Astronomers send probes to other planets to take pictures of their surfaces. An astronomer thinks that briny water flows on Mars because he noticed certain features in one picture of Mars. Which method did the astronomer
use to form this hypothesis?
1.reading scientific literature
2.making careful observations
3. analyzing a natural experiment
4. conducting a controlled experiment

Answer: 1075.5 mph

Explanation:anything moving at 4.78*10^4 cm/sec

equivalent to

cm —> miles = 1/1.6*10^5

sec —> hr = 1/3600

[4.78*10^4]*3600/1.6*10^5 = 1075.5 mph

Answer:

1. False 2.True3.True? Unsure

Explanation:

Answer:

See explanation below

Explanation:

According to what you state in the problem, we have an ethyne bonded to a cyclopentane.

So, in the 1st step reacts with NaNH₂. In this step, the base which is very strong will substract the hydrogen from carbon 2, forming an anion in there. In the second step, this anion will react with  CH₃I, and form a larger chain, the methyl group is attached to the alkyne.

Finally in the last step reacts with sodium in ammonia, this is to reduct the triple bond to just a single bond and leave an alkane only. The picture below shows these steps.

Hope this helps.

Answer:

55.6 °C

Explanation:

From the question given above, the following data were obtained:

Mass (M) of diamond = 32.0 g

Initial temperature (T₁) = 33.5°C

Heat (Q) required = 360 J

Specific heat capacity (C) of diamond = 0.509 J/gºC

Final temperature (T₂) =?

Next, we shall determine the change in temperature. This can be obtained as follow:

The final temperature can be obtained as follow:

Mass (M) of diamond = 32.0 g

Heat (Q) required = 360 J

Specific heat capacity (C) of diamond = 0.509 J/gºC

Change in temperature (ΔT ) =?

Q = MCΔT

360 = 32 × 0.509 × ΔT

360 = 16.288 × ΔT

Divide both side by 16.288

ΔT = 360 / 16.288

ΔT = 22.1 °C

Finally, we shall determine the final temperature. This can be obtained as follow:

Initial temperature (T₁) = 33.5°C

Change in temperature (ΔT ) = 22.1 °C

Final temperature (T₂) =?

ΔT = T₂ – T₁

22.1 = T₂ – 33.5

Collect like terms

22.1 + 33.5 = T₂

T₂ = 55.6 °C

Therefore, the final temperature is 55.6 °C.

Answer:

More exactly this number is 6.02 x 1023 10 2 3 .

Answer:

Density, d = 5.96 g/mL

Explanation:

Given that,

Mass, m = 105 g

Volume, V = 17.6 mL

We need to find the density of the substance. So,

[tex]d=\dfrac{m}{V}\\\\d=\dfrac{105\ g}{17.6\ mL}\\\\d=5.96\ g/mL[/tex]

So, the density of the substance is 5.96 g/mL.

Answer:

i wish i know

Explanation:

i wish i know

Answer: A: Has little to no reaction; might turn slightly red in color. B: The liquid grows darker in color to a more reddish tone.

Explanation: I didn’t have the necessary materials to complete the experiment so the teacher told me and I put it in my own words.

Answer:

369 ml

Explanation:

Mass of Aluminium (Al) = 20 g

Molar concentration =  2.007M

Molar concentration = Number of moles / Volume

The relationship between mass and number of moles;

Number of moles = Mass / Molar mass

Number of moles = 20 / 27 = 0.741 mol

2.007  = 0.741  / Volume

Volume = 0.741 / 2.007 = 0.369 L

converting to millilitres by multiplying by 1000

Volume = 0.369 * 1000 = 369 ml

Answer:

сфоткай отправь. я не магу зделать

According to the concept of Avogadro's number, there are 29.056×10²³ molecules in 77.2 g of methane.

Avogadro's number is defined as a proportionality factor which relates number of constituent particles with the amount of substance which is present in the sample.

It has a SI unit of reciprocal mole whose numeric value is expressed in reciprocal mole which is a dimensionless number and is called as Avogadro's constant.It relates the volume of a substance with it's average volume occupied by one of it's particles .

According to the definitions, Avogadro's number depend on determined value of mass of one atom of those elements.It bridges the gap between macroscopic and microscopic world by relating amount of substance with number of particles.

Number of atoms can be calculated using Avogadro's number as follows: mass/molar mass×Avogadro's number

In the given example, number of moles=77.2/16=4.825 moles

If 1 mole has 6.023×10²³ molecules , then 4.825 moles will have 4.825×6.023×10²³ /1=29.056×10²³ molecules .

Thus, there are 29.056×10²³ molecules in 77.2 g of methane.

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Answer:

hydrogen

Explanation:

In electrolysis of water, gas evolved at cathode is hydrogen

Answer:

Boiling Water

Explanation:

Boiling water is an example of physical change and not and not a chemical change because the water vapor still has the same molecular structure as liquid water.If the bubbles were caused by the decomposition of a molecule into gas then boiling would be a chemical change.

Answer:

A chemical change results from a chemical reaction, while a physical change is when matter changes forms but not chemical identity. Examples of chemical changes are burning, cooking, rusting, and rotting. Examples of physical changes are boiling, melting, freezing, and shredding

Explanation:

Answer: 3.834

Explanation: 18*0.213

Answer:

1 mole is equal to 1 moles Krypton, or 83.798 grams.

Explanation:

Answer:

any gas takes up 22.4L per mole so 2.4*22.4=53.76

Explanation:

In 2.4 moles at STP, 53.79 litres of N2 gas are present.

Moles are defined as the amount of substance of a system that contain the same number of entities as the number of atoms in 12g of carbon 12.

STP is defined as the standard temperature and pressure. At STP, as system has s temperature of zero degree centigrade or 273 Kelvin and the pressure is 1 atm.

PV= nRT

P= 1 atm

V= ?

n= 2.4 moles

R= 0.0821 L atm /K/mol

1 x V = 2.4 x 0.0821 x 273

V = 53.79 litres

Hence, 53.79 litres of N2 gas is present in 2.4 moles at STP.

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Answer:

90 mV

Explanation:

Faraday constant, F = 96487

Gas constant, R = 8.314

Number of mole of electron transferred, Z = 2

MgCl in solution A, = 0.1 mm

MgCl in solution A, = 100 mm

Using the relation :

E=(RT/ZF) In(Mg out/Mgin)

E = (8.314*298) / (2*96485) * In(100/0.1)

E = (2477.572 / 192970) * 6.9077552

E = 0.0128391 * 6.9077552

E = 0.0886897 V

E = 88.68 mV (approximately 90 mV)

indicator, hope this helps :

Answer:

B

Explanation:

Because that's what is being changed into a different color.

Answer:

Explanation:

4 Li(s) + 1 O2(g) -> 2 Li2O(s)

To calculate the atoms of an element in a given molecule, we need to multiply stoichiometry by the number that is written on the foot of that element. Therefore, the balanced equation is 4 Li(s) + 1 O[tex]_2[/tex](g) [tex]\rightarrow[/tex] 2 Li[tex]_2[/tex]O(s).

Balanced equation is the one in which the total number of atoms of a species on reactant side is equal to the total number of atoms on product side. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, displacement reaction.

The other characteristic of balanced reaction is that physical state should be written with each compound or molecule on reactant and product side. Physical state should be written in brackets. s means solid, l means liquid, g means gas. The balanced equation for the given reaction is 4 Li(s) + 1 O[tex]_2[/tex](g) [tex]\rightarrow[/tex] 2 Li[tex]_2[/tex]O(s)

Therefore, the balanced equation is 4 Li(s) + 1 O[tex]_2[/tex](g) [tex]\rightarrow[/tex] 2 Li[tex]_2[/tex]O(s).

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Answer:

Covalent-network (also called atomic) solids—Made up of atoms connected by covalent bonds; the intermolecular forces are covalent bonds as well. Characterized as being very hard with very high melting points and being poor conductors. Examples of this type of solid are diamond and graphite, and the fullerenes.

I hope it's helpful!

Answer:

network solid

Explanation:

The food has 23629.64 cal

Given

mass = 1000 g of water

temperature increases 23.65 * C

Required

The energy of the food

Solution

Heat absorbed by water :

Q = m . c . Δt

Q = 1000 g x 4.184 J/g°C x 23.65 °C

Q = 98951.6 J

1 Joules = 0.2388 Calories

98951.6 J = 23629.64 cal

Answer:

1. aa

2. They have similar DNA

Explanation:

1. According to the question 1, wrinkled seeds (A) are dominant over round seeds (a) in pea plants. This means that, based on the law of dominance proposed by Mendel, wrinkled seeds will be expressed over round seeds in a heterozygous state (Aa).

However, since the round seed phenotype is a recessive trait, it will only be expressed when the alleles for round seeds (a) are the same in the gene i.e. aa genotype.

2. Based on the information in question 2, Ricky, who is working on a family tree for his school project, realizes that his close relatives all look similar in the pictures he collected. This is possible because of the SIMILARITY OF THEIR DNA (genetic material). Note that, relatives are connected by the genes that are inherited from one another, hence, they possess a similar DNA, which is the most valid reason for the resemblance.

Answer:

[tex]APF(atomic packing factor)=0.31736[/tex]

Explanation:

From the question we are told that

Density of metal [tex]\rho=11.6 g/cm3[/tex]

Atomic weight of [tex]W=157.6 g/mol[/tex]

Atomic radius of [tex]r= 0.127 nm[/tex]

Lattice parameters=>[tex]x=0.523nm[/tex]  and [tex]y=0.330 nm[/tex]

Generally the equation for atomic packing factor is mathematically given as

[tex]APF(atomic packing factor)=\frac{Spere's\ volume}{unit\ cell\ volume}[/tex]

[tex]APF(atomic packing factor)=\frac{N*VN}{VC}[/tex]

Generally the equation for number of atoms N is mathematically given as

[tex]N=\frac{\rho }{atomic raduis*Avacados constant}[/tex]

[tex]N=\frac{11.6 }{0.127*10^{-9}*6.02214086*10^{23} mol-1}[/tex]

[tex]N=4[/tex]

Therefore APF(atomic packing factor)

[tex]APF(atomic packing factor)=\frac{N*VN}{VC}[/tex]

[tex]APF(atomic packing factor)=\frac{4*\frac{4}{3} \pi (0.127)^3}{(0.523)^2 *0.330}[/tex]

[tex]APF(atomic packing factor)=0.31736[/tex]

Answer:

The group number in the periodic table represents number of valence electrons of the elements in a certain group.

Explanation:

There are s, p, d, and f blocks, which you can see in periodic table

The s-block and p-block together are usually considered main-group elements, the d-block corresponds to the transition metals, and the f-block encompasses nearly all of the lanthanides (like lanthanum) and the actinides (like actinium)

There are three main principles, which may useful for you:

Hope this helps!

Answer:

0.292 g/mL.

Explanation:

From the question given above, the following data were obtained:

Mass of object = 28.1 g

Volume of object = 96.2 mL

Density of object =..?

Density of an object is simply defined as the mass of the object per unit volume of the object. Mathematically, it can be expressed as:

Density = mass / volume

With the above formula, we can obtain the density of the object as follow:

Mass of object = 28.1 g

Volume of object = 96.2 mL

Density of object =..?

Density = mass / volume

Density = 28.1 / 96.2

Density of object = 0.292 g/mL

Thus the density of the object is 0.292 g/mL

Answer:

68.1% is percent yield of the reaction

Explanation:

The reaction of methane with oxygen is:

CH₄ + 2O₂ → CO₂ + 2H₂O

Where 2 moles of oxygen react per mole of CH₄

Percent yield is:

Actual yield (28.2g CO₂) / Theoretical yield * 100

To solve this question we need to find theoretical yield finding limiting reactant :

Moles CH₄:

15.1g CH₄ * (1mol / 16.04g) = 0.9414 moles

Moles O₂:

81.2g * (1mol / 32g) = 2.54 moles

For a complete reaction of 0.9414 moles of CH₄ are needed:

0.9414 moles CH₄ * (2 mol O₂ / 1mol CH₄) = 1.88 moles of O₂. As there are 2.54 moles, O₂ is in excess and CH₄ is limiting reactant

In theoretical yield, the moles of methane added = Moles of CO₂ produced. That is 0.9414 moles CO₂. In grams = Theoretical yield:

0.9414 moles CO₂ * (44.01g / mol) = 41.43g CO₂

Percent yield: 28.2g CO₂ / 41.43g CO₂ * 100=