I need help ASAP pls

Answer:

0.638 moles in 63.8g of calcium carbonate

Explanation:

Answer:

D. Metallic Solid

Explanation:

A P E X:L E A R N I N G

Time taken for star to reach Earth = 7.5 years

Given

7.5 light years(distance Earth-star)

Required

Time taken

Solution

Speed of light=v = 3 x 10⁸ m/s

1 light years = 9.461 × 10¹⁵ m= distance(d)

So time taken for 1 light years :

time(t) = distance(d) : speed(v)

t = 9.461 × 10¹⁵ m : 3 x 10⁸ m/s

t = 3.154 x 10⁷ s = 1 years

So for 7.5 light years, time taken = 7.5 years

Answer:

bdnsndmzmkrrbby

Explanation:

hfjdkxkx dnamkynskfkfnd

GGCCATAGGTCCCTTTAGCG

I believe this is correct (I used the complementary base)

Answer:

this is because aluminium is a non renewable source of material. the process to mine it is expensive. the process releases greenhouse gases which are harmful to the environment. it takes a long time to extract the aluminium. it is a way to help reduce waste products.

( this answer will only get you about 5 marks you need one more point in your answer. I just couldn't be bothered to think about another one.)

Explanation:

Na represents the neutral element; Sodium. Because of it's atomic number of 11, It has 11 electrons.

Na+ on the other hand represents a cation. The sodium ion has lost an electron, hence the total number of electrons it has = 10.

The K and L shells each have maximum number of electrons they can accommodate. This is given by the formular; 2n^2

K shell = 2 (1)^2 = 2 electrons

L shell = 2 (2)^2 = 8 electrons

Seeing as Na+ has 10 electrons, It completely filled the K and L shells ( 2 + 8 = 10 )

Answer:

a condensation

Explanation:

the water gets to a boiling point it gets so hot to the point where it rises up in the air when it gets cold it goes down basically

Answer:

the answer is boiling, hope it helps

Answer:

Experimental investigation of heat transfer during pool boiling of two nanofluids, i.e., water-Al2O3 and water-Cu has been carried out. Nanoparticles were tested at the concentration of 0.01%, 0.1%, and 1% by weight. The horizontal smooth copper and stainless steel tubes having 10 mm OD and 0.6 mm wall thickness formed test heater. The experiments have been performed to establish the influence of nanofluids concentration as well as tube surface material on heat transfer characteristics at atmospheric pressure. The results indicate that independent of concentration nanoparticle material (Al2O3 and Cu) has almost no influence on heat transfer coefficient while boiling of water-Al2O3 or water-Cu nanofluids on smooth copper tube. It seems that heater material did not affect the boiling heat transfer in 0.1 wt.% water-Cu nanofluid, nevertheless independent of concentration, distinctly higher heat transfer coefficient was recorded for stainless steel tube than for copper tube for the same heat flux density.

Introduction

Recent advances in nanotechnology have allowed development of a new category of liquids termed nanofluids, which was first used by a group in Argonne National Laboratory USA [1] to describe liquid suspensions containing nanoparticles with thermal conductivities, orders of magnitudes higher than the base liquids, and with sizes significantly smaller than 100 nm. The augment of thermal conductivity could provide a basis for an enormous innovation for heat transfer intensification, which is pertinent to a number of industrial sectors including transportation, power generation, micro-manufacturing, chemical and metallurgical industries, as well as heating, cooling, ventilation, and air-conditioning industry. Literature findings regarding pool boiling of nanofluids can be summarized as follows.

Li et al. [2] studied boiling of water-CuO nanofluids of different concentrations (0.05% and 0.2% by weight) on copper plate. They observed deterioration of heat transfer as compared to the base fluid and attributed this fact to the sedimentation of nanoparticles which leads to the changing of radius of cavity, contact angle, and superheat layer thickness.

You et al. [3] reported that independent of the concentration of the nanoparticles (0.001 to 0.05 g/l) nucleate boiling heat transfer coefficients for water-Al2O3 nanofluid while boiling on plate appeared to be the same as for base fluid. They also found that the size of bubbles increased with addition of nanoparticles to water.

Das et al. [4] conducted an investigation on the pool boiling of water-Al2O3 nanofluids on a horizontal tubular heater having a diameter of 20 mm with different surface roughness at atmospheric pressure. It was found that the boiling heat transfer of nanoparticle-suspensions was deteriorated compared to that of pure water. Compared with pure water, surface roughness of the heating surface could also greatly affect the nucleation superheat. The subsidence of nanoparticles was considered as the main reason for the increase of the superheat.

Vassallo et al. [5] carried out an experiment of water-SiO2 nanofluids boiling on a horizontal NiCr wire at atmospheric pressure. No appreciable differences in the boiling heat transfer were found for the heat flux less than the CHF.

Bang and Chang [6] conducted an experimental investigation on the pool boiling of water-Al2O3 nanofluids on a plain plate at atmospheric pressure. The concentration of nanoparticles was

Answer:

The rising global temperature is causing Arctic warming, which may be triggering summer heat waves in some areas of the world. The author wrote the article to show another possible effect of climate change, even though the mechanism behind these heat waves is not completely understood yet.

Explanation:

plato sample answer

Answer:

b.Phosphorus.

d.Nitrogen.

Explanation:

To know the charge of an ion, we need to consider the octet rule: an atom gains, loses or shares electrons to complete their valence shell with 8 electrons.

Which of the following elements would you expect to form an ion with a charge of negative three?

a.Potassium. NO. K has 1 electron in the valence shell so it loses 1 electron to form K⁺.

b.Phosphorus. YES. P has 5 electrons in the valence shell so it gains 3 electrons to form P³⁻.

c.Aluminum. NO. Al has 3 electrons in the valence shell so it loses 3 electrons to form Al³⁺.

d.Nitrogen. YES. N has 5 electrons in the valence shell so it gains 3 electrons to form N³⁻.

Answer:

When the surface water is warm, the storm sucks up heat energy from the water, just like a straw sucks up a liquid. This creates moisture in the air. If wind conditions are right, the storm becomes a hurricane. This heat energy is the fuel for the storm.

Explanation:

I hope this can help you!

Mass of Li₂O= 719.809 g

Given

1,060 g of CO₂

Required

Mass of Li₂O

Solution

Reaction

Possible compound : Li₂O

Li₂O(aq) + CO₂(g) → Li₂CO₃(aq)

mol CO₂(MW=44 g/mol) :

= 1,060 g : 44 g/mol

= 24.09

From the equation, mol ratio of LiO : CO₂ = 1 : 1, so mol Li₂O : 24.09

Mass Of Li₂O(MW=29.88 g/mol) :

= mol x MW

= 24.09 x 29.88

= 719.809 g

Answer: 2.01588

Explanation: 1 mole is equal to 1 moles H2

Mass of KNO₃ : = 40.643 g

Given

28.5 g of K₃PO₄

Required

Mass of KNO₃

Solution

Reaction(Balanced equation) :

2K₃PO₄ + 3 Ca(NO₃)₂ = Ca₃(PO₄)₂ + 6 KNO₃

mol K₃PO₄(MW=212,27 g/mol) :

= mass : MW

= 28.5 : 212,27 g/mol

= 0.134

Mol ratio of K₃PO₄ : KNO₃ = 2 : 6, so mol KNO₃ :

= 6/2 x mol K₃PO₄

= 6/2 x 0.134

= 0.402

Mass of KNO₃ :

= mol x MW KNO₃

= 0.402 x 101,1032 g/mol

= 40.643 g

Answer:

You count the carbons. The way it is written is confusing but If there are ten carbons then its decane. If it’s 11 then its undecane

9 would be nonane

Explanation:

Incomplete question. However, I assumed you are referring to this poster.

Explanation:

Interestingly, we notice that Harriet Tubman made use of figurative language in her words. She used the literary device of personification; in which a thing or condition is spoken as though it was human or living.

By this using such kind of expression that has been used by literate individuals,  it makes it surprising that Tubman is referred to as an illiterate.

For example, she personified "death", and "liberty" as objects she could have, obviously those were beautiful words which we expect only an educative person to say.

Answer:

The variation of sunlight reaching Earth is one cause of ice ages. Over thousands of years, the amount of sunshine reaching Earth changes by quite a lot, particularly in the northern latitudes, the area near and around the North Pole.

Explanation:

I hope this helps.

Answer: "The geological record appears to show that ice ages start when the continents are in positions which block or reduce the flow of warm water from the equator to the poles and thus allow ice sheets to form. The ice sheets increase Earth's reflectivity and thus reduce the absorption of solar radiation."

Explanation:

i searched it up XD

Answer:

The first one.

Explanation:

Answer:

C2H7N

Explanation:

Answer:

Yes

Explanation:

Atoms bond in different ways. One of such is by transferring their valence electrons from one atom to the other.

This type of bonding is known as electrovalent or ionic bonding.

Answer:

A = 2, B = 4 and C = 3

Explanation:

The problem here entails balancing of the chemical equations.

 It is given as;

                            A Al₂O₃   →  B Al   +  C O₂

To balance this reaction expression, we are going to use a mathematical approach.

Conserving Al; 2A = B

                    O:  3A  = 2C

let A = 1, B  = 2 and C = [tex]\frac{3}{2}[/tex]

 Now multiply through by 2;

       A = 2, B = 4 and C = 3

Answer:

Unknown 4

Explanation:

Answer:

P₁  = 2.82 atm

Explanation:

Given data:

Initial volume = 28 L

Initial pressure = ?

Initial temperature = 65 °C (65 +273.15 = 338.15 K)

Final temperature =  35 °C (35 +273.15 = 308.15 K)

Final volume = 36 L

Final pressure = 2.0 atm

Formula:

P₁V₁/T₁ = P₂V₂/T₂  

P₁ = Initial pressure

V₁ = Initial volume

T₁ = Initial temperature

P₂ = Final pressure

V₂ = Final volume

T₂ = Final temperature

Solution:

P₁V₁/T₁ = P₂V₂/T₂

P₁ =  P₂V₂T₁/T₂ V₁  

P₁  = 2.0 atm × 36 L × 338.15 K / 308.15 K × 28 L

P₁  = 24346.8 atm .L. K / 8628.2 K.L

P₁  = 2.82 atm

The original pressure of the gas whose pressure changed to 2 atm is 2.82atm.

HOW TO CALCULATE PRESSURE:

P1V1/T1 = P2V2/T2

Where;

Learn more at: https://brainly.com/question/13154969?referrer=searchResults

Answer:

It is natural energy coming from nature . Natural energy can be made without the help of humans.

Explanation: