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When the hematite particles rearrange to form a new substance", this statement describes chemical change.

A chemical change is a change of materials into another, new materials with different properties and one or more than one new substances are formed.

As a chemical changes is usually a change where a substance undergoes a chemical change and forms a new substance; which cannot be easily reversed into reactants by any simple physical methods.

In this example the hematite ore forms a new substance by an irreversible chemical change.

Hence, "The hematite particles rearrange to form a new substance", this statement describes chemical change.

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Answer:

the number of electrons in the cell

Complete question is;

Glycerin, C3H8O3, is a nonvolatile liquid. What is the vapor pressure of a solution made by adding 164 g glycerin to 338 mL H2O ​at 39.8°C?

The vapor pressure of pure water at 39.8°C is 54.74 torr and its density is 0.0992 g/cm³

Answer:

28 torr

Explanation:

Let's first find the number of moles of water in 338 mL.

Molar mass of water = 18 g/mole

Formula for number of moles = mass/molar mass.

Mass = density × volume = 0.0992 × 338 = 33.5296 g

Thus;

Number of moles = 33.5296/18 = 1.863 moles.

Let's use the same procedure to find the Number of moles of glycerine.

Molar mass of glycerine from online values = 92.1 g/mol

Thus;

n_glycerine = (mass)/92.1

We have mass and density as 164 g and 0.0992 g/cm³ respectively.

n_glycerine = 164/92.1

n_glycerine = 1.78

Total moles of solution = 1.863 + 1.78 = 3.643 moles

We are told that The vapor pressure of pure water at 39.8°C is 54.74 torr

Thus, since water dominates, then vapour pressure of solution = (1.863/3.643) × 54.74 ≈ 28 torr

Answer:

0, +2

Explanation:

As a pure element, any element or simple compound has an oxidation number of 0. This makes it a lot easier, and can be applied for almost any element or compound that uses one atom, like F2, O3, Zn, Fe, etc. However, in compounds, Zinc's oxidation number tends to be +2, and this is just a rule that I memorized when I learned this topic. Please let me know if you still need help and I hope you understood!

As a pure element, the oxidation number of zinc is zero, but in compounds such as  [tex]ZnCO_3\\[/tex] its oxidation number is +2.

Oxidation number also called oxidation state, is the total number of electrons that an atom either gains or loses in order to form a chemical bond with another atom.

As a pure element, any element or simple compound has an oxidation number of 0. This makes it a lot easier and can be applied for almost any element or compound that uses one atom, like [tex]F_2[/tex], [tex]O_3[/tex], Zn, Fe, etc.

However, in compounds, Zinc's oxidation number tends to be +2.

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Answer:

To determine the number of atoms of Boron that are present within 3.61 grams of Boron Trifluoride, it would be best to convert the grams to moles of the compound and then after that use the Avogadro's number to determine the number of molecules and then use the 1 to 3 ratio to determine the total number of Boron atoms.

Answer: The percentage by volume of alcohol will be 21%.

Explanation:

Given: Volume of solute = 14.7 [tex]cm^{3}[/tex]

Volume of solvent = 70 [tex]cm^{3}[/tex]

Formula used to calculate percentage by volume is as follows.

[tex]Percentage volume = \frac{volume of solute}{volume of solvent} \times 100[/tex]

Substitute the values into above formula as follows.

[tex]Percentage volume = \frac{volume of solute}{volume of solvent} \times 100\\= \frac{14.7 cm^{3}}{70 cm^{3}} \times 100\\= 21 percent[/tex]

Thus, we can conclude that the percentage by volume of alcohol will be 21%.

Answer:

+3·F

Explanation:

The number of objects in the given system = 2 objects

The charge on each object are; q₁ = -Q, q₂ = -Q

The force acting between the objects = +F

The distance between the objects = 2·d

The formula for the force acting between two charged particles is given as follows;

[tex]F=K \times \dfrac{q_{1} \times q_{2}}{r^{2}}[/tex]

Therefore, we get;

[tex]F=K \times \dfrac{-Q \times -Q}{(2\cdot d)^{2}} = K \times \dfrac{Q^2}{4 \cdot d^2}[/tex]

By tripling the charge, q₁, on the first object, we get;

q₂ = 3 × (-Q)

[tex]F_2=K \times \dfrac{-3 \cdot Q \times -Q}{(2\cdot d)^{2}} = K \times \dfrac{3 \cdot Q^2}{4 \cdot d^2} = 3 \times +F = +3\cdot F[/tex]

Therefore, the new force between them, F₂ = +3·F

Answer:

Weight = mass × gravitational

Weight = 60 kg × 9.8 ms²

= 588 N

Explanation:

hope it helps

Weight of the boy = Mass of the boy × g

= 60 × 9.8

= 588kgm/s²

= 588N

Answer:

8.87 × 10³ moles.

Explanation:

To convert number of molecules of sulfur hexafluoride (SF6) to moles (n), we divide by Avogadro's number (6.02 × 10²³)

That is; n = N ÷ nA

According to the question, 5.34 x 10^27 molecules of SF6 was given in this question. Hence, the number of moles it contains is given as:

n = 5.34 x 10^27 ÷ 6.02 × 10²³

n = 5.34/6.02 × 10^ (27-23)

n = 0.887 × 10⁴

n = 8.87 × 10³ moles.

Answer:

-Reversal of the resting potential due to influx of sodium ions

-Mechanism that restores the resting membrane voltage and intracellular ionic concentrations

-Period during which potassium ions are diffusing out of the neuron because of a change in membrane permeability

-A brief reversal of membrane potential that travels along the axon

Explanation:

An action potential is a situation where the membrane potential is briefly reversed from -70mV to +30 mV

There are three steps of the moving action potential, including;

1) The depolarization step, where the membrane resting potential is reversed by the rush of sodium ions into a neuron

2) The repolarization, due to the closing of the voltage-gated sodium channels and the opening of the potassium channels, which is a mechanism that restores the membrane's resting voltage and the ionic concentration in the cell

3) Hyperpolarization, where due to some open potassium channels, there is an increased potassium permeability, and excessive efflux of potassium ions take place, which results in a dip in the membrane potential

4) The above three phases describe the phase of the action potential which is the brief reversal of membrane potential that travels along the axon

Answer:

8,3, 7,7

Explanation:

Answer:

a

Explanation:

I'm not completely sure tho veary sorry if it's wrong

Answer:

the answer is C

Explanation:

as the yeast feeds on sugar and yields the ATP per glucose molecule and Carbon dioxide

19. place moth balls in the closet and observe after several days.

20. whenever wax or a candle burns it turns from solid to liquid but again at room temperature it turns to solid

21. evaporation, condensation, precipitation

22. it produces new substances

23. vinegar Bubbles when baking soda is added

24. steam

The international system of units is known as SI and is a metric system. Mostly used as a system of measurement. It is used in science, technology, and nearly in every part of the country. The system includes coherent units known as derived units.

Hence the option B is correct.

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Answer:

12 mL

Explanation:

Según la pregunta;

V / V% concentración del fármaco = 12%

volumen de la solución = 100 ml

De;

V / V% = volumen de fármaco / volumen de solución

volumen de fármaco = V / V% × volumen de solución

volumen de fármaco = 12/100 × 100

= 12 mL

Answer:

1. Na2CO3 + 2HCl --> 2NaCl + CO2 + H2O

2. 2NaOH + H2SO4 --> Na2SO4 + H2O

3. CaCO3 + 2HCl --> CaCl2 + CO2 + H2O

4. 4Na + O2 --> 2Na2O

Explanation:

this is the reason why aluminium's boiling point is higher than that of sodium. sodium forms Na+ ions, therefore 1 electron is lost from each sodium atom, whereas aluminium forms Al3+ ions, so 3 electrons are lost for each Aluminum atom. The number of delocalised electrons therefore increases from sodium to aluminium, and charge density of the ions increases as the ionic charge increases and size decreases.

Answer:

1) The percentage of oxygen in dry air is _______

C. 21

2) The composition of the Earth’s earliest atmosphere was different to that of the present atmosphere. Which of these gases was present in large amounts in the Earth’s earliest atmosphere?

B. CARBON DIOXIDE

Hope it helps

have a nice day

Answer: The percentage of oxygen in dry air is .  21

Explanation:  Ammonia gases was present in large amounts  in the easth7s earliest atmosphere

Hope it will help you

Answer:

according to me its c part which is correct

Answer:

In the esterification reaction, an OH from the molecule acid and H from the alcohol form a molecule of water.

Ethanol and butanoic acid forms ethyl butanoate

Answer:

Calculate the volume (in L) occupied by 3.40 g of NH3 at STP. (STP: 0 degree Celsius and 1 atmosphere of pressure).

Explanation:

To get the volume of ammonia gas at STP, calculate the number of moles of [tex]NH_3[/tex] in the given amount.

Number of moles of [tex]NH_3[/tex] gas is:

[tex]number of moles of NH_3 gas&=\frac{given mass of the gas}{its molecular mass} \\ &=\frac{3.40g}{17.0g/mol} \\&=0.2 mol.[/tex]

Since,

1 mol of any gas at STP occupies ------- 22.4 L of volume.

then,

0.2 mol of [tex]NH_3[/tex] occupies how much volume?

[tex]=>0.2 mol x \frac{22.4 L}{ 1.0 mol} \\=4.48 L[/tex]

Hence, the volume occupied by 3.40 g of ammonia at STP is --- 4.48 L.

Answer:

The pyruvate dehydrogenase kinase enzyme activity would increase, resulting in an inhibition of pyruvate dehydrogenase activity. ... An in vitro study shows that isocitrate dehydrogenase is activated in the citrate cycle.

Explanation:

i know the answer is a theory

Answer:

Coriolis Effect

Explanation:

The Coriolis Effect is caused by Earths rotation. We can not only see this affecting how winds move, but also where storms form and the movement of  oceans currents.

Answer:

C thermal

Explanation: