Please help help helpppppppp

Answer:

1) during a phase change: particles overcome forces of attraction and temperature stays the same not during a phase change: temperature rises 2)Particle motion decreases, and electrostatic forces pull particles closer together.

3) Gases fill their container, showing that gas particles are not tied together and can move far apart.

Explanation:

Answer:OK im not 100% sure but it should be the right one

Explanation:

Given that –

We know that –

Then –

[tex]\qquad[/tex][tex]\bf\longrightarrow pOH = 14 -12.5 [/tex]

[tex]\qquad[/tex][tex]\sf \longrightarrow pOH = 1.5[/tex]

[tex]\qquad[/tex][tex]\sf \longrightarrow [OH^- ] = 10^{-1.5 }[/tex]

[tex]\qquad[/tex][tex]\bf \longrightarrow [OH^-] = 3.16 × 10^{-2}[/tex]

Now the number of moles of KOH need to ensure that concentration of Hydroxide anions is equal to –

[tex]\qquad[/tex][tex]\bf \longrightarrow 3.74\: L \times \dfrac{3.16× 10^{-2}}{1 \: L }[/tex]

[tex]\qquad[/tex][tex]\bf \longrightarrow 1. 18 × 10^{-1 }M [/tex]

Volume of the solution contains the need number of moles of Hydroxide anions –

[tex]\qquad[/tex][tex]\sf \longrightarrow \dfrac{ 1.18×10^{-1} \: moles \: OH^-}{0.826 \: moles \: OH^-}[/tex]

[tex]\qquad[/tex][tex]\sf \longrightarrow 0.143 L [/tex]

[tex]\qquad[/tex][tex]\sf \longrightarrow 0.143 \times 1000[/tex]

[tex]\qquad[/tex][tex]\pink{\bf\longrightarrow 143 mL }[/tex]

______________________________________

Answer:

Remember the black and red dots represented in the below animation are not molecules. They are just markers enabling us to visualize the local displacement of air particles and so, the rise and fall of pressure within the wave medium.

The air is made up of many tiny particles. When sound is created, the air particles vibrate and collide with each other, causing the vibrations to pass between air particles. The vibrating particles pass the sound through to a person's ear and vibrate the ear drum. Light travels much faster than sound through air.

Explanation:

Answer:

Answer:

N, B, Be, C

Explanation:

N (Nitrogen) has 14.0067 B (Boron) has 10.81 Be (Beryllium) has 9 and C (Carbon) has 12

The symbols for every chemical element that has atomic number greater than 3 and atomic mass less than 15.4 u are C, N, O, F, and Ne.

To find elements with atomic number greater than 3 and atomic mass less than 15.4 u, we'll consider the periodic table. Elements with atomic numbers 4 (Be) and higher meet the atomic number criterion. For the atomic mass, we'll look at elements with atomic masses below 15.4 u.

The chemical elements that fulfill both criteria are: Carbon (C) with atomic number 6 and atomic mass 12.01 u, Nitrogen (N) with atomic number 7 and atomic mass 14.01 u, Oxygen (O) with atomic number 8 and atomic mass 16.00 u, Fluorine (F) with atomic number 9 and atomic mass 18.99 u, and Neon (Ne) with atomic number 10 and atomic mass 20.18 u.

These elements meet the conditions of having atomic number greater than 3 and atomic mass less than 15.4 u. Therefore, the symbols for these elements are C, N, O, F, and Ne.

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Answer:

B. crest

Explanation:

The highest part of a wavelength is called the crest, meanwhile, the lowest part is the trough.

Answer:

b

Explanation:

it's highest because it have the most higher wave

Answer:

1)  a) 2 C2H2 +  3O2 -->  2CO2 +  2H2O

b) Combustion Reaction

c) Bonds will be broken on the reactant side which will require energy.

d) It agrees with the law of conservation of mass because there are the same amount of molecules of each element on both sides of the equation, meaning mass was not created nor destroyed.

2) a) 2Na + Cl2 --> 2NaCl

        Synthesis

   b) 2Fe + O2 --> 2FeO

        Synthesis

Hope this helps!

Explanation:

To calculate the atoms of an element in a given molecule, we need to multiply stoichiometry by the number that is written on the foot of that element. Therefore, the balanced equation is

2 C[tex]_2[/tex]H[tex]_2[/tex]+  3O[tex]_2[/tex] [tex]\rightarrow[/tex] 2CO[tex]_2[/tex]+  2H[tex]_2[/tex]O

Balanced equation is the one in which the total number of atoms of a species on reactant side is equal to the total number of atoms on product side. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, displacement reaction.

a) 2 C[tex]_2[/tex]H[tex]_2[/tex]+  3O[tex]_2[/tex] [tex]\rightarrow[/tex] 2CO[tex]_2[/tex]+  2H[tex]_2[/tex]O is the balanced equation

b)Reaction is a Combustion Reaction

c) energy is required for the breaking of bond.

d) It agrees with the law of conservation of mass as the number  of atoms of each element on reactant and product side is same.

Therefore, the balanced equation is

2 C[tex]_2[/tex]H[tex]_2[/tex]+  3O[tex]_2[/tex] [tex]\rightarrow[/tex] 2CO[tex]_2[/tex]+  2H[tex]_2[/tex]O

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Answer:

730 N

Explanation:

force =mass×acceleration

force= 73kg × 10 m/s

f=730N

Answer:

0.9 kg

2870000 uL

there is a conversion calculator online

The quantity of energy required to heat a piece of iron weighing 1.31 g from 25.0 degrees Celsius to 46.0 degrees Celsius is 2.93 calories.

The ability or power to perform tasks, such as the ability to move an object (having a certain mass) by exerting force.

Energy can exist in many forms, including electrical, mechanical, chemical, thermal, and nuclear, and it can also change its form.

The equation q = mcT, where m is the sample mass, c is the specific heat, and T is the temperature change, can be used to determine the amount of heat acquired or lost by a sample (q).

Q = mcΔT

Q = 1.31 g x 449 x 21° C = 12.26 joule

12.26 /1 x 1 cal / 4.189= 2.93 calories

Therefore, the quantity of energy required to heat a piece of iron is 2.93 cal.

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Answer: The density because it stays the same with any same liquids or solids or gas with whatever amount of it is added. It only changes if the matter of state is different or there is any environmental change.

Answer:

i did not find the amswer sorry

Explanation:

brain and heart froce acts between two chloramine

Answer:

Dispersion, Hydrogen-bonding, and Dipole forces act between two chloramine (NH2CI) molecules.

Explanation:

Dispersion is exerted between all molecules. Chloramine is polar, therefore dipole forces are present. The molecular geometry of chloramine (NH2Cl) is a trigonal pyramidal, therefore hydrogen-bonding forces are present.

Answer:

I hope it help you the wavelength is 1.9130E-28

Answer:

Thermosphere

Explanation:

More specifically the ionosphere, since the ionosphere is the lower part of the thermosphere.

Hope this helps!

Answer:

A

Explanation:

We are given that the molar mass of boron triflouride BF₃ is 67.81 g/mol. We want to determine the number of molecules of BF₃ in 2 g of BF₃.

Recall that there are 6.02 × 10²³ molecules in any mole of a substance. In other words, there are 6.02 × 10²³ BF₃ molecules in a mole of BF₃. Starting with the initial value, multiply:

[tex]\displaystyle \begin{aligned} 2\text{ g BF$_3$}&\cdot \frac{1\text{ mol BF$_3$}}{67.81 \text{ g BF$_3$}} \cdot \frac{6.02\times 10^{23} \text{ molecules BF$_3$}}{1 \text{ mol BF$_3$}} \\ \\ &= 1.776 \times 10^{22} \text{ molecules BF$_3$}\end{aligned}[/tex]

Hence, our answer is A.

*Perhaps it rendered the values incorrectly, but since we started with only 2 g of BF₃, our resulting calculation should only contain one significant digit. Hence, the correct answer should be 2 × 10²² molecules of BF₃.

The molecules of  BF₃ that are there in 2 g is 1.776 × 10²² molecules and the correct option is option A.

The mole is an amount unit similar to familiar units like pair, dozen, gross, etc. It provides a specific measure of the number of atoms or molecules in a bulk sample of matter.

A mole is defined as the amount of substance containing the same number of atoms, molecules, ions, etc. as the number of atoms in a sample of pure 12C weighing exactly 12 g.

Given,

Molar mass of BF₃ = 67.81 g/mol

Mass = 2g

Moles = mass / molar mass

= 2 / 67.81

= 0.029 moles

1 mole = 6.023 × 10²³

0.029 moles = 6.023 × 10²³ × 0.029

= 1.776 × 10²² molecules

Thus, the ideal selection is option A.

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Answer:

Answer: 0.66 hours

Explanation:

[tex]{ \rm{time = \frac{distance}{speed} }} \\ \\ { \rm{time = \frac{(950.5 \times 1000) \: m}{400 \: m {s}^{ - 1} } }} \\ \\ { \rm{time = {2376.25 \: s}}}[/tex]

• Remember 1 second accounts for 1/3600 hours

[tex]{ \rm{time = \frac{2376.25}{3600} }} \\ \\ { \rm{time = 0.66 \: hours}}[/tex]

The time taken by object  traveling at a speed of 400 m/s to reach 950.5 km distance is 0.66 hr or 39.6 min.

What is average velocity ?

Average velocity is given by the total distance covered by the object in total given time. SI unit of velocity is m/s.

Here in this question it is given that the object is travelling with speed v of 400 m/s and it is to find the time t to reach 950.5 km distance d.

it is known that 1 km = 1000 m

that is 950.5 km = 950500 m

Now, using the relation of speed-distance to find time t to reach 950.5 km distance :

[tex]\begin{aligned}v&=\frac{d}{t}\\t&=\frac{d}{v}\\&=\frac{950500}{400}\\&=2376.25 \text{ s}\end{aligned}[/tex]

Now converting 2376.25 sec into hrs by dividing it by 3600 we get :

2376.25/3600 = 0.66 hr or 39.6 min.

Therefore, the time taken by object to reach 950.5 km distance is 0.66 hr or 39.6 min.

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Answer:

2.Closed System: A closed system is a thermodynamic system where energy can be exchanged with its surrounding but not matter. Open System: Open systems can exchange matter with the surrounding. Closed System: Closed systems cannot exchange matter with the surrounding. Open System: The mass of the system will vary with time in open systems.

Explanation:

1.The particle model is the name for the diagrams used to draw solids, liquids and gases. In the model, the particles are shown as circles or spheres. However, the particles in ice, liquid water and steam look the same because they are all water, but in different states of matter. Why do we use the particle model in science?

3.An open system can be defined as a system which can exchange both matter and energy with the surrounding. For example, the earth can be recognized as an open system. In this case, the earth is the system, and space is the surrounding. Sunlight can reach the earth surface and we can send rockets to space.

Answer:

So, Percentage Composition of Aluminium = 2778×100%=34.62% (approx.) Percentage Composition of Oxygen = 3×1678×100%=61.54% (approx.)

Answer:

C 7.5 Moles of MgSO4

Explanation:

Answer:

because those are the only thermometers that are truly accurate for kelvins

Explanation:

The Kelvin temperature in thermometers is used by scientists because it provides a temperature where zero indicates the complete absence of thermal energy.

All thermometers have a scale on them that we use to find the temperature, known as a temperature scale. Kelvin proposed that the temperature interval from the ice point to the steam point be defined as 100° containing earlier centigrade scales.

Lord Kelvin had given an absolute temperature scale based on the Carnot cycle.  The zero point is 273.15 on Kelvin’s scale below that of the Celsius scale.

On the kelvin scale, Each division is called a Kelvin (K) and is equal to a degree on the Celsius scale. On the Celsius scale, zero degrees is the freezing point of water while on the Kelvin scale the zero point is at absolute zero temperature.

Therefore, 0 K is equal to - 273.15°C, and 0°C is equal to 273.15 kelvins. A mathematical expression that gives the relation between the Celsius and Kelvin scales:

Temperature (K) = Temperature (°C) + 273

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Taking into account the reaction stoichiometry and limiting reagent, 0.7977 grams of KClO₃ are formed from the  reaction of 2.50 g of KClO₄  with 150 mg of FeCl₂  in excess of H₂SO₄.

In first place, the balanced reaction is:

2 FeCl₂ + 13 KClO₄ + H₂SO₄ → 2 Fe(ClO₃)₃ + K₂SO₄ + 11 KClO₃ + H₂O

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

The molar mass of the compounds is:

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:  

The limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.

To determine the limiting reagent, it is possible to use the reaction stoichiometry of the reaction and a simple rule of three as follows: if by stoichiometry 1801.15 grams of KClO₄ reacts with 253.5 grams of FeCl₂, if 2.50 grams of KClO₄ react how many mass of FeCl₂ will be needed?

[tex]mass of FeCl_{2}=\frac{2.50 grams of KClO_{4} x253.5 grams of FeCl_{2}}{1801.15 grams grams of KClO_{4}}[/tex]

mass of FeCl₂=0.35 grams

But 0.35 grams of FeCl₂ are not available, 150 mg= 0.150 grams (being 1000 mg= 1 grams) are available. Since you have less mass than you need to react with 1801.15 grams of KClO₄, FeCl₂ will be the limiting reagent.

Then the following rule of three can be applied: if by reaction stoichiometry 253.5 grams of  FeCl₂ form 1348.05 grams of KClO₃, 0.150 grams of FeCl₂ form how much mass of KClO₃?

[tex]mass of KClO_{3}=\frac{0.150 grams of FeCl_{2}x1348.05 grams of KClO_{3} }{253.5grams of FeCl_{2} }[/tex]

mass of KClO₃= 0.7977 grams

Then, 0.7977 grams of KClO₃ are formed from the  reaction of 2.50 g of KClO₄  with 150 mg of FeCl₂  in excess of H₂SO₄.  

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Answer:

A and B.

Explanation:

Climate:

High temperatures and greater rainfall increase the rate of chemical weathering. Lower temperatures can break rocks to by freezing water inside of a rock cracks. When it freezes it expands the water and forces the crack of the rock to expand.

Rock Type:

Certain types of rock are very resistant to weathering. Igneous rocks, especially intrusive igneous rocks such as granite, weather slowly because it is hard for water to penetrate them. Other types of rock, such as limestone, are easily weathered because they dissolve in weak acids.

Answer:

Tortilla

Explanation:

Answer:

tortilla

Explanation:

Answer:

2. 389.15K , 3. 229.15K

Explanation:

K-273.15 = °C

Answer:

child stage.

Explanation:

they are more vubnlerabke at that stage