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Answer:

Elements in the same period have the same (number of electron shells)

Answer:

hi

Explanation:

Explanation:

Antoine Lavoisier is the answer

Answer:

Antoine Lavoisier is the father of chemistry

Explanation:

Antoine-Laurent de Lavoisier, also Antoine Lavoisier after the French Revolution, was a French nobleman and chemist who was central to the 18th-century chemical revolution and who had a large influence on both the history of chemistry and the history of biology.

Answer:

Most reactions occur quickly after ingestion or contact with the allergen, but some can occur up to a few hours later. There can also be a second phase of the reaction when symptoms reoccur. It is important to keep an eye on your child for about 6-8 hours following the first reaction.

Explanation:

When fossil fuels are burnt, CO2 is released into the air and is taken up by plants during photosynthesis to form glucose and subsequently starch.

Fossil fuels contain a large proportion of carbon atoms. When fossil fuels are burnt, these carbon atoms are released as carbon dioxide and escape to the atmosphere as atmospheric CO2 in air.

Recall that plants take up the CO2 in air during the process of photosynthesis. This CO2 becomes combined with water in the presence of sunlight to form glucose.

This glucose is converted to starch and stored in plant tissues. This is how the  carbon atom inside a fossil fuel  becomes a carbon atom inside a plant.

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Answer:

Number of Energy Levels: 4

First Energy Level: 2

Second Energy Level: 8

Third Energy Level: 14

Fourth Energy Level: 2

Explanation:

Hope It Helps!

Answer:

4 energy levels

Explanation:

1st energy level = 2 electrons

2nd energy level = 8 electrons

3rd energy level = 8 electrons

4th energy level = 8 electrons

Answer: 116.12 g/mol

Explanation:

The molecular mass of a formula unit of dimethylglyoxime is calculated as 116 g/mol.

The molecular mass can be given as the sum of the mass of each element in the formula unit of the compound.

The dimethylglyoxime is the compound with molecular formula, [tex]\rm C_4H_8N_2O_2[/tex].

The mass of each element in the compound is:

Substituting the mass in the formula unit of the compound as:

[tex]\rm C_4H_8N_2O_2=4(carbon)+8(hydrogen)+2(nitrogen)+2(oxygen)\\ C_4H_8N_2O_2=4(12)+8(1)+2(14)+2(16)g\\ C_4H_8N_2O_2=116\;g[/tex]

The molecular mass of dimethylglyoxime is 116 g/mol.

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Answer:

Distillation is the process by which sugar can be separated from the sugar solution.

Explanation:

Distillation, or classical distillation, is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation.

Answer:

Boil the water, this would cause the water to evaporate and will leave behind the sugar crystals, which is known as distillation.

Calcium (Ca), strontium (Sr), and barium (Ba) are all located in the same column of the periodic table because they have similar atomic structure and similar chemical properties

From the question, we are to determine why calcium (Ca), strontium (Sr) and barium (Ba) are all located in the same column of the periodic table

The periodic table is a tabular arrangement of chemical elements that is arranged by increasing atomic number and groups elements according to recurring properties.

Elements with similar atomic structure and similar chemical properties appear in the vertical columns. These columns are called groups.

Hence, calcium (Ca), strontium (Sr), and barium (Ba) are all located in the same column of the periodic table because they have similar atomic structure and similar chemical properties

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Answer:

ionic

Explanation:

Iron(II) chloride, also known as ferrous chloride, is the chemical compound of formula FeCl2. It is a paramagnetic solid with a high melting point. The compound is white, but typical samples are often off-white

Answer:

because of the reflection that the Sun makes on the water after it rained.

bởi vì sự phản chiếu mà mặt trời tạo ra trên mặt nước sau khi trời mưa

Explanation:

PbO  +  CO  →  Pb + CO₂

Oxidation States of the Elements

      Reactants     Products

Pb       +2                   0

O       -2, -2               -4

C         +2                 +4

Since the oxidation state/number of Pb decreased, it is being Reduced.

Since the oxidation state/number of C increased, it is being Oxidized.

Answer:

0.225 L = 225 mL

Explanation:

Charles' Law states that for a fixed pressure, the volume is directly proportional to the temperature, which means things expand at the same rate as the rate of it being heated up

Mathematically, we can write that as:

V1/T1 = V2/T2, where 1 and 2 are the two situations

So, when we substitute the values in, we get:

0.25 L/298 K = V2/268 K

Rearranging this, we get:

(0.25/298) x 268 = 0.225 L = 225 mL.

This also makes sense, as the volume reduced a little when the temperature reduced (cooled down)

Let me know if this makes sense, and hope I helped! :)

Answer:

147.28 cm³

Explanation:

Density = m/V

1.29 g = 190 g/cm3/V

V = 190 g/cm³ : 1.29 g

V = 147.28 cm³

The coefficient of oxygen is five which is needed to balance the given chemical equation and equation is C₃H₈ +5 O₂[tex]\rightarrow[/tex] 3 CO₂ +4   H₂O.

Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.

A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .

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Answer:

what do you mean?

Explanation:

Studying the brightness of a star can indeed help scientists determine what part of the life-cycle a star is in. The brightness of a star is directly related to its stage in the life cycle.The statement is true.

During the early stages of a star's life, it is formed from a cloud of gas and dust. As the star contracts under its own gravity, it starts to heat up and emits light. This is known as the protostar stage.

As the star continues to contract, it reaches a point where the core temperature becomes hot enough for nuclear fusion to occur. At this stage, the star enters the main sequence phase, where it will spend the majority of its life. The brightness of the star in this phase is determined by its mass. More massive stars are brighter than less massive ones.

As the star ages, it exhausts its hydrogen fuel in the core and begins to evolve. Depending on its mass, a star can become a red giant, a white dwarf, a neutron star, or even a black hole. Each of these stages has a different brightness profile.

By observing the brightness of a star over time, scientists can gather information about its age, mass, and evolutionary stage. This can provide insights into the star's life cycle and help in understanding the processes occurring within it.

Thus, studying the brightness of a star is an important tool for scientists to determine what part of the life cycle a star is in. By analyzing its brightness profile, scientists can gain valuable information about the star's age, mass, and evolutionary stage.The statement is true.

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Answer:

to create oxygen and energy in the form of sugar

Explanation:

photosynthesis is the process by which plants use sunlight, water, and carbon dioxide

Answer:

p orbital

Explanation:

Answer:

Mantle convection is the very slow creeping motion of Earth's solid silicate mantle caused by convection currents carrying heat from the interior to the planet's surface. The Earth's surface lithosphere rides atop the asthenosphere and the two form the components of the upper mantle.

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Explanation:

The molar mass of a compound can be calculated by finding the molar of the individual atoms that combine to make the compound.

Molar mass of compound =

         ∑ (molar mass of element × number of atoms of the element)

∴ Molar mass of dimethylglyoxime

                 = 4C + 8H + 2N + 2O

                 = [(4 × 12.011) + (8 × 1.0080) + (2 × 14.007) + (2 × 15.999)] g/mol

                 = 116.12 g/mol

Answer:

protons and electrons attract each other.

Explanation:

neutron as no charge,  proton and electron are exactly the same size but opposite. ( the opposite charge attract)

The protons possess a positive charge so they attract negatively charged electrons.

A proton can be described as a stable subatomic particle, a symbol with a positive charge of +1e elementary charge. Proton's mass is slightly less than that of a neutron but 1836 times the mass of an electron.

Protons and neutrons are jointly referred to as "nucleons" each with masses of approximately one atomic mass unit. More than one proton can be present in the nucleus of an atom. They give the attractive electrostatic central force which holds the atomic electrons.

The number of protons in the nucleus is referred to as the atomic number and is represented by the symbol Z. Since each element in the modern periodic table has a unique number of protons, its own unique atomic number, determines the chemical characteristics of the element.

As the neutrons are neutral do not carry any charge so the protons do not attract neutrons.

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Answer

63.55

Explanation:

63

C

u

 has

69.2

%

abundance.

65

C

u

has

30.8

%

abundance.

So, the weighted average is

62.93

×

69.2

%

+

64.93

×

30.8

%

Warm

Explanation:

The warm air is going against the cold

Answer:

Conditions that affect natural selection are reproduction, heredity, variation in fitness or organisms, variation in individual characters among members of the population. If they are met, natural selection automatically results.

The pH range of phenolphthalein is 8.3 - 10.0, which is suitable with the pH range of Strong Acid and Strong base titration and so phenolphthalein is used as a visual indicator in a strong acid-strong base titration.

Any substance that gives a clear visible indication of the presence or absence of a particular concentration of a chemical species, such as an acid or an alkali in a solution, usually by a colour change.

The pH range of Strong Acid and Strong base titration is 3–11 and equivalent point is at 7

the pH range of Strong Acid and Weak base  titration,  is 3–8 and equivalent point is below 7

the pH range of Weak Acid and Strong base  titration, is 6 - 11 and equivalent point is above 7

So for titration , an indicator with suitable pH range is used

The pH range of phenolphthalein is 8.3 - 10.0.

Therefore phenolphthalein is used as a visual indicator in a strong acid-strong base titration.

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