unknown substance's mass: 75.0g, unknown substances molar mass = 150.0 g/mol, Hfus = 5.0x10^3 J/mol, Hvap = 1.00 x 10^4 J/mol, unknown substance's specific heat (liquid) = 2.2 J/g, unknown substance's specific heat (gas) = 4.8 J/g, unknown substances's specific heat (solid) = 5.0 J/g; Calculate the amount of heat (in J) for the unkown sample as it is heated at a constant rate from 10.0c to 25.0c as it passes through each of the following regions: region uv

Answer:

The answer would be D.

: )

Explanation:

The number of gas molecules changes as the pressure inside oxygen tanks changes as they are filled. option D is correct.

Oxygen tanks are those in which the oxygen is filled in the liquid form by giving pressure to it with the help of a piston due to more pressure the molecules of oxygen become close.

As the molecule of the oxygen gas is closed to each other they are condensed and changes their state from a gaseous state to a liquid state.

By providing more pressure to the oxygen tank the gas molecules increases due to the decrease in the surface of the tank and molecules condense to liquid form.

Therefore, The number of gas molecules changes as the pressure inside oxygen tanks changes as they are filled. option D is correct.

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Explanation:

Hi,

The number of protons is equal to the atomic number. The number of electrons in a neutral atom is equal to the number of protons. So, in this case, you have 72 protons and 72 electrons.

I hope this helps :)

If an element has the atomic number 72, then the number of protons is also equal to 72. As it is clearly mentioned in the question that it is a neutral atom, which means the number of protons is equal to the number of electrons which is also 72.

An atomic number may be defined as the number of a chemical element in the modern periodic table through which the elements are systematically arranged in order of increasing the number of protons in the nucleus.

According to the context of this question, the atomic number of every element is always equal to the number of protons it has. While in a neutral atom, the number of electrons is equal to the number of protons. For calculating the number of neutrons, you have to subtract the atomic number from the atomic mass.

Therefore, there are 72 protons of an element whose atomic number is 72. The number of electrons is also 72.

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Answer:

there is nothing here

Explanation:

Option A. Boiling point.

Explanation:

When you heat the water, the water gets converts into gaseous form.

As you know that water is in liquid form. So, when you heat the water, the water molecules absorbs the heat and get dispersed from one another molecules. i.e., molecules go far from the other molecules as they absorbed heat.

The term describes the temperature at which a substance can change state from a liquid to a gas, is boiling point. Therefore, option A is correct.

The temperature at which a liquid's vapor pressure equals the pressure around it and the liquid transforms into a vapor is known as the boiling point of a substance. A liquid's boiling point varies depending on the atmospheric pressure in the area.

Boiling point and saturation temperature are synonyms. Sometimes the measurement's pressure serves as a definition for the boiling point. The International Union of Pure and Applied Chemistry was founded in 1982.

The boiling point of a sample can be calculated using a number of techniques, such as distillation, reflux, and a Thiele tube. The simplest approach makes use of a Thiele tube and has the benefit of requiring less than 0.5mL of substance.

Thus, option A is correct.

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Answer:

The energy required is 8660.96 J.

Explanation:

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

Sensible heat is the amount of heat that a body absorbs or releases without any changes in its physical state (phase change). This heat is given by the expression:

Q = c * m * ΔT

where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.

In this case, you know:

Replacing:

Q= 4.18 [tex]\frac{J}{g*C}[/tex] *74 g* 28 C

Solving:

Q= 8660.96 J

The energy required is 8660.96 J.

Answer:

hola no ablo inglés porfavor

Answer:

A

Explanation:

Got a calculation of 8.05297

Answer:

C. 3.6 m/s

Explanation:

I just took a test on a-pe-x and it was correct! :)

Explanation:

The particles of matter are continuously in motion due to which tehy collide with each other, and this creates a vibration in the solids

I hope it is correct ☺️

Explanation:

Sodium Chloride is neutral whereas hydrochloric acid is an acid. 2. Sodium Chloride is solid while hyrdochloric acid is a gas.

Answer:

The pressure of the gas would be 3.06 atm

Explanation:

Amonton's law states that the pressure is directly proportional to the absolute temperature of a gas under constant volume. The equation is:

P1 / T1 = P2 / T2

Where P1 is the initial pressure = 3.16atm

T1 is initial absolute temperature = 273.15 + 32.2°C = 305.35K

P2 is our incognite

And T2 is = 273.15 + 22.9°C = 296.05K

Replacing:

3.16atm / 305.35K = P2 / 296.05K

3.06 atm = P2

Explanation:

As we know that chloride ion is halogen. So it has seven valence electrons in its valence shell. Hence it gains one electron from others during chemical reaction to be stable. So Chloride ion have a negative charge of -1.

Hope it will help :)❤

Answer:

these species share a common ancestor

Explanation:

Answer:

Explanation:

We can first calculate [H⁺] by using the formula:

Now we proceed to calculate pH:

As the pH is higher than 7, the solution is basic.

Answer:

it is b, a stethiscope is the thing they put on your heart

Explanation:

Answer:

The particles move very fast and collide into one another, causing them to diffuse, or spread out, until they are evenly distributed throughout the volume of the container. When more gas particles enter a container, there is less space for the particles to spread out, and they become compressed.

Explanation:

Answer:

The rate at which the air temperature changes with height in the atmosphere surrounding a cloud or a rising parcel of air. The overall average rate is a decrease of about 6.5°C/km, but the rate varies greatly in different regions of the world, in different airstreams, and at different seasons of the year.

Answer:

(a) 0.294 mol silver = [tex]1.770 * 10^{23}[/tex]  

(b) 8.98 * 10-3 mol sodium chloride - [tex]5.407 *10^{23}[/tex]  

(c) 23.3 mol carbon dioxide  = [tex]1.403 * 10^{25}[/tex]

(d) 0.310 mol nitrogen (N2) = [tex]1.866 * 10^{23}[/tex]

Explanation:

In one mole there are [tex]6.022 * 10^{23}[/tex] atoms/molecules

(a) 0.294 mol silver = [tex]6.022 * 10^{23} * 0.294 = 1.770 * 10^{23}[/tex]  

(b) 8.98 * 10-3 mol sodium chloride - [tex]5.407 *10^{23}[/tex]  

(c) 23.3 mol carbon dioxide  = [tex]23.3 * 6.022 * 10^{23} = 1.403 * 10^{25}[/tex]

(d) 0.310 mol nitrogen (N2) = [tex]0.310 * 6.022 * 10^{23} = 1.866 * 10^{23}[/tex]

Answer:

T° freezing solution = -22.8°C

Explanation:

To solve this problem we apply, the Freezing Point Depression. This is a colligative property which its formula is:

T° freezing pure solvent - T° freezing solution = Kf . molality . i

i = Van't Hoff factor.

We have been informed is a nonionizing solute, so i = 1

Our solute is ethylene glycol, so le'ts determine the moles to get molality

388 g . 1 mol / 62.07 g = 6.25 moles

molality (m) = moles of solute /kg of solvent

We convert mass of solvent, water, to kg → 510 g . 1kg /1000g = 0.510 kg

6.25 mol /0.510kg = 12.25 m

We replace at formula → 0°C - T° freezing solution = 1.86°C/m . 12.25 m . 1

T° freezing solution = -22.8°C

Answer:

these metals are stored in kerosene because kerosene contains no water and protects these metals from being exposed to any moisture in the air that would cause these metals to react, potentially violently.

Answer:

3) Vapor pressure in atm = 0.13 atm

Explanation:

Answer:

Explanation:

what do u need to know

Answer:

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Explanation:

Answer:

A = 349 g.

Explanation:

Hello there!

In this case, since the radioactive decay kinetic model is based on the first-order kinetics whose integrated rate law is:

[tex]A=Ao*exp(-kt)[/tex]

We can firstly calculate the rate constant given the half-life as shown below:

[tex]k=\frac{ln(2)}{t_{1/2}} =\frac{ln(2)}{58year}=0.012year^{-1}[/tex]

Therefore, we can next plug in the rate constant, elapsed time and initial mass of the radioactive to obtain:

[tex]A=500g*exp(-0.012year^{-1} *30year)\\\\A=349g[/tex]

Regards!

Answer:

Answer:1 answer number 1

Explanation:

I know it’s E and A

Explanation: did you count it’s exactly 28, also the electrons are not visible.

Ps: I’m in 5th grade, what grade is this, if my suggestion was correct then holy crackers.