The occurrence of elements properties in which it repeats every after the eight elements named a periodicity.
Periodicity would be the reappearance of identical features in an element's behavior when it is organized in atomic number-increasing at frequent intervals.
The repeating of a comparable electronic configuration of an element's atoms in its outermost electron shell after such a predetermined regular interval that's what causes periodicity in its properties.
The elements were organized by chemist John A. R. Newland in order of increasing their atomic weight. He gave it the name "the principle of Octaves" and described how a particular collection of qualities recurs every eight places.
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Which of the following is a true statement?
Work requires only sound energy.
Energy can accomplish work.
Energy is not necessary to do work.
Work requires only light energy.
Answer:
b) energy can accomplish work
Explanation:
In which of the following cases is the vapor pressure of ethanol greatest?
A. mole fraction of ethanol in water = 0.10
B. mole fraction of ethanol in water = 0.25
C. mole fraction of ethanol in water = 0.50
D. pure ethanol
Answer:
The answer Is c. mole fraction of ethanol in water=0.50
Explanation:
Is an irony on the discrepancy between the expected result and actual result?
Irony of situation is a discrepancy between the expected result and actual results. Irony involves the perception that things are not what they are said to be or what they seem.
What is irony?One thing is expressed while another is meant in an ironic statement. For example, on a chilly, wet gray day, you would exclaim, "What a gorgeous day!" Alternatively, if you were suffering from a severe case of food sickness, you may respond, "Wow, I feel terrific today." "ffers points of view and ideas that are, at most, intriguing... However, it does not reach the truth." Ronagh and Souder are particularly concerned with scientific assertions that are not meant to be taken seriously.
Here,
The irony of the issue is the difference between the expected and actual results. Irony is the impression that things are not what they appear to be or what they are purported to be.
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4. Markeith found several fossils and decided to use Carbon-14,
which has a half-life of 5,730 years, to measure the age. How old is
each rock? Please help
b. A fossil that has 6. 25 % of its carbon atoms still
unstable?
C. A fossil that has 75% of its atoms STABLE?
A fossil that has 6.25% of its carbon atoms is still unstable.
Carbon-14 dating is a method of determining the age of organic material. Measures the amount of carbon-14 (a radioactive isotope of carbon) present in the sample. The half-life of carbon-14 is 5,730 years. This means that after 5,730 years, half of the carbon-14 atoms in the sample have decayed to nitrogen.
If 6.25% of the fossil carbon atoms are unstable, this means that 93.75% of the carbon-14 atoms in the sample have already decayed. To determine the age of a fossil, the following formula can be used:
Age = (half-life x ln(1-(fraction of decayed carbon-14/100))) / ln(2)
Age = ( 5,730 x ln(1 - (93.75/100))) / ln(2)
age = 11,460 years old
c. A fossil in which 75% of the atoms are STABLE.
If 75% of the fossil atoms are STABLE, this means that 25% of the carbon-14 atoms in the sample have decayed. The same formula as above can be used to determine the fossil age. 75 )) / ln(2)
Age = 23,120 years
Please note that these are approximate values, as the actual age of the fossils may be affected by various factors such as contamination, preservation, and measurement error.
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What is the best description of the constructive interference of light?
A.) The crest of one wave overlaps with the crest of another.
B.) A mechanical wave meets an electromagnetic wave.
C.) The crest and trough of two waves intersect.
D.) A longitudinal wave meets a transverse light wave.
Answer: The crest and trough of two waves intersect.
Explanation:
The best description of the constructive interference of light is the crest and trough of two waves intersect.
What is Constructive Interference ?When two waves travel in the same direction and are in phase with each other, their amplitude gets added, and the resultant wave is obtained. Here, the waves are said to have undergone constructive interference.
Constructive interference is a type of interference that occurs at any location along the medium where the two interfering waves have a displacement in the same direction
The best description of the constructive interference of light is the crest and trough of two waves intersect.
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Determine the empirical formula for each
compound.
a.
ethylene (C,H,)
b.
ascorbic acid (CH,O)
C.
naphthalene (CH)
Ethylene C2H2 , ascorbic acid formula C₆H₈O₆, naphthalene Chemical formula C₁₀H₈.
What the empirical formula tells us?The relative ratios of the various atoms in a compound are given by an empirical formula. The ratios are still valid at the molar level. H 2 O is made up of two hydrogen atoms and one oxygen atom. Similar to this, 1.0 mole of H2O is made up of 1.0 mole of oxygen and 2.0 moles of hydrogen.
What are the ascorbic acid ?Originally known as hexuronic acid, ascorbic acid is an organic molecule having the formula C 6H 8O 6. Although impure samples may appear yellowish, it is a white solid. Water readily dissolves it, resulting in moderately acidic solutions. It is a gentle reducer.
There are two enantiomers (mirror-image isomers) of ascorbic acid, generally referred to as "l" (for "levo") and "d." (for "dextro"). The most prevalent isomer is the l one, which is a naturally occurring form of vitamin C (also known as a "vitamer") and is necessary for both humans and many other animals to survive. Scurvy is caused by vitamin C deficiency and used to be a serious condition affecting sailors on lengthy sea trips. Due to its antioxidant qualities, it is utilized as a nutritional supplement and food additive.
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PbO + NaOH →→
complete and balance the following formula
Answer:
Explanation:
Pb(OH)2 + 2NaOH → Pb(OH)2 + 2NaOH
The balanced equation would be PbO + 2NaOH → Pb(OH)2 + Na2O
The reactant PbO is a lead oxide which is an acidic oxide, it reacts with NaOH, a strong base, to form Pb(OH)2, a lead hydroxide, which is a salt of lead, and Na2O which is sodium oxide , a base.
if you start with 5.5 grams of sodium fluoride how many grams of magnesium fluoride will be produced
From 5.5 grammes of sodium fluoride, 4.1 grammes of magnesium fluoride will be created. The inorganic substance MgF2 stands for magnesium fluoride.
It naturally occurs as the rare mineral sellaite and is a white crystalline salt that is transparent over a broad range of wavelengths and has commercial use in optics used in space telescopes. With the formula NaF, sodium fluoride (NaF) is an inorganic substance. It is utilised in minute quantities in toothpaste, metallurgy, and as a flux in addition to fluoridating drinking water. It is a white or colourless substance that easily dissolves in water. Pharmaceutical manufacturers frequently use it as a source of fluoride. Mass in grammes is equal to 0.06548 times 62.301 grammes of MgF2.
= 0.06548 /62.301 = 4.1grams
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PLSS I need all the help I can get
Answer:
1st one
Explanation:
A. If you have a Periodic Table that is NOT color-coded describe where to look on the periodic table to to find elements which have similar chemical properties.
B. Explain why they have similar chemical properties.
C. Name three elements that have those similarities.
(I need a written paragraph please)
Answer:
Explanation:
A. Periodic table is beautifully arranged to place elements with similar chemical properties together. A family or a group is a vertical column in periodic table that has elements with similar property.
B. They all have similar properties because they all have the same number of valence electrons that determine the chemical properties such as reactivity of the element.
C. Lithium, sodium, potassium all fall in group 1 called alkali metals and these elements all share the property of being some of the most reactive elements.
Convert: 9.94 × 10²² molecules NH3 = ___ mol NH3
5.99 x 10⁴⁶
none of these
2.81
6.06
0.165
Answer:
correct answer is 0.165 moles by calculation
Since carbon-14 decays at a steady rate, it is a reliable method to determine the age of rock samples. True False
The aforementioned claim is TRUE; as carbon-14 degrades steadily, it can be used to accurately estimate the age of rock samples.
Comment on carbon-14.The radioactive isotope of carbon 14 (14C) decays at a constant, well-known pace. Scientists can ascertain how long ago an organic substance died by calculating the quantity of 14C present in a sample of the material, such as bone or wood. This process, known as radiocarbon dating, is frequently used in geology and archaeology to date objects that are up to 50,000 years old.
Since carbon-14 decays steadily, it provides a trustworthy way to estimate the age of rock samples.
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Please balance this equation.
Answer:
C2H5OH + 3O2 → 2CO2 + 3H2O
Explanation:
How many grams of magnesium
sulfate (MgSO4) are dissolved in
0. 965 L of a 0. 0575 M solution?
Molar Mass Mg: 24. 30 g/mol
Molar Mass S: 32. 06 g/mol
Molar Mass O: 16. 00 g/mol
Magnesium sulfate, or MgSO₄, weighs 6.68 g, and dissolves about 0. 965 L of the a 0. 0575 M solutions.
For what use in chemistry?A solution is created when a solvent and a solute, two different compounds, are mixed together. When a salt and a solvents is mixed, a solution is created. Commonly, one substance will dissolve in another to create a solution, such as when salt dissolves in water. Nevertheless, a solution can be produced under any state of matter.
Molar mass MgSO₄ = 120.36 g/mol
You have a 0.0575 M solution
That is equal to 6.9207 g/L or 0.0575 mol/L * 120.36 g/mol.
But you want mass in 0.965 L
Mass equals 0.965 L times 6.9207 g/L, or 6.68 g.
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What does the sun shape indicate?
The Sun is a close second in terms of object radii. It would be so spherical if shrunk to the size of a beach ball that the distance between its widest and narrowest diameters would be significantly smaller than the width of a human hair.
What does the sun symbolize?Our world is greatly influenced by the sun, which controls the weather, ocean currents, seasons, and climate as well as enabling plant life through photosynthesis. Life on Earth would not live without the heat and light provided by the sun.
Because they developed and collapsed under the force of their own gravity, the Sun and the majority of other big objects in space, including stars, planets, and large moons, are spherical. When our Solar System first formed, it was a massive, whirling cloud of gas and dust that gradually shrank due to gravity.
Thus, The Sun is a close second in terms of object radii.
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Hydrochloric acid (HCl) is combined with cesium hydroxide (CsOH) in a neutralization reaction. Which ions will combine to form a salt
The ions will combine to form a salt are Cl- and Cs+ when Hydrochloric acid (HCl) is combined with cesium hydroxide (CsOH) in a neutralization reaction.
HCl + CsOH --> CsCl + H2O
Cesium chloride is the salt that results from the neutralization of hydrochloric acid with cesium hydroxide. Because both of the bonds in salt compounds the positively charged cesium ion and the negatively charged chloride ion have electrical charges, they are referred to as ionic bonds. A neutralization reaction occurs when an acid and a base combine to form salt and water in an aqueous solution. A salt is the name for the aqueous cesium chloride that is created during the process.
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how many liters of a 60% acid solution must be mixed with a 15% acid solution to get 360 L of a 50% acid solution
x + (360 - x) = 360 * 0.50
where x is the amount of the 60% acid solution.
Solving for x, we get: x = 360 * 0.50 - 360 x = 180
Therefore, you will need to mix 180 L of the 60% acid solution with 180 L of the 15% acid solution to get 360 L of a 50% acid solution.
What is acid?Acid is a substance that has a pH level of lower than 7.0 and is capable of corroding or dissolving other substances. It is usually found in aqueous solutions and is a highly reactive substance. Examples of acid include sulfuric acid, hydrochloric acid, nitric acid and acetic acid. These are used in a variety of industries such as food production, industrial cleaning and chemical engineering.
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Free nerve endings in the skin detect changes in skin temperature (getting warmer).
stare the classes of elements involved in covalent compounds
Answer:
h2o,H,O are some of the elements
How did the pressure in the left intrapleural cavity change when the valve was opened?
O The pressure in the intrapleural cavity equalized with the atmospheric pressure.
O It went from a positive number to a negative number.
O It went from a positive number to a negative number and the pressure in the intrapleural cavity equalized with the atmospheric pressure.
O It went from a negative number to zero and the pressure in the intrapleural cavity equalized with the atmospheric pressure.
O It went from a negative number to zero.
The pressure in the left intrapleural cavity changes when the valve was opened as : It went from negative number to zero and the pressure in intrapleural cavity equalized with the atmospheric pressure.
What is meant by intrapleural cavity?The pressure inside the pleural cavity is called as intrapleural pressure. It is characterized as negative pressure when the pressure inside the pleural cavity is typically only a little bit lower than the ambient pressure.
The external intercostal muscles and diaphragm contract during inspiration, expanding the thoracic cavity. As a result, the intrapleural pressure decreases, increasing the transpulmonary pressure and expanding the lungs.
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Calculate each of the following quantities:
A. Volume (ml) of 2.25 M potassium hydroxide that contains 15.0 g of solute enter a 3 significant figure number
B. molarity of 250. ml of solution containing 1.25 moles of glucose
C. volume (ml) of 10.00 M copper(II) nitrate that must be diluted with water to prepare 750.0 ml of a 2.500 M solution (enter to 4 significant figures)
D. Are the following instructions for diluting a 10.0 M solution to a 1.00 M solution correct: "Take 100.0 mL of the 10.0 M solution and add 900.0 mL water"? enter either true or false
(A) Vol. of solvent is 119.8 ml, (B) Molarity (M) of sol. is 5.00 M, (C) V1 of copper nitrate solution is 187.5 ml, (D) The instruction given is false.
(A). To calculate the volume (ml) of a 2.25 M potassium hydroxide solution that contains 15.0 g of solute, we can use the formula:
The unit of measurement for molarity (M) is moles of solute per liter of solvent.
Rearranging the formula to solve for liters of solvent:
Molecularity = moles of solute / liters of solvent (M)
We know that the molar mass of potassium hydroxide (KOH) is 56.1 g/mol. To find the moles of solute, we can divide the given mass (15.0 g) by the molar mass of KOH:
15.0 g / 56.1 g/mol = 0.2679 moles
Now we can plug this value into the formula above:
Liters of solvent = 0.2679 moles / 2.25 M
Liters of solvent = 0.1198 L or 119.8 ml (rounded to 3 significant figures)
(B). To calculate the molarity of a solution containing 1.25 moles of glucose in 250. ml of solvent, we can use the formula:
The unit of measurement for molarity (M) is moles of solute per liter of solvent.
Plugging in the given values:
Molarity (M) = 1.25 moles / 0.250 L
Molarity (M) = 5.00 M
(C). To calculate the volume of a 10.00 M copper(II) nitrate solution that must be added to water to prepare 750.0 ml of a 2.500 M solution, we can use the formula:
M1V1 = M2V2
Where M1 and V1 are the concentration and volume of the original solution, and M2 and V2 are the concentration and volume of the final solution.
We know that the final solution has a volume of 750.0 ml and a concentration of 2.500 M, so we can plug in these values for V2 and M2:
M1V1 = 2.500 M x 750.0 ml
Now we can solve for V1 (the original volume) by rearranging the formula:
V1 = M2V2 / M1
V1 = (2.500 M x 750.0 ml) / 10.00 M
V1 = 187.5 ml (rounded to 4 significant figures)
(D). The instructions "Take 100.0 mL of the 10.0 M solution and add 900.0 mL water" are not correct for diluting a 10.0 M solution to a 1.00 M solution.
To achieve this dilution, you would need to take a smaller volume of the 10.0 M solution and add a larger volume of water, because the final volume should be larger than the starting volume.
For example, you could take 10.0 mL of the 10.0 M solution and add 90.0 mL of water, which would give you a final volume of 100.0 mL and a concentration of 1.00 M. The instruction given above is false.
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Shriram saw the Sun on his LEFT while Kabir saw it on his RIGHT.Based on this, Which of the following statements is true?
Answer:
they were facing the oppisite ways
Explanation:
how was potassium discovered?
Answer:
Potassium was the first metal to be isolated by electrolysis. It was discovered by the English chemist Sir Humphry Davy by decomposing molten potassium hydroxide (KOH) with a voltaic battery.
Explanation:
Potassium was discovered by the English chemist Sir Humphrey Davy.
Please help. I’ll give brainliest.
Answer:
the third one is the one that you should pick
Which two things affect how a lens refracts light?
Answer:
Explanation:
the correct answer is A
Answer:
hey hope this work
The amount of bending depends on two things: Change in speed – if a substance causes the light to speed up or slow down more, it will refract (bend) more. Angle of the incident ray – if the light is entering the substance at a greater angle, the amount of refraction will also be more noticeable.
and the answer i think is A
12.7 grams of magnesium chloride is dissolved into water in a flask and set aside for an experiment. The scientist forgets about the solution and the sunlight evaporates it. She needs at least 11 grams of magnesium chloride to continue the experiment. Will she be able to recover enough magnesium chloride from the original flask to continue the experiment
Answer:
Yes, she will be able to recover enough magnesium chloride from the original flask to continue the experiment
Explanation:
The solution prepared by the scientist contains 12.7g of magnesium chloride. The sunlight will evaporate only the water present. When the volume decreases, the magnesium chloride precipitates. When all water evaporates, all the solute, magnesium chloride precipitates totally.
That means she will recover the 12.7g of magnesium chloride.
Answer: Yes, she will be able to recover 12.7g in the flask
Explanation: Founders Educere answer
16. What are the two types of mixtures?
Heterogeneous and homogeneous mixtures are the two types of mixtures.
How to define the heterogeneous and homogeneous mixtures?When compared to homogeneous mixtures, heterogeneous mixtures can be visually divided into individual components. The most prevalent kind of homogeneous mixture is a solution, which can be a solid, liquid, or gas.
Solid, liquid, or gaseous homogeneous mixtures can exist. They are uniform in both appearance and chemical make-up. Water, air, steel, detergent, saltwater mixture, and other substances are examples of homogeneous mixtures. When two or more metals are combined in a specified proportion, an alloy is created.
A combination is said to be heterogeneous if its composition is not constant throughout. Vegetable soup is a complex concoction.
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An 80.0-gram sample of water at 10.00C absorbs 1680 Joules of heat energy. What is the final temperature of the water
108°C is the final temperature of the water after absorption of 1680 Joules of heat energy.
What is temperature?Temperature is a physical quantity used to measure the average kinetic energy of molecules in matter. This is measured with a thermometer or other device that measures the average kinetic energy of the molecules within the substance. The terms Celsius (°C), Fahrenheit (°F), or Kelvin are commonly used to describe temperature (K). Temperature can affect the physical state of matter.
By rearranging the equation gives:
ΔT = q/mc
Plugging in the given values,
ΔT = 1680/ (80.0 g × 4.184 J/g·C)
= 98°C.
Since the initial temperature was 10°C, the final temperature is:
ΔT = T₂ - T₁
98°C = T₂ - 10
T₂ = 108°C
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What us the % composition of oxygen (O) in iron (III) hydroxide, Fe(OH)
3?
Answer:
44.91% of Oxygen in Iron (III) hydroxide
Explanation:
To solve this question we must find the molar mass of Fe(OH)3 and the molar mass of the oxygen in this molecule. Percent composition will be:
Molar mass Oxygen / molar mass Fe(OH)3 * 100
Molar mass Fe(OH)3 and oxygen:
1Fe = 55.845g/mol*1 = 55.845
3O = 16.00g/mol*3 = 48.00 - Molar mass of Oxygen
3H = 1.008g/mol*3 = 3.024
55.845 + 48.00 + 3.024 =
106.869g/mol is molar mass of Fe(OH)3
% Composition of oxygen is:
48.00g/mol / 106.869g/mol * 100 =
44.91% of Oxygen in Iron (III) hydroxide5. Extend your thinking: What strategies did you use to hunt for moths?
Answer:
Moths are hunted and killed in a variety of ways. I'll explain how we go about hunting and killing moths.
Explanation:
Step-by-Step:
Obtain a sticky trap in the morning and afternoon. It's available at Target and Walmart. Cover it in moth pheromones or anything else you know will attract moths. They will be stuck in the sticky trap for a long time and will eventually die as a result of not being able to escape.
At night, get or buy a lamp and turn it on. This will attract a lot of moths and make them easier to see. Then spray the area with insecticide or insect repellent. Finally, they should perish.
Tip: If a large swarm of moths becomes too much for you to handle, call pest control and they will get rid of them for you!
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