Which terms are used to identify pure substances?

Answer:

C)

atomic number

Explanation:

C)

atomic number is also the number of protons an atom has and this number will never change unlike number of neutrons or electrons.

Answer:

Try searching this on google

Explanation:

I might have an answer but I am not entirely sure sorry I really tried to help but there is also an app called socractic it also helps with questions

Once the temperature reaches 15,000,000 levels Celsius, nuclear fusion takes location in the center, or core, of the cloud. The high-quality heat given off by means of the nuclear fusion technique motives the gasoline to glow creating a protostar. This is the first step in the evolution of a star.

Answer:

what is scientific model

Explanation:

Answer:

(1) atomic numbers

Explanation:

The observed regularities in the properties of the elements on the periodic table are periodic functions of their atomic numbers.

The observed regularities in the properties of  the elements are periodic functions of their atomic numbers.

Modern periodic law states that "Properties of elements are a periodic function of their atomic number not by their atomic mass". Modern periodic law was proposed by Henry Moseley in 1913. Physical and chemical properties of elements depend on the number of electrons and their arrangement.

Thus properties of elements are periodic function of their atomic numbers and not atomic masses. If the properties of an element depend on number of proton and neutron then the properties are periodic function of their atomic mass so we can conclude that the observed regularities in the properties of  the elements are periodic functions of their  atomic numbers.

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Amorphous solids have two characteristic properties. When cleaved or broken, they produce fragments with irregular, often curved surfaces; and they have poorly defined patterns when exposed to x-rays because their components are not arranged in a regular array. An amorphous, translucent solid is called a glass

Answer:

Explanation:

Total volume of solution = 100 mL .

Total mass of the solution = 100 x 1.01 g

= 101 g

specific heat of solution = 4.184 J/g-°C

rise in temperature = 8.65  °C

heat released = mass x specific heat x rise in temperature

= 101 x 4.184 x 8.65

= 3655.35 J

= 3.655 kJ .

qsolution = 3.655 kJ .

The smallest unit that combines chemically or physically to form molecules and compounds is called an atom. They are composed of electrons and protons and neutrons in the nucleus.

The correct answer is:

Option d. To achieve a more stable electron configuration for both atoms.

This can be explained as:

Therefore to achieve stable configuration atoms bond with other atoms.

To learn more about atoms and stability follow the link:

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Explanation:

1) from the periodic table for example if u looking for K it is from the group 1A so the valancey = +1 that is mean it loses one electron to reach a stable state. and this applied for the 1A , 2A, 3A groups.

if u looking for N it is from group 5A so its valency is -3

so it gain 3 electrons to reach a stable state to complete its orbital to 8 electrons. this applied to 5A, 6A,7A

for the transition metals and simimetals other rules.

2) neutral if the element does not hold any charge like

H2, O2, N2, Fe, Au, Cu ...

isotope : if the 2 elements have same symbol and atomic number but they differ in the mass number because the have different numbers of neutrons.

if the element is charged then it is considered as an ion ex: Fe2+ then it is iron cation ( +ion)

F- then it is fluoride anion (-ion)

if u have any doubt just writ a comment ( ;

Answer:

option A: Atomic number

Explanation:

The atoms, isotopes and ions of magnesium doesn't change the atomic number of the magnesium.

For example, Isotopes are atoms that have the same number of protons but at the same time have different numbers of neutrons. This means that atomic number remains the same while mass number differs. Now, an ion is defined as an atom or molecule that has either a positive or negative charge.

So only option A is correct: Atomic number

Answer:

up down up down thats the pattern

Explanation:

Answer:

i think just these

NaCl

CaCl2

The activity series of metals is an empirical tool used to predict products in displacement reactions and reactivity of metals with water and acids in replacement reactions and ore extraction. It can be used to predict the products in similar reactions involving a different metal.

[tex]\huge\boxed{Option C}[/tex]

Calorimeter is device used for the measurement of heat. In a calorimeter we can use the temperature change of water to quantify an amount of heat.  A calorimeter just captures all the energy released (or absorbed) by a reaction in the water. So Option A and B are wrong as calorimeter don't have anything to do with providing the heat or letting the the heat in, as it is the insulated calorimeter too.

In the formation of any bond there is equal amount of heat required as to break that bond. It means Energy released in the making of bond is equal to the energy required in the breaking of the bond. So Option D is wrong as it says we need more energy in making then breaking.

Enthalpy is the total heat content of the system. As we provide energy to the reactants and the product is formed, so The enthalpy(heat content) of product is more than the Enthalpy of the reactant, Thus Option C is correct.

Enthalpy is denoted by H or Q, its formula is,

                                       H = U + PV

Where,

           U is internal energy

           PV is equals to Work done ; P = Pressure, V = Volume

Several erosive agents affect the soil structure and composition. Selecting sandstone, 100cm/yr precipitation, 20ºC, and 50% vegetation cover, there is 45% of eroded rock. The general landscape appearance changes little.

Erosion is the process of fertile soil loss.

It is due to several external agents that damage the ground and drag the exposed material from the superficial layer of the earth.

Some of the erosive agents are water, wind, ice, gravity, or animal trampling.

Three main phases compose the erosion process

a) particles landslide

b) transport of superficial free particles

c) deposit/sedimentation.

Soil erosion leads to its degradation.

Since its regeneration is extremely slow, erosion produces several negative events that lead to soil loss as a non-renewable natural resource.

All the erosive agents act together modifying the soil composition, shape, and structure. The loss of plant cover increases, even more, the erosive effects.

Soil vegetation cover reduces erosion because the aerial part of the plant protects the surface, while roots protect the ground structure and retain water.

The less vegetation cover there is, the more exposed the soil is, and the more severe effects the erosive agents cause.

In the exposed example, we have many variables to control and analyze their effect on soil erosion. Before playing the simulation, I chose the followings

Under these conditions, after 20,000 years there was 0.42 km³ of eroded rock.

The general aspect of the landscape changed very little, suggesting that erosion occurs slowly.

Probably, if we change the values of the variables, we will observe a sharper change. For instance, if we take the vegetable cover to less than 20% and increase the levels of precipitation and temperature, we will observe a faster erosion process and a wider affected area.

You can learn more about erosion at

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Molar mass

= Atomic mass of Na + Atomic mass of N + Atomic mass of O3

= 23 + 14 + (16×3)

= 23 + 14 + 48

= 85 g per mole

Answer:

Yes, both are molecules

Explanation:

A molecule is the smallest particle of a substance that can exist alone and still retain the chemical properties of that substance.

Molecules are usually made up of two or more atoms of the same or different elements chemically combined together. for example, two atoms of hydrogen will combine to form a molecule of hydrogen gas. Similarly, an atom of hydrogen can combine with an atom of chlorine to form hydrogen chloride gas molecule.

Ozone is a molecule which consists of three atoms of oxygen chemically combined together.

Similarly, water is a molecule composed of two atoms of hydrogen and an atom of oxygen chemically combined together.

Answer:

nerve cell, nervous tissue, brain, nervous system, human.

Explanation:

The order is from the simplest to the most complex, within the simplest would be the cellular structure, then the organs come, then systems (a set of organs in multidirectional operation among them) and finally the human, which is a set of systems .

Answer:

Depends since Chemical equation is not written clearly...

Explanation:

if if the comma represents an equal sign then I would assume that this would be a single replacement... however if this is all one equation I would assume it is a double replacement.

The type of chemical reaction shown in the question is a: A. Single replacement.

A chemical reaction can be defined as a chemical process involving the continuous transformation (rearrangement) of either the ionic, atomic or molecular structure of a chemical element, especially through the breakdown and formation of chemical bonds, in order to produce a new chemical compound.

In Chemistry, there are five (5) main types of chemical reaction and these include;

A single-replacement reaction is also referred to as a single-displacement reaction and it can be defined as a type of chemical reaction wherein a single (one) chemical element of the reacting chemical compound is replaced (substituted) by a similar chemical element.

Basically, a single-replacement reaction typically involves a single element ([tex]O_2[/tex]) replacing another element ([tex]Cl_6[/tex]) within a chemical compound ([tex]SeCl_6[/tex]).

[tex]SeCl_6+O_2[/tex]  ----> [tex]SeO_2 + 3Cl_2[/tex]

In conclusion, the above chemical reaction is a single-replacement reaction because oxygen gas replaces the chlorine molecules in selenium hexachloride.

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Answer:

Gravitational potential energy may be converted to other forms of energy, such as kinetic energy. If we release the mass, gravitational force will do an amount of work equal to mgh on it, thereby increasing its kinetic energy by that same amount (by the work-energy theorem).

Explanation:

MW of gas : 124.12 g/mol

Density is a quantity derived from the mass and volume  

Density is the ratio of mass per unit volume  

With the same mass, the volume of objects that have a high density will be smaller than objects with a smaller type of density  

The unit of density can be expressed in g/cm³ or kg/m³  

Density formula:  

[tex]\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}[/tex]

ρ = density  

m = mass  

v = volume  

glass vessel wieight = 50 g

glass vessel + liquid = 148 ⇒ liquid = 148 - 50 =98 g

volume of glass vessel :

[tex]\tt V=\dfrac{m}{\rho}=\dfrac{98}{0.989}=99.1~ml[/tex]

An ideal gas :

m = 50.5 - 50 = 0.5 g

P = 760 mmHg = 1 atm

T = 300 K

[tex]\tt PV=\dfrac{mass(m)}{MW}.RT\\\\MW=\dfrac{m.RT}{PV}\\\\Mw=\dfrac{0.5\times 0.082\times 300}{1\times 0.0991}=124.12~g/mol[/tex]

Answer:An atom

Explanation:

Because  molecules more spread out and have things that connnect them and are not bunched up togoether

And Atoms are all packed up like in the picture

Hope this helps!:D

The diagram shown is that of a molecule as it is made up of two different kinds of atoms.

An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.

The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.

Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.

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#SPJ2

Answer:

f = 3.53×10⁵ s⁻¹

Explanation:

Given data:

Energy of photon = 2.34×10⁻²⁸ J

Frequency = ?

Solution:

h = 6.63 ×10⁻³⁴

Formula:

E = hf

2.34×10⁻²⁸ J = 6.63 ×10⁻³⁴ × f

f = 2.34×10⁻²⁸ J /  6.63 ×10⁻³⁴ Js

f = 0.353×10⁶ s⁻¹

f = 3.53×10⁵ s⁻¹

Answer:0,25 g/cm3 creo

Explanation:densidad es masa entre volumen

Answer:

0.25 g/cm³

Step-by-step explanation:

As we know

The density is given by

Density = Mass / Volume

Putting the values

Density = 5g / 20 cm³

Density = 0.25 g/cm³

Sorry if wrong I'm not great at math!

Answer:

9 moles of O²

Explanation:

Hope this helped,

Philip

Brainliest always appreciated! <3

There is differ motion you go through the day translational, rotational, periodic, and non periodic motion.

Hope this helped you

Sorry if it wrong