1. Pure Substances can be broken down by physical changes.

True
False

Answer:

Rock

Explanation:

Answer:

the atomic mass of an element is the average mass of the atoms of an element measured in atomic mass unit (amu, also known as daltons, D). The atomic mass is a weighted average of all of the isotopes of that element, in which the mass of each isotope is multiplied by the abundance of that particular isotope

Explanation:

Average atomic mass = f1M1 + f2M2 + … + fnMn where f is the fraction representing the natural abundance of the isotope and M is the mass number (weight) of the isotope. The average atomic mass of an element can be found on the periodic table, typically under the elemental symbol.

Answer:

he atomic mass of an element is the average mass of the atoms of an element measured in atomic mass unit (amu, also known as daltons, D). The atomic mass is a weighted average of all of the isotopes of that element, in which the mass of each isotope is multiplied by the abundance of that particular isotope.

The energy of a wave : 8.835.10⁻¹⁷ J

The energy in one photon can be formulated as

Where

h = Planck's constant (6.626.10⁻³⁴ Js)

f = Frequency of electromagnetic waves

f = c / λ

c = speed of light

= 3,10⁸  m/s

λ = wavelength

λ = wavelength  of a wave = 2.25 nm = 2.25 x 10⁻⁹m

[tex]\tt E=h.\dfrac{c}{\lambda}\\\\E=6.626.10^{-34}\times \dfrac{3.10^8}{2.25.10^{-9}}\\\\E=8.835\times 10^{-17}~J[/tex]

Answer:

1)conduction

2) convection

3) conduction

4) radiation

5) radiation

6) radiation

7) conduction

8) conduction

9) radiation

10) convection

Explanation:

not 100% sure

Answer: the answer is 2g because you subtract 32-34 and get 2 and add the get so 2g

Explanation:

2 g of hydrogen reacts with 32 g of oxygen to produce 34 g of hydrogen peroxide.

To determine the amount of hydrogen that reacts with 32 g of oxygen to produce 34 g of hydrogen peroxide ([tex]H_2O_2[/tex]), we need to apply stoichiometry.

First, we find the molar masses:

Molar mass of oxygen ([tex]O_2[/tex]) = 16 g/mol

Molar mass of hydrogen peroxide ([tex]H_2O_2[/tex]) = 34 g/mol (given)

Next, we calculate the number of moles for oxygen and hydrogen peroxide:

Moles of oxygen = mass/molar mass = 32 g / 16 g/mol = 2 moles

Moles of hydrogen peroxide = mass/molar mass = 34 g / 34 g/mol = 1 mole

Since hydrogen peroxide has two hydrogen atoms, it requires twice the moles of hydrogen. Therefore, the moles of hydrogen required are also 2 moles.

Finally, we convert the moles of hydrogen to grams:

Mass of hydrogen = moles × molar mass = 2 moles × 1 g/mol = 2 g

So, 2 g of hydrogen reacts with 32 g of oxygen to produce 34 g of hydrogen peroxide

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Answer:

6 days

Explanation:

The following data were obtained from the question:

Original amount (N₀) = 100 mg

Amount remaining (N) = 6. 25 mg

Time (t) = 24 days

Half life (t½) =?

Next, we shall determine the decay constant. This can be obtained as follow:

Original amount (N₀) = 100 mg

Amount remaining (N) = 6. 25 mg

Time (t) = 24 days

Decay constant (K) =?

Log (N₀/N) = kt / 2.303

Log (100/6.25) = k × 24 / 2.303

Log 16 = k × 24 / 2.303

1.2041 = k × 24 / 2.303

Cross multiply

k × 24 = 1.2041 × 2.303

Divide both side by 24

K = (1.2041 × 2.303) / 24

K = 0.1155 /day

Finally, we shall determine the half-life of the isotope as follow:

Decay constant (K) = 0.1155 /day

Half life (t½) =?

t½ = 0.693 / K

t½ = 0.693 / 0.1155

t½ = 6 days

Therefore, the half-life of the isotope is 6 days

Answer:

Unlike lactic acid fermentation where-in the end product is lactic acid, the 'waste' material in an alcohol respiration is ethanol (an alcohol) and CO2 (carbon dioxide). Human beings have already perfected the use of this process for commercial purposes like in the production of beer, wine and bread

Explanation:

In alcoholic fermentation, pyruvate changes to alcohol and carbon dioxide. This type of fermentation is carried out by yeasts and some bacteria.

Answer:

option A is the ans i think so

If an unknown solution has pH of 9 the solution is classified as a base as it has larger concentration of hydroxyl ions.

According to the Arrhenius concept, base is defined as a substance which yields hydroxyl ions on dissociation.These ions react with the hydrogen ions of acids to produce salt in an acid-base reaction.

Bases have a pH higher than seven as they yield hydroxyl ions on dissociation.They are soapy in touch and have a bitter taste.According to the Lowry-Bronsted concept, base is defined as a substance which accepts protons .Base react violently with acids to produce salts .Aqueous solutions of bases can be used to conduct electricity .They can also be used as indicators in acid-base titrations.

They are used in the manufacture of soaps,paper, bleaching powder.Calcium hydroxide ,a base is used to clean sulfur dioxide gas while magnesium hydroxide can be used as an antacid to cure acidity.

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Answer:

The substance is phosphorus or D!

Hope this helps!

Answer:

The heavy particles move across the chamber because of the diffusion property of gas particles. The particles move in straight lines and change directions only when they collide with other molecules or the walls of the chamber.

Explanation:

Answer:

Yes. The scientific sources disputed several of the fitness instructor’s points. For example, he mentioned that GMO foods cause food allergies, but two credible sources disputed this claim. The lab technician, however, supported her findings with verifiable scientific information.

Explanation: plato

Answer:

Iconic bonds don't burn easily

Explanation:

Covalent bonds are non metals. Covalent bond (sharing), low temp, low temp, burn easily, poor, polar covalent is good and non-polar covalent is bad.

Ionic - metals and nonmetals, ionic bond is when electrons are gained or lost, high temp, high temp, doesn't burn easily, good, good

Answer:

Explanation:

what do you mean by bond?

Answer:

1. 111.54 kJ

2. 944.68 kJ

3. 339 kJ

4. 94.92 kJ

5. 21.0578 kJ

Explanation:

1. The heat required to melt a given quantity of ice is known as the latent heat of fusion, [tex]L^{\circ}_F[/tex], of ice

[tex]L^{\circ}_F[/tex], of ice = 330 J/g

The heat required to melt a given mass of ice = Mass of ice, m × latent heat of fusion, [tex]L^{\circ}_F[/tex], of ice

The heat required to melt 338 grams of ice = 338 g × 330 J/g = 111,540 J = 111.54 kJ

2. The latent heat of vaporization, l, of water = 2260 J/g

The heat required to convert, m grams of water to steam at

The heat required to convert 418 grams of boiling water into steam = 418 g × 2260 J/g = 944680 J = 944.68 kJ

3. To convert 150 grams of boiling water to steam, we have;

Heat required = 150 g × 2260 J/g = 339,000 J = 339 kJ

4. To convert 42.0 grams of boiling water to steam, we have;

Heat required = 42.0 g × 2260 J/g = 94,920 J = 94.92 kJ

5. The specific heat capacity of steam is 1.996 J/(g·°C)

The heat, Q, required to raise a given mass, m, of steam by Δt °C is given as follows;

Q = m × c × Δt

The heat required to raise the temperature of 422 grams of steam from 110.0 °C to 135.0 °C is therefore;

Q = 422 g × 1.996 J/(g·°C) × (135.0 °C - 110.0 °C) = 21057.8 J

The heat required to raise the temperature of 422 grams of steam from 110.0 °C to 135.0 °C = 21057.8 J = 21.0578 kJ

Answer:

Ajay should pass electric current through the water and connect a bulb to the circuit. If the bulb glows, it means that the water is tap water or else, it is distilled water.

Explanation:

This is because tap water contains little impurities like ions of some salts etc., which help in the conduction of electricity. But, distilled water is pure water and doesn't have any ions present in it. So, it doesn't conduct electricity.

Hope this helped

Ajay can test the distilled water by performing the electricity conduction test.

Distilled water has been the water that has an absence of ions and electrolytes. It has been a poor conductor of electricity.

The tap water has been constituted with minerals, electrolytes, and impurities, which results in the addition of conductivity to the water.

To test whether the water has been distilled or not, the circuit test can be performed The water has dipped wires connected with a battery and a bulb. the distilled water is a poor conductor did not allow the bulb to glow. However, with tap water bulb glow.

Thus, to test the water to be distilled or tap, the electricity conduction test has been performed.

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Answer:

1, 2, 2, 1

Explanation:

This is basically the equation we're trying to balance:

Cu + AgNO₃ → Ag + Cu(NO₃)₂

We start with Copper (Cu): There is 1 atom on the reactants'(left) side and 1 atom on the products'(right) side which means it's balanced

The second is Silver (Ag): There is 1 atom on the reactants' side and 1 atom on the products' side which means it's balanced

The third is Nitrogen (N) and there is 1 atom on the reactants' side and 2 atoms on the products' side. We balance it by multiplying the reactants' side by 2

Cu + 2AgNO₃ → Ag + Cu(NO₃)₂

Silver is now imbalanced so we multiply the silver atoms on the product's side by 2

Cu + 2AgNO₃ → 2Ag + Cu(NO₃)₂

If you count them now, the atoms on each side are the same number

1 Copper atom on each side

2 Silver atoms on each side

2 Nitrogen atoms on each side

6 Oxygen atoms on each side (2 sets of 3 oxygen atoms)

1Cu + 2AgNO₃ → 2Ag + 1Cu(NO₃)₂

Answer:

B Host

Explanation:

this is due to the fact that the organism is hosting the parasite

Answer:

eon,era,period,epoch,and age

Answer: c)winter

HAVE A BLESSED DAY!!!!!

Explanation:

To delineate the the nature of the bonds that would be formed between the two elements, let us first write the electronic configuration of the two species;

  Be  = 2, 2

  F  = 2, 7

 Beryllium is a metal with two valence electrons whereas fluorine is a halogen with seven valence electrons.

When Be loses two electrons it becomes isoelectronic with He;

                 Be →  Be²⁺ + 2e⁻  

Also, when fluorine gains  an electron, it becomes isoelectronic with Ne;

               F  + e⁻ →  F⁻

This loss and gain of electrons between the two elements creates an electrostatic attraction them and they enter into an electrovalent bond.

      Hence;

           Be²⁺  + 2F⁻ → BeF₂

Answer:

How much electricity is uses and any repairs

Explanation:

When purchasing an electrical device, the two financial costs you need to consider are the initial price of the device and the operating costs to make use of the device.

The financial cost is the cost of finance charged per item purchased, it may also include miscellaneous charges associated with the usage of the item.

Here, before you purchase the electrical device, think carefully if:

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Answer:

N have 8 13 neutrons.

Explanation:

Nitrogen-15      Nitrogen-20

     8                             13

Explanation:

Distance is the total length of path one travels.

Displacement is the distance between the initial and final position.

 For example, if your classroom is located 200m from your dormitory, you walk to class and back to your dormitory, your distance is 200m + 200m  = 400m;

  Your displacement is 0m. Your initial and final position is the same so no displacement.

Hey there!

Molar mass SO₂ = 64.066 g/mol

Therefore:

1 mole SO₂ -------------------- 64.066 g

(moles SO₂ ) ??---------------- 5.0 g

( moles SO₂) = 5.0 * 1 / 64.066

(moles SO₂) = 5.0 / 64.066

moles = 0.0780 moles of SO₂

Hope this helps!

Answer:

This question is incomplete

Explanation:

This question is incomplete because of the absence of options. However, Rutherford's model of an atom highlighted the following (which you can use to determine your answer from the missing options)

1) electrons move in fixed circular part (now referred to as electron shells) around a central positively charged nucleus

2) The size of the nucleus is very small relative to the size of the atom

Answer:

their is nothing their btw just letting you know

Answer:

Explanation:

Any substance that contains only one kind of an atom is known as an element. Because atoms cannot be created or destroyed in a chemical reaction, elements such as phosphorus (P4) or sulfur (S8) cannot be broken down into simpler substances by these reactions.

Example: Water decomposes into a mixture of hydrogen and oxygen when an electric current is passed through the liquid. Hydrogen and oxygen, on the other hand, cannot be decomposed into simpler substances. They are therefore the elementary, or simplest, chemical substances - elements.

Each element is represented by a unique symbol. The notation for each element can be found on the periodic table of elements.

The elements can be divided into three categories that have characteristic properties: metals, nonmetals, and semimetals. Most elements are metals, which are found on the left and toward the bottom of the periodic table. A handful of nonmetals are clustered in the upper right corner of the periodic table. The semimetals can be found along the dividing line between the metals and the nonmetals.

Answer:

give him brainlyest my gye

Explanation:

Answer:

The versions of an element with different neutrons have different masses and are called isotopes. The average atomic mass for an element is calculated by summing the masses of the element's isotopes, each multiplied by its natural abundance on Earth.

Explanation: