Please do 20 and 21 I will give you extra points!!!

Answer:

but where is yr question????

Answer:

Where is your question bro

Answer:

This atomic model has changed over time. Scientists used the model to make predictions. Sometimes the results of their experiments were a surprise and they did not fit with the existing model. Scientists changed the model so that it could explain the new evidence.

Explanation:

Answer:

Explanation:

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Answer:

seed fibers

Explanation:

since they're harvested separately from their seed

Answer:

A physical change is reversible and the changes made are only physical (smell, physical state, volume, etc) and most importantly no new substance is formed. In a chemical change, a new substance is formed, the chemical properties are changed, and it's permanent.

Answer:

424 grams of sodium are contained in 4moles of na2co3

Crystallization, followed by filtration to remove excess solution, followed by drying on a watch glass or in a warm oven, can yield pure dry crystals of zinc chloride.

Crystallization is defined as the formation of a solid in which the atoms or molecules are highly organized into a structure known as a crystal.

It can also be defined as a natural process that occurs when materials solidify from a liquid or precipitate from a liquid or gas.

There are basically three types of crystallization.

Filtration is defined as the process of removing solid particles from a liquid or gaseous fluid by using a filter medium that allows the fluid to pass through but retains the solid particles.

Zinc oxide that could react with hydrochloric acid to give you the desirable product because acid is a neutralizing base, the reaction of hydrochloric acid with zinc oxide to form zinc chloride and water is a neutralization reaction .

Thus, crystallization, followed by filtration to remove excess solution, followed by drying on a watch glass or in a warm oven, can yield pure dry crystals of zinc chloride.

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Answer:

Explanation:

The liquid nitrogen and oxygen are then separated by fractional distillation . The liquefied air is passed into the bottom of a fractionating column. Just as in the columns used to separate oil fractions , the column is warmer at the bottom than it is at the top.

The sodium ion concentration in the solution of 17.5 mL of 0.1050 M Na₂CO₃ and 46.0 mL of 0.1250 M NaCl is 0.148 M.

To find the Na⁺ concentration in the final solution, we need to find the number of moles of the ion in the Na₂CO₃ and NaCl solutions and the volume of the final solution.  

[tex] C_{Na^{+}} = \frac{n_{t}}{V_{t}} [/tex]  (1)

Where:

[tex] n_{t} [/tex]: is the total number of moles of Na⁺

[tex] V_{t} [/tex]: is the volume of the final solution

The number of moles of Na₂CO₃ can be calculated as follows:

[tex] n_{Na_{2}CO_{3}} = C_{Na_{2}CO_{3}}*V_{Na_{2}CO_{3}} [/tex]

Where:

[tex] C_{Na_{2}CO_{3}} [/tex]: is the concentration = 0.1050 mol/L

[tex] V_{Na_{2}CO_{3}} [/tex]: is the volume = 17.5 mL = 0.0175 L

[tex] n_{Na_{2}CO_{3}} = 0.1050 mol/L*0.0175 L = 1.84 \cdot 10^{-3} \:moles [/tex]

We can find the number of moles of Na⁺ knowing that in 1 mol of Na₂CO₃ we have 2 moles of Na⁺.

[tex] n_{Na^{+}} = \frac{2 \:mol\: Na^{+}}{1\:mol \:Na_{2}CO_{3}}*mol \:Na_{2}CO_{3} = \frac{2 \:mol\: Na^{+}}{1\:mol \:Na_{2}CO_{3}}*1.84 \cdot 10^{-3} \:moles = 3.68 \cdot 10^{-3} \:moles [/tex]

The number of moles of Na⁺ in the NaCl solution is:

[tex] n_{NaCl} = C_{NaCl}*V_{NaCl} = 0.1250 mol/L*0.046 L = 5.75 \cdot 10^{-3} \:moles [/tex]

In 1 mol of NaCl we have 1 mol of Na⁺, so the number of moles of Na⁺ in the NaCl solution is 5.75x10⁻³ moles.

The total number of moles of Na⁺ in the final solution can be calculated as follows

[tex] n_{t} = n_{{Na^{+}}_{Na_{2}CO_{3}}} + n_{{Na^{+}}_{NaCl}} = 3.68 \cdot 10^{-3} \:moles + 5.75 \cdot 10^{-3} \:moles = 9.43 \cdot 10^{-3} moles [/tex]

Hence, the number of moles of Na⁺ in the final solution is 9.43x10⁻³ moles.

The volume of the final solution is given by:

[tex] V_{t} = V_{Na_{2}CO_{3}} + V_{NaCl} = 0.0175 L + 0.046 L = 0.0635 L [/tex]

The concentration of Na⁺ in the final solution is (eq 1):

[tex] C_{Na^{+}} = \frac{n_{t}}{V_{t}} = \frac{9.43 \cdot 10^{-3} moles}{0.0635 L} = 0.148 mol/L [/tex]

Therefore, the concentration of sodium ions in the final solution is 0.148 M.

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I hope it helps you!

Answer:

Step 1 of 3

Here we have to calculate the volume of the solution in mL.

(a) 2.14 g of sodium chloride from a 0.270 M solution

We can calculate the volume of a solution from its molarity. It is known that the molarity of a solution can be calculated as follows,

Molarity = 

Hence volume of solution = 

Here it has been given that,

Mass of NaCl = 2.14 g

Molarity = 0.270 M

Molecular weight of NaCl = 58.44 g/mol

In order to calculate the volume, 1st we have to find out the number of moles,

Number of moles of NaCl = 

                                     =     = 0.03662 mol of NaCl

Now the volume can be calculated as,

volume of solution = 

               =    = 0.136 L or 136 mL solution

Hence the volume of NaCl is found to be 136 mL.

Answer:

CH4+3/2O2⇒CO2+2H2O

mCO2=2.8*44=123.2

Explanation:

Answer:

BONJOUR.

CHEMICAL CHANGE ARE THOSE THAT FORM A NEW SUBSTANCE

PHYSICAL CHANGE ARE THOSE THAT DOESN'T FORM A NEW SUBSTANCE.

OPTION D IS THE ANSWER

I HOPE IT IS HELPFUL.

MERCI

The dew point is the temperature the air needs to be cooled to (at constant pressure) in order to achieve a relative humidity (RH) of 100%. At this point the air cannot hold more water in the gas form.

Answer:

ii cud givee uu an explanation for understandment for help if still don't understand im sowwyy thenn.

Explanation:

relative humidity is related to the partial pressure of water vapor in the air at 100% humidity the partial pressure is equal to the vapor pressure and no more water can enter the vapor phase.

Answer:

strawberry blueberry raspberry walang compound at element

Answer:

democritus

Explanation:

i looked it up

Answer: The thermal energy is spread out by the surrounding air.

Explanation:

got it right on test

The standard enthalpy of formation of substance in its standard state is zero.

Enthalpy is defined as a thermodynamic quantity that describes the energy of a system. For substances in their standard state, the enthalpy of formation is zero.

The standard state of a substance is defined as the state in which it is found under standard conditions.  The following substances has their standard ethalpy of formation as zero or not zero;

Zero enthalpy of formation           Non zero enthalpy of formation

Cl2(g)                                                     I2(s)

Br(g)                                                       Br2(l)

I2(g)                                                       Br2(s)

Hg(l)                                                       Hg(s)

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Considering the definition of molarity, the molar concentration is 0.294 [tex]\frac{moles}{liter}[/tex].

Molarity reflects the concentration of a solution indicating the number of moles of solute that are dissolved in a given volume.

The molarity of a solution is calculated by dividing the moles of the solute by the volume of the solution:

[tex]molarity=\frac{amount of moles of solute}{volume}[/tex]

Molarity is expressed in units [tex]\frac{moles}{liter}[/tex].

In this case, you know:

Replacing in the definition of molarity:

[tex]molarity=\frac{0.250 moles}{0.850 L}[/tex]

Solving:

molarity= 0.294 [tex]\frac{moles}{liter}[/tex]

Finally, the molar concentration is 0.294 [tex]\frac{moles}{liter}[/tex].

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Answer

At the crust

Explanation:

Mantle is far away from it unless its in a ocean.

Answer:

A mountain would form on the continental crust

Explanation:

Typically, a convergent plate boundary—such as the one between the Indian Plate and the Eurasian Plate—forms towering mountain ranges, like the Himalaya, as Earth’s crust is crumpled and pushed upward.

A detail report is very important for better decisions of President about economy.

It is very important to have such a detailed report on the economy because it helps the president as well as Congress to make better decisions about the imposing of taxes. It greatly helps and provides all information to the president and Congress so that they make better decisions about taxes and expenditures.

Without this detailed report, the Congress can't take right decisions about taxes and economy of the country so we can conclude that detail report is very important for better decisions of president about economy.

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Answer:

Ga₂O

Explanation:

Answer:

A state in which the concentrations of all the reactants and products remain constant with time

Explanation:

The statement which best describes chemical equilibrium is that the concentrations of all the reactants and products remain constant with time.

This is the situation in an object in which two or more forces or factors counter-influences because of them being constant.

In this scenario, the concentrations of all the reactants and products is constant which depicts the right choice.

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Answer:

ideal gas law. PV=nRT

Explanation:

pressure x volume = #moles x R (constant of 8.31) x temp

Answer:

i think it might be a giant astroid came and killed everything  sorry if im wrong

Explanation:

Answer:

spring and summer

Explanation:

Answer:

summer and spring

Explanation:

Symbol: O

Name: Oxygen

as number of protons + number of neutrons = atomic mass

8+8=16

The element is Oxygen (O) in the given element model.

The atomic number of an element is equal to the number of protons in its nucleus. Since the element in question has 8 protons, its atomic number is 8. Oxygen has an atomic number of 8, making it the element with 8 protons. Additionally, the atomic number determines the identity of an element; no other element has 8 protons in its nucleus.

The element's name is Oxygen, and its chemical symbol is O. Oxygen is a vital element in the Earth's atmosphere and is essential for supporting life. It is commonly found in the form of diatomic molecules (O2), which make up a significant portion of the air we breathe. Oxygen plays a crucial role in various biochemical and chemical processes, and its presence is essential for the respiration of most living organisms.

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Explanation:

at the Anode, Oxide ions lose electrons and produce Oxygen gas

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Answer:

brak syna 25 punto, syn 13

Explanation:

[tex]\underline{\boxed{\bf 15.05\times 10^{22} molecules\: of\: Carbon}}[/tex]

[tex]\underline{\boxed{\bf 6.023\times 10^{23} molecules\:of\: Hydrogen}}[/tex]

Refer to the attachment for calculations