Different kind of London are used in eyeglasses to help people with eye conditions​

Answers

Answer 1

Answer:

true

Explanation:


Related Questions

Which particles are very far apart from each other are constantly moving and I have no definition shape or volume

Answers

Answer:

Gas particles

Explanation:

Particles in the gaseous state have the greatest amount of energy, they move around rapidly and they have large spaces between them

Chlorine is made up of 75.78% 35cl and 24.22% 37 cl. The atomic mass of 35 CL is 34.969 amu. The atomic mass of 37 CL is 36.966 amu. What is the average atomic mass of a sample of chlorine?

Answers

35.453 amu is the correct answer

a chemist has a jar containing 388.2 g of iron fillings. how many moles of iron does the jar contain?​

Answers

7 mol hope it helpsss

A student is trying to calculate the density of a ball. She already knows the mass, but she needs to determine the volume as well. Which of the following formulas can be used to calculate the volume of the ball?

Group of answer choices

V equals four-thirds times pi times r cubed

V equals one-third times pi times r squared times h

V = s3

V = πr2h

Answers

Answer:

V equals four-thirds times pi times r cubed

Explanation:

Volume = a³ , where a is length of each side. Volume = l × w × h , where l is length, w is width and h is height. Volume = 4/3 πr³ , where r is the radius. Volume = πr²h , where r is the radius and h is the height.

. The center of the atom is called the
(10 Points)
O nucleus
O protons
O electrons
O
neutrons

Answers

Answer:

Protons I think. I might be wrong but I think its Protons

Answer:

the nucleus is the center of atoms and its made of of protons and neutrons

Explanation:

The alkaline earth metals are

Answers

Answer:

Calcium, Magnesium, Barium, strontium, Beryllium, Radium

Explanation:

sorry if im wrong.....:(

The alkaline metals are sodium,Potassium,Lithium,Caesium,
Francium

Which characteristic is expected of a mineral that crystallizes from lava at Earth’s surface?

large crystals
small crystals
magnetic crystals
hexagonal crystals

Answers

Answer:

Small Crystals

Explanation:

Answer:

the answer is B

Explanation:

4) How many grams of carbon dioxide would be needed to produce 3.382 grams of
acetylene (C2H,) using the following reaction?
4 CO2(g) + 2 H20(g) → 2 C2H2(g) +5 02(g)

Answers

Answer:

11.4 g CO₂

Explanation:

Your chemical equation is:

4 CO₂  +  2 H₂O  ⇒  2 C₂H₂  +  5 O₂

You need to produce 3.382 g of acetylene.  To find out how many grams of carbon dioxide you need, first convert grams of acetylene to moles using the molar mass.  The molar mass of acetylene is 26.04 g/mol.

(3.382 g)/(26.04 g/mol) = 0.130 mol C₂H₂

Now, use the mole ratio between acetylene and carbon dioxide to convert from moles of acetylene to moles of carbon dioxide.  You can find the mole ratio by looking at the chemical equation.  The mole ratio is (4 mol CO₂)/(2 mol C₂H₂).

(0.130 mol C₂H₂) × (4 mol CO₂)/(2 mol C₂H₂) = 0.260 mol CO₂

Since you now have moles of carbon dioxide, you can convert to grams using the molar mass.  The molar mass of carbon dioxide is 44.01 g/mol.

0.260 mol × 44.01 g/mol = 11.4 g CO₂

You will need 11.4 g of CO₂ to produce 3.382 g of C₂H₂.

Improvements in which area would help reduce the possibility of damage to the environment when using uranium as a fuel?

A.more-efficient extraction techniques
B.better control of fusion reactions
C.stronger-pumping wells
D.thicker shielding around the reactor

Answers

Answer:

A is the answer; 'more-efficient extraction techniques

Explanation:

I just took the test and got it right :D

Answer:

A is the answer to the question

Which element has a lower ionization energy: F or I?

Answers

Answer:

I just did this question and it’s I

Explanation:

Answer:

Iodine (I) has a lower Ionization Energy.

Explanation:

Our Periodic Trend for Ionization Energy is up and to the right.

We know that Fluorine and Iodine are both in Group 17. However, Fluorine is in Period 2 and Iodine is in Period 5.

According the Coulomb's Law, the greater the distance between the electrons and the nucleus, the less Forces of Attraction (FOA) there are. Since Iodine has a lot more electrons than Fluorine, and those electrons are spread out farther from the nucleus, they will have less FOA acting on them. Therefore, it will require less energy to remove those electrons from Iodine.

Since Iodine has so many electrons, it will also have more core electrons than Fluorine. This will create the Shielding Effect, where the core electrons "shield" the nucleus' FOA. With the reduced FOA, the outer electrons aren't held as closely to the nucleus as the core electrons. Since higher sublevels also means more energy, those outer electrons contain a lot of energy. All electrons want to have the lowest energy level possible, and since the FOA is reduced, less energy is needed to remove the electrons of Iodine rather than Fluorine.

Consider the reaction: CH3COOH(aq)+H2O(l)⇌H3O+(aq)+CH3COO−(aq) K=1.8×10−5 at 25∘C Part A If a solution initially contains 0.265 molL−1 CH3COOH, what is the equilibrium concentration of H3O+ at 25∘C?

Answers

Answer:

[tex][H_3O]^+=2.18x10^{-3}M[/tex]

Explanation:

Hello.

In this case, for the given ionization chemical reaction of acetic, the equilibrium expression is:

[tex]Ka=\frac{[H_3O^+][CH_3COO^-]}{[CH_3COOH]}[/tex]

Since aqueous species are considered only. Next, by introducing the reaction extent [tex]x[/tex] based on the ICE table, in which it equals the concentration of both H3O+ and CH3COO-, we can also write:

[tex]1.8x10^{-5}=\frac{x*x}{0.265M-x}[/tex]

As the acid ionization constant is small in comparison to 0.265 M, we can make an approximation to compute [tex]x[/tex] as shown below:

[tex]1.8x10^{-5}=\frac{x*x}{0.265M}\\\\x=\sqrt{1.8x10^{-5}*0.265}= 2.18x10^{-3}M[/tex]

It means that the concentration of H3O+ is:

[tex][H_3O]^+=2.18x10^{-3}M[/tex]

Best regards.

A solution of acetic acid (Ka  = 1.8 × 10⁻⁵) with an initial concentration of CH₃COOH of 0.265 mol/L has an equilibrium concentration of H₃O⁺ at 25 °C of 2.18 × 10⁻³ M.

Let's consider the reaction for the acid ionization of acetic acid.

CH₃COOH(aq) + H₂O(l) ⇌ H₃O⁺(aq) + CH₃COO⁻(aq)

The acid ionization constant (Ka) is 1.8 × 10⁻⁵ and the initial concentration of the acid (Ca) is 0.265 mol/L.

Considering that it is a weak monoprotic acid, we can calculate the equilibrium concentration of H₃O⁺ at 25 °C using the following expression.

[tex][H_3O^{+} ]= \sqrt{Ka\times Ca } = \sqrt{1.8\times 10^{-5} \times 0.265 } = 2.18 \times 10^{-3} M[/tex]

A solution of acetic acid (Ka  = 1.8 × 10⁻⁵) with an initial concentration of CH₃COOH of 0.265 mol/L has an equilibrium concentration of H₃O⁺ at 25 °C of 2.18 × 10⁻³ M.

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calculate the mass of ethyl chloride to form if 4.66 g of ethylene reacts with an 89.4 percent yield

Answers

Answer:

Explanation:

C₂H₄ + HCl = C₂H₅Cl

28 g                  64.5 g

28 g of ethylene reacts to give 64.5 g of ethyl chloride

4.66 g of ethylene reacts to give 64.5 x 4.66 / 28  g of ethyl chloride

= 10.73g

yield = 89.4 %

ethyl chloride produced = 10.73 x .894

= 9.6 g .

If you squeeze a foam pillow, what kind of energy are you increasing in the foam?

Group of answer choices

Nuclear energy

Sound energy

Chemical energy

Elastic energy

Answers

Answer:

elastic energy

Explanation:

If you squeeze a foam pillow, elastic energy is increasing in the foam. Therefore, option D is correct.

What is elastic energy?

Elastic energy can be described as the mechanical potential energy stored in the physical system as it is subjected to elastic deformation by work performed upon it. Elastic energy takes place when objects are impermanently compressed, stretched, or deformed.

Elasticity theory develops formalisms for the mechanics of solid bodies and materials. The elastic potential energy can be used in mechanical equilibrium. The energy can be described as potential as it will be transformed into other forms of energy.

[tex]{\displaystyle U={\frac {1}{2}}k\,\Delta x^{2}}[/tex]

Forces applied to elastic transfer energy into the material yield energy to its surroundings and can recover its original shape. Materials have limits to the degree of distortion can without breaking or irreversibly altering their internal structure.

The elastic energy of a substance can be defined as the static energy of configuration. It refers to the energy stored by changing the interatomic distances between nuclei.

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Provide the name of the compound composed of two nitrogen atoms and four oxygen atoms,

Answers

ANSWER:

Dinitrogen Tetroxide


If this helped, pls mark brainliest:)

which statement accurately describes the reactants of a reaction?

Answers

Answer:

Option (B) is the correct answer.

Explanation:

Reactants are the species which are present on the left hand side of a chemical equation.

On the other hand, products are the species which are present on the right hand side of a chemical equation.

For example,

Here, NaCl and H_{2}O are the reactants whereas NaOH and HCl are the products.

This also means that products are the new substances which are formed.

Thus, we can conclude that new substances that are present at the end of a reaction accurately describes the products of a reaction.

the one that accurately describes the products of a reaction is : B. new substances that are present at the end of a reaction

For example the process of photosynthesis transform CO2 and other nutrients into O2 and H2O

Answer:

I think its substances that are used up

Explanation:

Please Help -
Complete the table

Answers

Answer:

Proteins

Elements: C, H, O, N, and some S

Monomer: amino acids

Functions: catalyzing chemical reactions, synthesizing and repairing DNA, structural support, transporting materials across the cell

Examples: hemoglobin, actin and myosin, albumin, keratin

Carbohydrates

Elements: C, H, O

Monomer: monosaccharides

Functions: cellular identity, source of energy, storage of energy, structural support, cell signaling, make ATP, convert solar energy

Examples: glucose, starch, glycogen, peptidoglycan, cellulose, chitin

Nucleic Acids

Elements: C, H, O, N, P

Monomer: nucleotides

Functions: storage and expression of genetic information, transmission of genetic code required for making proteins

Examples: DNA, RNA

Lipids

Elements: C, H, O, and some P and N

Monomer: fatty acids

Functions: energy storage, cell structure, insulation and protection, regulating and signaling, digestion

Examples: steroids (cholesterol), waxes, fats and oils, phospholipids

Hope that helps.

You are given a bottle of impure CoSO4 7H2O which is thought to be 74.4% by weight CoSO4 7H2O. You propose to run your own analysis to find out. What weight of sample should you take to get 0.345 g of BaSO4?

Answers

Answer:

[tex]m_{CoSO_4\ \ 7H_2O}^{sample}=0.558gm_{CoSO_4\ \ 7H_2O}[/tex]

Explanation:

Hello.

In this case, considering a representative reaction by which BaSO4 is yielded via CoSO4, for instance:

[tex]CoSO_4\ \ 7H_2O+BaCl_2\rightarrow BaSO_4+CoCl_2+7H_2O[/tex]

Since it is desired to obtain 0.345 g of BaSO4 (molar mass = 233.38 g/mol), we can compute the theoretical mass of CoSO4·7H20 (molar mass = 281 g/mol) via the following stoichiometric procedure:

[tex]m_{CoSO_4\ \ 7H_2O}=0.345gBaSO_4*\frac{1molBaSO_4}{233.38 gBaSO_4}*\frac{1molCoSO_4\ \ 7H_2O}{1molBaSO_4} *\frac{281.00gCoSO_4\ \ 7H_2O}{1molCoSO_4\ \ 7H_2O} \\\\m_{CoSO_4\ \ 7H_2O}=0.415gCoSO_4\ \ 7H_2O[/tex]

Next, given the percent purity of the cobalt (II) sulfate heptahydrate, we can compute the mass of the whole sample as shown below:

[tex]m_{CoSO_4\ \ 7H_2O}^{sample}=0.415gCoSO_4\ \ 7H_2O^{pure}*\frac{100gCoSO_4\ \ 7H_2O^{sample}}{74.4gCoSO_4\ \ 7H_2O^{pure}} \\\\m_{CoSO_4\ \ 7H_2O}^{sample}=0.558gm_{CoSO_4\ \ 7H_2O}[/tex]

Best regards!

To obtain 0.345 g of BaSO₄, we need to weigh 0.559 g of CoSO₄.7H₂O with a purity of 74.4%.

Let's consider a possible reaction for the obtaining of BaSO₄ from CoSO₄.7H₂O.

CoSO₄.7H₂O(aq) + Ba(NO₃)₂(aq) ⇒ BaSO₄(s) + Co(NO₃)₂(aq) + 7 H₂O(l)

We want to find the mass of CoSO₄.7H₂O required to form 0.345 g of BaSO₄. We will consider the following relationships:

The molar mass of BaSO₄ is 233.38 g/mol.The molar ratio of BaSO₄ to CoSO₄.7H₂O is 1:1.The molar mass of 281.10 g/mol.

[tex]0.345gBaSO_4 \times \frac{1molBaSO_4}{233.38gBaSO_4} \times \frac{1molCoSO_4.7H_2O}{1molBaSO_4} \times \frac{281.10gCoSO_4.7H_2O}{1molCoSO_4.7H_2O} =0.416gCoSO_4.7H_2O[/tex]

The purity of the sample is supposed to be 74.4%, that is, there are 74.4 g of CoSO₄.7H₂O every 100 g of sample. The mass of the sample that contains 0.416 g of CoSO₄.7H₂O is:

[tex]0.416gPure \times \frac{100gSample}{74.4gPure} = 0.559gSample[/tex]

To obtain 0.345 g of BaSO₄, we need to weigh 0.559 g of CoSO₄.7H₂O with a purity of 74.4%.

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How does flame spread over liquid depend on the flash point?

Answers

If the liquid is at or above its flash point, the flame spread rate is fast, and the entire pool is engulfed within seconds. ... As the liquid temperature decreases, flame radiation must both heat the liquid to the flash point temperature and supply the heat of vaporization.

Which of the following can be observed without changing the identity of a substance? Select all that
apply.
Flammability
Reactivity
Density
Boiling point

Answers

Density can be observed without changing the identity of a substance

Density can be observed without changing identity of a substance .

What is density?

Density of a substance is defined as the mass of the substance mass per unit of volume. It is represented by a capital letter'D'. It is mathematically defined as   mass divided by volume.

It is defined loosely as weight of substance per unit volume. It is scientifically inaccurate  it is more specifically called as specific weight.Different substances have different densities  and these are related to purity and buoyancy.

Osmium and iridium are the densest known elements. To simplify comparisons, it is replaced sometimes by a quantity which is dimensionless called relative density. Density of a material varies with temperature and pressure. The variation is small for solids and greater for gases. Increase in pressure increases the density.

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What is the mass of Na?
2NaN3
2NaN3 2Na + 3N2
(500g) (?) (3235)

Answers

Answer:

its division

Explanation:

The positively charge subatomic particles that are located in the nucleus are called
(10 Points)
nucleus
protons
electrons
neutrons

Answers

Answer: protons ( positively charged and in the nucleus)

Answer:

Protons

Explanation:

The nucleus contains two type of subatomic particles.

What is the number of moles in .025g (NH4)2Cr2O7?

Answers

Answer:

252.06492

Explanation:

How many grams (NH4)2Cr2O7 in 1 mol? The answer is 252.06492.

We assume you are converting between grams (NH4)2Cr2O7 and mole.

You can view more details on each measurement unit:

molecular weight of (NH4)2Cr2O7 or mol

The SI base unit for amount of substance is the mole.

1 grams (NH4)2Cr2O7 is equal to 0.0039672319337415 mole.

Note that rounding errors may occur, so always check the results.

Use this page to learn how to convert between grams (NH4)2Cr2O7 and mole.

Type in your own numbers in the form to convert the units!

What Types of food molecules make up lettuce

Answers

Atoms and polimoliculs

no one ever helps me ☹️ can y’all look at my questions !?

Answers

Answer:

   [tex]Hope this helps you[/tex] A typical atom consists of three subatomic particles: protons, neutrons, and electrons (as seen in the helium atom below). Other particles exist as well, such as alpha and beta particles (which are discussed below). The Bohr model shows the three basic subatomic particles in a simple manner. Most of an atom's mass is in the nucleus—a small, dense area at the center of every atom, composed of nucleons. Nucleons include protons and neutrons. All the positive charge of an atom is contained in the nucleus, and originates from the protons. Neutrons are neutrally-charged. Electrons, which are negatively-charged, are located outside of the nucleus. [tex]Enjoy your day[/tex]

Explanation:

Answer:

Atoms are the fundamental building blocks of all matter and are composed of protons, neutrons, and electrons. Because atoms are electrically neutral, the number of positively charged protons must be equal to the number of negatively charged electrons. Since neutrons do not affect the charge, the number of neutrons is not dependent on the number of protons and will vary even among atoms of the same element.

Explanation:

hope it helps

Hector went to the grocery store by heading due north at 3 m/s, then turning east and continuing at
the same speed for another three blocks. Which of the following is true about Hector's velocity?
A. Hector's velocity did not change because his direction did not change.
B. Hector's velocity changed because his speed changed.
C. Hector's velocity changed because his direction changed.
D. Hector's velocity did not change because his speed did not change.

Answers

Hector's velocity changed because his direction changed.

Velocity refers to the distance covered per unit time in a specified direction while speed is the distance covered per unit time without taking the direction into account.

We must note that Hector's direction changed. since magnitude and direction are both considered when discussing velocity, then Hector's velocity changed because his direction changed.

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BRANLIEST AND 100 POINTS.

Compare and contrast the structure of yeast and algae.

Answers

Yeast are eukaryotic , single-celled microorganisms classified as members of the fungus kingdom

Algae are photosynthetic organisms that possess photographic pigments such as chlorophyll

Algae is a member of the Protista kingdom, a group of mostly aquatic photosynthetic organisms. Yeast, any one of roughly 1,500 species of single-celled fungi, the majority of which belong to the phylum Ascomycota with just a few Basidiomycota species.

What are characteristics of algae and yeast ?

Algae have a variety of life cycles and range in size from tiny micro species to giant kelps with lengths of up to 60 meters (200 feet).Their cells have characteristics that are unique to animals and plants, and their photosynthetic pigments are more diverse than those of plants. Algae are economically significant as a source of crude oil, a source of food, and a source of a number of pharmaceutical and industrial products for humans. In addition to their ecological roles as oxygen producers and the food base for almost all aquatic life, algae are also important economically. Algae's taxonomy is contentious and subject to rapid revision as new molecular data emerge. A phycologist is someone who studies algae, and the field of study is known as phycology.Yeast, any one of roughly 1,500 species of single-celled fungi, the majority of which belong to the phylum Ascomycota with just a few Basidiomycota species. Yeasts can be found in soils and on plant surfaces all over the world. They are especially common in sugary mediums like fruit nectar and flower nectar. There are hundreds of ascomycete yeast varieties with significant economic value. Select strains of Saccharomyces cerevisiae are the ones that are commonly used to make beer, wine, and bread. Some yeasts, like Candida albicans, Histoplasma, and Blastomyces, can be mild to dangerous to humans and other animals.

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Which type of microscope can be used to view atoms

Answers

Answer:

transmission electron microscope

Explanation:

Answer:

Scanning tunneling microscope

Explanation:

An organic solvent has a density of 1.31 g/mL. What volume is occupied by 57.5 g of the liquid?

mL

Answers

Answer:

The answer is 43.89 mL

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

[tex]volume = \frac{mass}{density} \\[/tex]

From the question

mass = 57.5 g

density = 1.31 g/mL

We have

[tex]volume = \frac{57.5}{1.31} \\ = 43.89312977...[/tex]

We have the final answer as

43.89 mL

Hope this helps you

Drag each tile to the correct location.
Several properties of water are shown. Classify each property as a physical property or a chemical property.
can be split into hydrogen and oxygen
is liquid at room temperature
reacts with certain metals
has a density of 1.0 g/cm3
Physical
Chemical

Answers

Answer:

1) chemical property

2) physical property

3) chemical property

4) physical property

Explanation:

Physical properties:

Physical properties are those properties which can be measured without changing the composition of mater. We can observe the object and tell its physical properties like its texture, physical appearance, color, melting point, boiling point, odor, density etc.

Chemical properties:

Chemical properties involve chemical reaction or we can say that change is happen in mater during chemical reaction and the properties, we measured  during this or as a result of this reaction is called chemical properties. Like flammability, toxicity, combustion, decomposition etc.

1) Water can split into hydrogen and oxygen

chemical property

2) water is liquid at room temperature

physical property

3) water react with certain metals

chemical property

4)The density of water is 1.0 g/cm³

physical property

Answer:

Simplified for PLATO Users : )

A silver chafing dish has a specinc heat capacity of a mass of 1350 How much heat transferred to increase the temperature of by 15.0 degrees * C (For the purpose of of transfer, the dish as the system )

Answers

Answer:

I'm not really sure how to answer it but this is the best I can do:

If the capacity of a mass is 1350 and heat is transferred to increase the temperature by 15. degrees Celcius then the amount of heat that needs to be transferred would be about  45 degrees.

Explanation:

I'm sorry if it's wrong or not exactly the way it's supposed to be answered, I'm not very good with math and temperature problems. But i hope it helps! :)

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