities. There will be trillions of cells within the body. They construct a body shape, absorb nutrients, transform them into energy, and conduct specialized features.
It provides stability and guidance, encourages mitotic cell development, encourages active and passive transfer, generates energy, induces metabolic processes, and contraceptive support.
The following water measurements were made: 18 mL of water were measured with a beaker, 128.7 mL of water were measured in a graduated cylinder and 23.45 mL of water were measured in a buret. All of these water samples were then poured together in one container. What total volume of water should be reported, when significant digits are taken into account?
Answers
Answer:
170 mL
Explanation:
The total volume to be reported should be 170 mL.
According to the significant rule in mathematical operations, final answers are usually reported to reflect the accuracy of the least accurate number.
In this case, the least accurate of all the volumes has zero significant digits after the decimal, hence, the final answer after the mathematical operation should also have no significant digits after the decimal.
18 + 128.7 + 23.45 = 170.15
Therefore, the total volume to be reported when significant digits are taken into account would be 170 mL.
which of the following is a scientific question about the cuttlefish?
Answers
Answer:
How does the cuddle fish change its colors?
Please tell me if I'm wrong.
The reactants of a reaction are 2AgClO3 and Na2CO3. According to the law of
conservation of matter, which of the following could be a product?
O A. NaOH
O B. Ag2CO3
O C. CaCO3
O D. AgNO3
Answers
Answer:
The answer is "Option B"
Explanation:
Law:
In the law of the conservation of matter, states the volume of matter throughout the process remains constant. In any particular case, it is closed to the movement of matter. It is mostly on conservation of energy means, that the total mass of the products should consider the sum of the mass, which is the reactant of the event of chemical processes.
Reaction:
[tex]2AgClO_3+ Na_2CO_3= Ag_2CO_3+Na_2ClO_3[/tex]
In the above equation when we react to [tex]2AgClO_3[/tex] from the [tex]Na_2CO_3[/tex], it will give [tex]Ag_2CO_3 \ \ \text{and} \ \ Na_2ClO_3[/tex]. that's why option b is correct.
Answer:
Ag2CO3
Explanation:
What element is depicted by the following electron configuration:
(The electron configuration is in the image)
A. None of these
B. Oxygen
C. Chlorine
D. Sulfur
Answers
Explanation:
Your required answer is sulpher.
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