What is the atomic number of silicon​

Answer:

B

Explanation:

scientists always look for evidence

Answer:

Yea its B

Explanation: The person above me legit toke the answer out of my mouth

The initial volume of the gas : 6.43 L

Given

Temperature :

T₁=27+273 = 300 K

T₂=77+273 = 350 K

Volume : V₂=7.5 L

Required

The initial volume=V₁

Solution

Charles's Law  

When the gas pressure is kept constant, the gas volume is proportional to the temperature  

[tex]\tt \dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}[/tex]

Input the value :

V₁=(V₂ x T₁)/T₂

V₁=(7.5 L x 300 K)/350 K

V₁ = 6.43 L

Answer:

1.5 moles of sodium chloride are present.

Explanation:

Given data:

Number of moles of sodium chloride = ?

Number of atoms of sodium chloride = 9.07×10²³

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ atoms

9.07×10²³ atoms  × 1 mol / 6.022 × 10²³ atoms

1.5 moles of sodium chloride are present.

Answer:

new Moon.

waxing crescent Moon.

first quarter Moon.

waxing gibbous Moon.

full Moon.

waning gibbous Moon.

last quarter Moon.

waning crescent Moon.

New moon

Explanation:

Your answer is correct

Answer:

67.89

Explanation:it’s right

The percent composition of carbon in  compound of acrylonitrile is 22.646%.

Percent composition  is defined as a convenient way to record concentration of solution.It is a expression which relates mass of element  to mass of compound  as,mass of element/mass of compound×100.

Percent composition helps in elemental analysis of compound which is useful in analysis of ores also.  It helps in making solutions while performing the titrations.  It helps in prediction of chemical formula which can be predicted by mass and molar mass of an element.

The compound acrylonitrile  has a molar mass 53.06 g/mole and that of carbon is 12 g/mole thus, percent composition of carbon in  compound of acrylonitrile is 12/53.06×100=22.646%.

Thus, the percent composition of carbon in  compound of acrylonitrile is 22.646%.

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Answer: addition and elimination

Explanation:

In addition you add and in elimination you remove (or subtract)

The reactions that are the reverse of one another are addition and elimination. Details about types of reactions are as follows.

A reaction is the transformation in which one or more substances is converted into another by combination or decomposition.

Reactions can be of different types as follows:

However, addition and elimination reactions are reverse of one another because addition involves adding substances while elimination involves removing substances.

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Answer:

carbon dioxide I beleive.

Explanation:

dry ice is frozen liquid carbon dioxide and when it melts it gives off carbon dioxide gas.

Answer:

The children have spent 5 of there years playing and having the time of there lives and the other 5 years are spent losing and gaining brain sells!

hope this helps:)

so sorry if this is wrong!

Answer:

D. the amount of oxygen collected over a period of 12 hours

Explanation:

Photosynthesis is a metabolic reaction performed by the cells of plant. In this reaction, light is used as an energy source to combine carbon dioxide (CO2) and water (H2O) to produce glucose and oxygen gas (O2) as products. In every chemical reaction including photosynthesis, an increase in concentration of reactants will increase the rate of the reaction, which is evident in the amount of products formed.

According to this question where a student is performing an investigation to determine the relationship between a higher than normal concentration of carbon dioxide gas and the rate of photosynthesis. After increasing the concentration of carbon dioxide in water, the student illuminated the plant with a light and collected the bubbles of oxygen gas that were given off from the cut end of the submerged plant.

Based on the above explanation, the best indicator of the rate of photosynthesis in this investigation will be THE AMOUNT OF OXYGEN COLLECTED OVER A PERIOD OF 12 HOURS.

Answer:

Fossil record

Explanation:

but first think about it befor you do so it could be wrong im not a computer

Answer:

5425440 μm

Explanation:

From the question given above,

Length (in ft) = 17.8 ft

Length (in μm) =?

Next, we shall convert 17.8 ft to in. This can be obtained as follow:

1 ft = 12 in

Therefore,

17.8 ft = 17.8 ft × 12 in / 1 ft

17.8 ft = 213.6 in

Next, we shall convert 213.6 in to cm. This can be obtained as follow:

1 in = 2.54 cm

Therefore,

213.6 in = 213.6 in × 2.54 / 1 in

213.6 in = 542.544 cm

Finally, we shall convert 542.544 cm to μm. This can be obtained as follow:

1 cm = 10⁴ μm

Therefore,

542.544 cm = 542.544 cm × 10⁴ μm / 1 cm

542.544 cm = 5425440 μm

Therefore, 17.8 ft is equivalent is equivalent to 5425440 μm

Answer:

C. 414 kJ

Explanation:

Given parameters:

Mass of copper  = 2kg

Unknown:

Amount of energy required to melt the copper  = ?

Solution:

To solve this problem, we use:

       Q  = m L

m is the mass

L is the latent heat of fusion of copper  = 207kJ/kg

So;

        Q = 2 x 207  = 414kJ

Answer:

2

Explanation:

Answer:

The energy transported by a wave is directly proportional to the square of the amplitude. So whatever change occurs in the amplitude, the square of that effect impacts the energy. This means that a doubling of the amplitude results in a quadrupling of the energy.

Answer:

23%

Explanation:

Answer:

3,938.22

Explanation:

(correct me if I'm wrong)

Answer:

See the answer below

Explanation:

Read the following passage and identify the error. During germination, the fertilized egg begins to sprout and grow. Each seed contains an embryo, or tiny plant, and it needs the right condition to grow. These conditions include the basic need of water, the correct temperature, and the right location, which is in the soil. Select the statement that corrects the error in the passage. Seeds are fertilized during germination, not before. Basic conditions include wind, not water. The fertilized egg begins to grow and mature, not an embryo. The fertilized seed begins to grow and sprout, not an egg.

A typical seed consists of a fertilized ovule which forms the embryo. Double fertlization ensures that a structure, the endosperm, surrounds and provide nutrition to the embryo while in a state of inactivity.

During germination, the embryo sprouts and grows given the right conditions of moisture, air, temperature, and other factors that may vary from seeds to seeds.

Answer:

5.95 moles

Explanation:

No of moles = given mass / molar mass

No of moles = 137/23

= 5.95 moles

Answer:

Gravitational potential energy: [tex]GPE_{B}>GPE_{A}>GPE_{C}[/tex]

Kinetic energy: [tex]KE_{B}<KE_{A}<KE_{C}[/tex]

Total mechanical energy: [tex]ME_{A}=ME_{B}=ME_{C}[/tex]

Explanation:

The gravitational potential energy is directly proportional to height ([tex]GPE_{B}>GPE_{A}>GPE_{C}[/tex]). Since there are no non-conservative forces, the total mechanical energy is conserved ([tex]ME_{A}=ME_{B}=ME_{C}[/tex]) and the total mechanical energy is the sum of gravitational potential and kinetic energies. Then:

[tex]GPE_{A} + KE_{A} = GPE_{B} + KE_{B} = GPE_{C} + KE_{C}[/tex] (1)

If we know that [tex]GPE_{B}>GPE_{A}>GPE_{C}[/tex], then we conclude the following inequation for the kinetic energy:

[tex]KE_{B}<KE_{A}<KE_{C}[/tex] (2)

Answer:

Common strong acids include hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid. Common weak acids include acetic acid, boric acid, hydrofluoric acid, oxalic acid, citric acid, and carbonic acid.

Answer:

The answer is D

I searched it up to verify.

Answer: I think the possible answer is B or D

Explanation: There are few of the energies like: Gravitational, electrical, Chemical.....

Answer:

16 g/mol

Explanation:

In CO2, it means we have 1 mole of carbon and 2 moles of oxygen.

However, we want to find the molar mass of just a single mole of oxygen.

Now, from tables of values of elements in electronic configuration, the molar mass of oxygen is usually approximately 16 g/mol.

In essence the molar mass is simply the atomic mass in g/mol

Answer:

Chemical laws are those laws of nature relevant to chemistry. The most fundamental concept in chemistry is the law of conservation of mass, which states that there is no detectable change in the quantity of matter during an ordinary chemical reaction. Modern physics shows that it is actually energy that is conserved, and that energy and mass are related; a concept which becomes important in nuclear chemistry. Conservation of energy leads to the important concepts of equilibrium, thermodynamics, and kinetics.

Explanation:

Have A Wonderful Day !!

Answer:

Chemical laws are those laws of nature relevant to chemistry. ... The laws of stoichiometry, that is, the gravimetric proportions by which chemical elements participate in chemical reactions, elaborate on the law of conservation of mass.

Explanation:

Answer:

rain I think

Explanation:

Precipitation mostly relies on the main source water, that is how snow hail, and other cool weather form are created. So rain I may be wrong.

,

Rain is the most common type of precipitation. Therefore, the correct option is option B among all the given options.

Any liquid and frozen water which condenses in the atmosphere then falls to the ground is referred to as precipitation. Rain, sleet, as well as snow are only a few of its various manifestations. Precipitation is one of three main processes that make up the global water cycle, together with evaporation and condensation.

Water vapor in the clouds condenses into increasing-sized droplets of water, forming precipitation. The drips hit the ground when they are sufficiently hefty. The water droplets can freeze to produce ice if a cloud is colder, as it would be at higher elevations. Rain is the most common type of precipitation.

Therefore, the correct option is option B.

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Explanation:

6.The main pieces of evidence that scientists use to classify organisms are essentially form and evolutionary relationships.

9. chimpanzee

10. The answer is no, lemurs are not bipedal, i.e, they don't use two legs for walking like human do and they don't have language like ours.

Answer:

Elements

Explanation:

An element is any substance that cannot be broken down into simpler form by ordinary chemical means.

Elements are distinct substances that cannot be split up into simpler substances. .

Such substances consist of only one kind of atom. There are over hundred elements known till date. Elements are made up of unique atoms. In a chemical reaction, elements combines and rearranges.

Answer:

Sodium reacts more quickly, generating enough heat to melt itself and to occasionally ignite the hydrogen gas, producing a yellow-orange flame characteristic of sodium. The potassium reacts violently, immediately bursting into a flame which has the characteristic violet color of potassium.

Explanation: