The frequency of the light emitted by hydrogen is equal to 4.57 Hz.
What are frequency and wavelength?The frequency of the wave can be defined as the number of oscillations of a wave per second. The frequency has S.I. units of s⁻¹ or Hertz.
The wavelength can be described as the distance between two adjacent crests on a wave.
The relation between frequency, wavelength, and speed of light (c) can be shown as:
c = νλ
Given, the wavelength of the light emitted by H-atom, ν = 6.56 × 10⁻⁷ m
The speed of light, [tex]c =3 \times 10^8\; m/s[/tex]
The frequency of the light emitted by hydrogen atoms can determine from the above-mentioned relationship:
ν= c/λ = 3 ×10⁸/6.56 × 10⁻⁷ = 4.57 Hz
Therefore, the frequency of the emitted light is equal to 4.57 Hz.
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A science class is going to do an experiment to investigate how water temperature changes the rate at which salt dissolves in water. What tool will be needed to measure the temperature of the water?
Answer:
thermometers
Explanation:
Answer: thermometer
Explanation: trust me ;)
A btu is defined as the amount of energy required to raise the temperature of one lb of water by one degree celsius.
a. True
b. False
Answer:One BTU is defined as the amount of energy required to raise the temperature of 1 lb of water through 1 degree Fahrenheit
Explanation:
Would you expect to find calcium metal used in conducting wire or
structural materials? Why or why not?
No, we would not expect to find calcium metal used in conducting wire or structural materials. In its pure metallic form, calcium is unstable and unfit for any structural use.
Why aren't calcium-based electrical lines used?
High temperatures cause calcium to burn in the air, creating nitride and oxide. When it combines with water, hydrogen is produced. Therefore, on Earth, it cannot serve as an electrical conductor.
Is calcium an electrical conductor?
Because metals contain moving electrons, they are effective conductors of electricity. Calcium is a metal. Iodine is a non-metal, and since non-metallic elements lack mobile electrons, they are typically poor conductors or non-conductors of electricity. Consequently, solid iodine does not conduct electricity while solid calcium does. The steel cladding of the silicon-calcium alloy cored wire is covered in silicon calcium powder.
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what quantity is needed to convert between the moles of a given sample of a substance and its mass in grams
The molar mass of the substance is needed to convert between the moles of a given sample of a substance and its mass in grams.
What is molar mass?A compound's molar mass, which is measured in grams per mole, specifies how much of a given material weighs in one mole. In other terms, the molar mass is the sum of the masses of all the atoms that make up a mole of a certain molecule, expressed in grams. As a result, the molar mass is measured in grams/mole.
The compound's molar mass is expressed in grams per mole, or g/mol. The mass of 1 mol, expressed in the SI as g/mol, is the definition of the molar mass. Example: Water has a molar mass of 18.016 g/mol.
Thus, The molar mass of the substance is needed to convert between the moles of a given sample of a substance and its mass in grams.
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The complete question is as follows:
What quantity is needed to convert between the moles of a given sample of a substance and its mass in grams?
a the molar mass of the substance
b the density of the substance
с the physical state of the substance
d all of the above
please help!
Are magnesium and calcium more reactive with oxygen in the air than is aluminum? Support your answer.
Magnesium and calcium are 2nd group elements with 2 valence electrons. They are metals in room temperature and easily lose these electrons to nonmetals such as oxygen.
What is magnesium ?Magnesium is 12th element in periodic table. It is 2nd group element and is a called alkaline earth metals. Its group members are calcium, strontium, and barium.
They contains 2 valence electrons which can be easily lost to a non-metal. Oxygen is highly electronegative element and it contains 6 valence electrons and need two more electrons to achieve octet.
Al is 13th group element it is not as much electropositive as alkaline earth metals. It contains 3 valence electrons and thus it need to lose all these 3 electrons to achieve octet. Hence, Al is less reactive towards O2 in comparison with Mg and Ca.
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Which of the following is an example of a heterogeneous mixture?
salad
milk
paint
toothpaste
Answer:
salad
Explanation:
list at least Three chemical reactions that occur in making bread
Explanation:
Fermentation: When yeast is added to the dough, it begins to ferment the sugars present in the dough, producing carbon dioxide and ethanol. The carbon dioxide helps to leaven the dough, while the ethanol is mostly evaporated during baking.
Maillard reaction: During baking, the heat causes a reaction between the amino acids and sugars in the dough, producing a wide range of compounds that give bread its characteristic flavor and aroma. This reaction is known as the Maillard reaction.
Protein denaturation: The heat of baking causes the proteins in the dough to denature, or lose their native conformation. This helps to give bread its texture and structure, and also contributes to the development of its crust.
a chemist reacted 0.20 moles 4-aminophenol (109.13 g/mol) with 0.25 moles of acetic anhydride (102.09 g/mol) to synthesize acetaminophen. if 22 g acetaminophen (151.163 g/mol) was generated, what was the percent yield of the reaction? (only type the number, not the percent sign)
If 22 g acetaminophen (151.163 g/mol) was generated. The percent yield of the reaction is 72.78 %.
Calculation :
C₆H₇NO + C₄H₆O₃ --> C₃H₉NO₂ + C₂H₄O₂
0.20 moles 0.25 moles 22g
limiting reagrnt --> C₆H₇NO
from reaction equation
.20 mol of acetaminophen = .20*151.163 = 30.23 g
% yield = (practical/ theoritical)yield* 100 = 72.78 %
reaction yield. The reaction yield (absolute yield) of a chemical reaction is the amount of pure, dry product recovered from the reaction. Relative yield or percent yield (%) is commonly calculated to measure the efficiency of chemical reactions in organic synthesis.
Yield, also called reaction yield, is a measure of the molar amount of product to reactant consumed in a chemical reaction, usually expressed as a percentage. Yield is one of the main factors that scientists must consider in organic and inorganic chemical synthesis processes. [2] In chemical reaction engineering, “yield,” “conversion,” and “selectivity” relate to unwanted products, how much of the starting material is consumed (conversion), how much of the desired production A term used to describe the rate at which something is formed (yield). (selectivity) represented as X, Y, and S
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how are components separated using distillation? the substance with the [ select ] vapor pressure is vaporized first, and then it is
The material with the lower boiling point vaporizes first when heated, then condenses and collects.
The heat that is generated during the condensation process of higher boiling vapor is what leads to the process of vaporization. Because it has such a huge surface area, the packing enables vapors to move freely between the ascending and descending directions. In the process of evaporation, the vaporization happens at a temperature lower than the boiling point, whereas in the distillation process, the vaporization happens at the boiling point.
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calculate the mass percent of a nacl solution prepared by mixing 35.0 g nacl with 125.0 ml of pure water.
Mass percent of Sodium Chloride solution prepared by mixing is 21.875%.
A mixture is a chemical substance comprised of two or more unrelated chemical components. A mixture is a physical combination of two or more distinct substances that can take the form of solutions, suspensions, or colloids. Solutions of salt and water are an example of a homogeneous mixture, whereas sand and water and oil and water are instances of heterogeneous mixtures.
Density of Water = 1g/mL
So, 125 mL of water weighs 125g
Mass of [tex]NaCl[/tex] = 35.0g
Total mass of solution = 125g+35g = 160g
Mass % of [tex]NaCl[/tex] =(Mass of [tex]NaCl[/tex] / Total Mass ) × 100
= (35/160) × 100
= 21.875%
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✔ Question 1
Below is a picture of the rock strata of a mountain.
What can you infer about the layers in this picture?
Sedimentary rock layers are referred to as rock strata.
What is a rock?A rock is a dense mass of mineral grains that have grown or been cemented together over time. There are big rocks and little rocks. Pebbles are little rocks.
The sediment grains that are deposited by water, wind, or ice become sedimentary rocks. They are always formed in layers and are referred to as "beds" or "strata," and frequently include fossils.
Weathering, erosion, deposition, compaction, and cementation are the processes that result in the formation of these horizontal layers. Newer layers are deposited and created during this process on top of older layers, allowing for the relative dating of each layer.
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this is the chemical formula for talc (the main ingredient in talcum powder): an analytical chemist has determined by measurements that there are moles of magnesium in a sample of talc. how many moles of oxygen are in the sample? be sure your answer has the correct number of significant digits.
Mg3 (Si,03),(OH), is the chemical formula for talc: an analytical chemist has determined by measurements that there are 90.4 moles of magnesium and 2.43 moles of oxygen in a sample of talc.
Talcum powder is formed from talc. Talc is a mineral created up primarily of metallic element, silicon, and oxygen. As a powder, it absorbs wet well and helps weigh down on friction, creating it helpful for keeping skin dry and serving to forestall rashes.This mineral is employed as a thickening agent and stuff. It's an ingredient in ceramics, paints, and building material.
Talc is a hydrous magnesium sheet salt with the statement Mg3Si4O10(OH)2. The elementary sheet consists of a layer of magnesium-oxygen/hydroxyl octahedra, sandwiched between 2 layers of siliconoxygen tetrahedra.
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compare the temperature changes in the stratosphere with those in the thermosphere. Include the role of ozone in your explanation
The stratosphere, which can be found above the troposphere and below the mesosphere, is the second layer of the Earth's atmosphere (/straetsfr, -to-).
What is stratosphere?The stratosphere is an atmospheric layer that is made up of stratified temperature levels, with the warm layers of air high in the sky and the cool layers of air low in the sky, near the surface of the Earth. The ozone layer's ability to block the sun's ultraviolet (UV) radiation is what causes temperatures to rise with altitude. As opposed to the troposphere, which is close to the Earth's surface, where temperature drops with height, the temperature inversion is a phenomenon.The tropopause border, which separates the temperature inversion from the troposphere, is located between the two layers of the atmosphere.The lower stratosphere can reach heights of 20 km (66,000 ft; 12 mi) close to the equator, 10 km (33,000 ft; 6.2 km) in midlatitudes, and roughly 7 km at the poles (23,000 ft; 4.3 mi). Temperatures range from a mean of 51 °C (60 °F; 220 K) near the tropopause to a mean of 15 °C (5.0 °F; 260 K) towards the mesosphere. The stratosphere's temperatures also alter with the seasons, dropping to especially low levels during the polar night (winter). In the Southern polar vortex, stratospheric winds can reach speeds of up to 60 m/s (220 km/h; 130 mph), significantly exceeding those in the troposphere.To Learn more About stratosphere, refer To:
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what is the number of moles of hydrogen atom in 6.4g of methane CH4
The number of moles of hydrogen atom in 6.4g of methane CH4 is 0.4 moles.
To find the number of moles of hydrogen atoms in 6.4 g of methane (CH4), we need to know the molar mass of methane and use the formula for converting mass to moles:
moles = mass / molar mass
The molar mass of methane is 16.04 g/mol, so we can plug in the values and solve:
moles = (6.4 g) / (16.04 g/mol)
moles = 0.4 moles
There are 0.4 moles of hydrogen atoms in 6.4 g of methane. This is because methane is a compound made up of one carbon atom and four hydrogen atoms, and the number of moles of a compound is equal to the total number of moles of all the atoms in the compound.
Since there are four hydrogen atoms in each mole of methane, there are also 0.4 moles of hydrogen atoms in 0.4 moles of methane.
ANSWER ASAP FOR 90 POINTS Question: Air pressure is...
A.high and low at the bottom
B. same at the top same at the bottom
C.low at the top low at the bottom
D.low at the top hight at the bottom
Air pressure is D.low at the top hight at the bottom.
How much air pressure is typical?Pressure is the force that the air applies to the ground when gravity acts on it. At sea level, there is typically a pressure of 1013.25 millibars, or 14.7 pounds per square inch.
When the air pressure is high, what happens?High pressure frequently heralds sunny, dry weather. Clouds and precipitation are frequently indicative of low pressure. Air that is sinking is related with high pressure. Because it is pushing DOWN on the ground, air pressure is higher.
How do we react to air pressure?High barometric pressure exerts additional pressure against our bodies, which restricts how much tissue can expand. On the other hand, when air pressure is low, our body's tissues can expand more, which results in more pressure.
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A student wants to determine the effect of a fertilizer on the growth of bean plants. She sets
up the following experiment.
Bean
Soil
Fertilizer
Daily water 50 mL
A
Bean
Soil
Daily water 50 mL
2. What does setup "B" represent and why is it important in this experiment?
ANSWER QUESTION 2 NOT QUESTION 1
The experimental set up in B is to observe the growth the green beans without the addition of fertilizer. Thus, we can compare the growth of the plant with and without fertilizer and thereby we can understand the effect the fertilizer on the plant growth.
What is fertilizer?Fertilizers are chemical substances used to nourish the plants by making the soil rich in nutrients and minerals. Plants needs minerals along with water such as potassium, calcium, phosphorous, nitrogen etc.
Sometimes the soil comes deficient of these minerals and we have to fertilize the soli by the addition of the chemicals containing these minerals. Hence, fertilizers provide a nutrient rich soil for plant growth.
The experimental set up with fertilizer added plant and the second one (B) without fertilizer helps to compare the growth in both conditions and we can clearly understand how fertilizers effect the growth of plants by comparing the plant growth in A and B.
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The rate of effusion of substance A is 3 times the rate of effusion of substance B. If the molar mass of substance A is 4.00 g/mol, what is the molar mass of substance B?
The rate of effusion of substance A is 3 times the rate of effusion of substance B, and molar mass of A is 4g/mol, then molar mass of B is 36g/mol.
Graham Law:
The rate of effusion of a gaseous substance is inversely proportional to the square root of its molar mass. This is called Graham's Law
R = k/√M
where k is constant and m is molar mass of the substance.
rate of effusion of substance A is 3 times the rate of effusion of substance B.
molar mass of substance A is 4.00g/mol
Ra = 3Rb
Ra/Rb = √Mb/√Ma
3Rb/Rb = √Mb/√4
3 = √Mb/2
√Mb = 6
Mb = 36
so, molar mass of substance B is 36g/mol.
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how are windbelts formed Please answer ASP its 30 points!!
Answer:due to unequal heating
Explanation:
How many moles of chlorine are present in 3 moles of MgCl2
The amount, in moles, of chlorine that would be present in 3 moles of [tex]MgCl_2[/tex] would be 6 moles.
Stoichiometric problem[tex]MgCl_2[/tex] is made from magnesium and chlorine molecules according to the following equation:
[tex]MgCl_2 --- > Mg^{2+} + 2Cl^-[/tex]
From the above equation, 1 mole of [tex]MgCl_2[/tex] is made up of 1 mole of Mg and 2 moles of Cl.
Following this established ratio, the amount of chlorine that would be present in 3 moles of [tex]MgCl_2[/tex] can be calculated as follows:
1 mole [tex]MgCl_2[/tex] = 2 moles of Cl
3 moles [tex]MgCl_2[/tex] = 2 x 3/1
= 6 moles of Cl
In other words, 6 moles of Cl would be present in 3 moles of [tex]MgCl_2[/tex].
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how many milliliters of 2.50 m hcl (aq) are required to react with 8.05 g of an ore containing 44.0% zn (s) by mass? the molecular weight of zn is 65.38 g/mol.
43.312 mL of 2.50M HCl is required to react with zinc single displacement reaction occurs.
Hydrogen gas and zinc chloride are produced quickly by the reaction of zinc with hydrochloric acid. In a single displacement reaction, zinc metal displaces hydrogen to produce zinc chloride and hydrogen gas. Because the reaction is exothermic, a significant amount of heat is produced.
The reaction goes in following order
[tex]Zn(s)+2HCl(aq)\rightarrow ZnCl_{2}(aq)+H_{2} (g)[/tex]
Percentage of Zn = (mass of Zn/mass of Ore) x 100
Mass of Zn = [tex]\frac{44 \times 8.05}{100}[/tex] = 3.54g
n Zn= [tex]\frac{3.54g}{65.38g}[/tex] per mole = 0.054144
n [tex]HCl[/tex] = 2 x 0.054144 = 0.10828
M= [tex]\frac{n}{V}\times1000[/tex]
V=[tex]\frac{n}{M}\times1000[/tex]
[tex]\frac{0.10828}{2.50}\times1000[/tex] = 43.312 mL
So 43.312 mL of 2.50M HCl is required to react with zinc.
The reaction goes in following order
[tex]Zn(s)+2HCl(aq)\rightarrow ZnCl_{2}(aq)+H_{2} (g)[/tex]
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which metal would you expect to have the highest melting point? which metal would you expect to have the highest melting point? agag tctc rbrb
Among the elements in the periodic table, tungsten metal is expected to have the highest melting point.
Tungsten, having atomic number 74 belongs to the 6th group and 6th period of the periodic table.
It is the metal with the highest melting point i.e 3422°C . For this reason, tungsten is used as a metallic component in the filaments of electric bulbs and in cathode ray tubes.
Tungsten is considered a refractory metal due to its heat-hesistance nature. on the other hand, alkali metals such as Li,Na,K have low melting points because of their large size of atoms and due to which the binding energies of the atoms in the crystal lattice is comparatively low, resulting in low melting point.
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chemical analysis shows that the oxygen-carrying protein hemoglobin is 0.34 percent fe by mass. the actual molar mass of haemoglobin is about 65000g. how many fe atoms are in one molecule of haemoglobin.
Chemical analysis shows that the oxygen-carrying protein hemoglobin is 0.34 percent Fe by mass. the actual molar mass of hemoglobin is about 65000g. There are Fe atoms in one molecule of hemoglobin
Hemoglobin efficiently transports oxygen from the lungs to the body's tissues. Additionally, it helps in the return of carbon dioxide and hydrogen ions to the lungs. For the creation of blood, iron is crucial. Red blood cells and muscle cells contain about 70% of the iron in our bodies. Given the information, we may conclude that:
Mass of Fe in hemoglobin = 0.34% of molar mass of hemoglobin
Mass of Fe in hemoglobin = 0.34% of 65000
= (0.34 x 65000) / 100
= 221 g/mol
We now understand that the molecular weight of iron (Fe) is 55.85 g/mol.
Therefore, the quantity of iron in hemoglobin divided by the molecular mass of iron gives the amount of iron in 1 mole of hemoglobin.
= 221/55.85
= 3.957, which is approximately equal to ‘4’
In line with this, 1 molecule of hemoglobin has 4 Fe atoms in it.
The right response is hence "4".
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how many times acidic is pOH 12 than pOH 10
Answer:
100x less acidic
Explanation:
pOH is the inverse of pH, which is a measure of the acidity or basicity of a solution. The lower the pH of a solution, the more acidic it is, and the higher the pOH, the less acidic it is.
To determine how many times more acidic a solution with a pOH of 12 is compared to a solution with a pOH of 10, we can use the formula:
pH1 / pH2 = 10^(pOH1 - pOH2)
In this case, we are given that the pOH of the first solution is 12 and the pOH of the second solution is 10. We can plug these values into the formula to calculate the ratio of acidity:
pH1 / pH2 = 10^(12 - 10)
= 10^2
= 100
Therefore, a solution with a pOH of 12 is 100 times less acidic than a solution with a pOH of 10.
How many elements belong to the Halogen family? List the member elements by their symbol?
Answer:
5
Explanation:
fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).
For a laboratory exercise in class, a student is given a mixture of small pieces of iron, sand, water, and salt. what physical property could be used to best separate the iron from the other ingredients?
a. Solubility
b. Magnetism
c. Melting Point
d. Electrical Conductivity
Answer:
solubility
Explanation:
the solid substances will be added to water to see which one is soluble
Determine whether each of the examples represents a colligative property or non colligative property
1. freezing point depression
2. density
3. boiling point elevation
4. vapor pressure lowering
5. colour
a. colligative
b. non colligative
c. colligative
d. colligative
e. non colligative
Colligative qualities include boiling point elevation, freezing point depression, and vapor pressure reduction. Color and density are non-colligative qualities.
Colligative qualities are those that rely on the number of particles of solute rather than the composition of the solute.
An example of a colligative property:
Reduced vapor pressure
Boiling point at an elevation
a drop in the freezing point
The osmotic pressure
Non-colligative qualities are those that are determined by the nature of the solute and solvent.
Non-colligative qualities include:
Viscosity
The surface tension
Density
Solubility
As a result, we may deduce that boiling point elevation, freezing point depression, and vapor pressure reduction are all colligative qualities. Color and density are also non-colligative qualities.
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what special equipment did niels bohr use to develop his atomic model?
Neil Bohr used the fluorescent screen and an alpha particle detector to study the structure of an atom.
What is an atom?
An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
The atom as a whole is neutral and stable due to presence of oppositely charged particles.
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a housewife used the aluminum can to keep vinegar. After sometime, it is found that the vinegar is spoiled. Give a reason.
Answer:
Explanation:She was wrong
each of the structures for clocl , ncoh , and clno has atoms connected in the order given in their formulas. identify the type of hybridization for the central atom in each compound.
The type of hybridization for the central atom in each compound is as follows ; Initially we can determine the precise hybridization of each of the mentioned atoms by examining the structures of each molecule.
When we look at ClNO, we can see that the nitrogen atom is linked to chlorine by a single bond while also maintaining a lone pair on oxygen by double bonds. The nitrogen is therefore in a sp2 hybridized form.
As is expected for ClOCl, the molecule has two lone pairs on the oxygen atom and an sp3 hybridized oxygen atom connected to two chlorine atoms.
The carbon atom in NCOH is sp2 hybridized because it is doubly linked to oxygen.
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Khloe is preheating her oven before using it to bake. Khloe wants to predict the final temperature after xx minutes. She wrote the equation y=20x+78y=20x+78, where yy represents the final temperature in degrees fahrenheit. What is the meaning of the yy-value when x=1x=1?.
The final temperature of the oven after being preheated, y is 98 degrees Fahrenheit.
What is the relationship between the final temperature and the time taken to preheat the oven?The relationship between the final temperature, y, and the time taken to preheat the oven, x is given by the equation below:
y = 20x + 78
where;
the final temperature is y,
and the time taken to preheat the oven is x
When x is equal to 1, the value of y can be determined as follows:
y = 20 (1) + 78
y = 98 degrees Fahrenheit.
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