Define atomic numbers and mass numbers

Answers

Answer 1
Atomic numbers is the number of a chemical element in the periodic table and the mass number is the total number of protons and neutrons in an atom
Answer 2

Answer:

1). Atoms of each element contain a characteristic number of protons. In fact, the number of protons determines what atom we are looking at (e.g., all atoms with six protons are carbon atoms); the number of protons in an atom is called the atomic number.

2) In contrast, the number of neutrons for a given element can vary. Forms of the same atom that differ only in their number of neutrons are called isotopes.

3) Together, the number of protons and the number of neutrons determine an element’s mass number: mass number = protons + neutrons. If you want to calculate how many neutrons an atom has, you can simply subtract the number of protons, or atomic number, from the mass number.


Related Questions

Consider the reaction where barium sulfate can be prepared from 2.76 mol of sodium sulfate and excess barium acetate. Sodium acetate is the other product
1.write the balanced MOLECULAR reaction.
2.write the balanced total ionic equation.
3.write the balanced net ionic equation.

Answers

Answer:

1. Na2SO4(aq)+C4H6BaO4(aq) --> BaSO4(s) + 2C2H3NaO2(aq)

2. 2Na^+1(aq) + SO4^-2(aq) + 4C^+4(aq) + 6H^+1(aq) + Ba^-2(aq) + 4O^-2(aq) --> BaSO4(s) + 2C^-4(aq) + 2H^+1(aq) + 3Na^+1(aq) + 2O^-2(aq)

3. Ba^+2(aq) + SO4^-2(aq) --> BaSO4(s)

Explanation:

need help with this question asap :)
-20 points!..

Answers

the answer is d, ive had this before

What is the molecular geometry if you have a double bond, a single bond and 1 lone pair around the central atom?

Answers

Answer:

4 pairs are needed for the bonds, leaving 1 lone pair. Each double bond uses 2 bond pairs and can be thought of as a single unit. There are 2 double bond units and 1 lone pair, which will try to get as far apart as possible - taking up a trigonal planar arrangement.

A Carnot engine takes 2000 j of heat from a reservoir at 500 k, does some work and discards some heat to a reservoir at 350k . how much work does it do, how much heat is discarded, and what is it's efficiency?​

Answers

Answer:

Explanation:

The Carnot engine is a theoretical or conceptual heat engine that has a higher efficiency than any practical or theoretical heat engine working between the same temperature range. The theoretical efficiency of a Carnot engine is considered as the highest efficiency and no practical heat engines can operate at that efficiency. A Carnot engine draws heat energy, performs useful work and the leftover energy is released from the working substance. According to the second law of thermodynamics, there must be a temperature gradient between the heat energy drawing point and release point of the heat engine.

Which of the following are used to administer liquid medications orally? O a) Syringes b) Vials c) Suppositories d) Droppers e) Teaspoons

Answers

Answer:

D

Explanation:

How many hydrogen atoms are in 5CH3COOH?

Answers

Answer:   This formula indicates that a molecule of acetic acid (Figure 2.21) contains two carbon atoms, four hydrogen atoms, and two oxygen atoms.

Explanation:

Hola alguien me puede ayuda esto no se como

Answers

Para convertir c a kelvin
K=c +273
Ósea que en vez de c vas a poner el número

Para de Kevin a Celsius
C=k - 273

What is the process of solar nuclear fusion?

Answers

Answer:

base sa research po

Explanation:

In the core of the Sun hydrogen is being converted into helium. This is called nuclear fusion. It takes four hydrogen atoms to fuse into each helium atom. During the process some of the mass is converted into energy.

Answer:

Hydrogen atoms are fused into deuterium, then helium-3, then helium-4, each step giving off large amounts of energy.

Explanation:

Because that's how it works :D

An unknown solution contains several chemical substances. By following a series of steps in a procedure, each of these substances can be isolated. Which of the following methods would be most appropriate for showing the steps needed to separate the substances?

A. Draw a diagram of apparatus used.
B. Create a flowchart of the various steps.
C. Build a model of the various atomic structures.
D. Construct a graph showing the times needed for each step.

Answers

Answer:

Create a flowchart of the various steps.

Explanation:

Answer:

A.

Explanation:

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Determine the frequency of light with a wavelength of 2.672 x 10^-7cm

Answers

Answer:

Determine the frequency of light with a wavelength of 2.775⋅10−7 cm. Answer in units of Hz?❤


What kind of elements form covalent compounds?

Answers

Well, covalent bonding usually occurs between non-metals.
So some examples of covalent compounds may include:

O2 – oxygen.
Cl2 – chlorine.
H2 – hydrogen

as these all occur between non metals.

Answer:

Covalent bonds usually occur between nonmetals. For example, in water (H2O) each hydrogen (H) and oxygen (O) share a pair of electrons to make a molecule of two hydrogen atoms single bonded to a single oxygen atom. In general, ionic bonds occur between elements that are far apart on the periodic table.

Which of the following shows the valency of 1?

a) nitrogen
b) carbon
c) oxygen
d) sodium​

Answers

[tex]\huge \bf༆ Answer ༄[/tex]

The element having valency of 1 is ~

Sodium (Na)

Answer: Pretty sure this is d.) sodium

Explanation:

the size of camphor kept in store house gradually decrease in size after few а days? ​

Answers

Answer:

Because it goes through the process of sublimation.

Explanation:

Which example accurately describes a solution? (1 point)

Nonpolar oil molecules dissolve in water, which is polar.

Polar sugar molecules dissolve in water, which is polar.

Nonpolar fat molecules dissolve in water, which is polar.

Polar sugar molecules dissolve in oil, which is nonpolar.

Answers

The example which accurately describes a solution is; Polar sugar molecules dissolve in water, which is polar.

According to the question:

We are required to determine Which example accurately describes a solution.

The formation of a solution requires that the solvent and solute be of the same polarity.

In essence, the example which accurately describes a solution is; Polar sugar molecules dissolve in water, which is polar.

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Answer:

Polar sugar molecules dissolve in water, which is polar.

Explanation:

I did the Exam and got it right!

A gas sample occupies 8.76 L at a temperature of 37°C. What is
the volume if the temperature is lowered to 0°C at constant
pressure?

Answers

Answer:

A.

Explanation:

what is the name of the compound N2O5​

Answers

Answer:

Dinitrogen pentoxide also known as Nitrogen pentoxide or nitric anhydride (these are all the same thing just different names people call them)

It’s Dinitrogen pentoxide

A student reads that sodium atoms (Na) react with chlorine (Cl2) molecules to form the compound sodium chloride (NaCl). Which model should the student make to satisfy the Law of Conservation of Matter for the formation of sodium chloride, in simplest form?

Answers

Answer:

c

Explanation:

Law of Conservation of Matter for the formation of sodium chloride, in simplest form would be obeyed when 2 moles of sodium react with 1 ,mole of chlorine to form 2 moles of sodium chloride.

What is law of conservation of matter?

According to law of conservation of matter, it is evident that matter is neither created nor destroyed rather it is restored at the end of a chemical reaction .

Law of conservation of matter and energy are related as matter has mass and mass and energy are directly proportional which is indicated by the equation E=mc².Concept of conservation of matter is widely used in field of chemistry, fluid dynamics.

Law needs to be modified in accordance with laws of quantum mechanics under the principle of mass and energy equivalence.This law was proposed by Antoine Lavoisier in the year 1789.

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What is the balanced net ionic equation when aqueous solutions of Pb(NO3)2 and KBr are mixed and form a product

Answers

Answer:

KBr+Pb(NO3)2=? is an equation you can use.

Explanation:

what is wrong with the statement? "because there are no common factors in the molecular formula, k2co3 is also the empirical formula of potassium carbonate"

Answers

The empirical formula is the same as the molecular formula because the ratio of atoms in the compound correspond to the number of atoms of each element in the compound.

The empirical formula of a compound shows the ratio of atoms of each element in the compound while the molecular formula shows the number of atoms of each element in the compound.

For the compound, K2CO3, the empirical formula is the same as the molecular formula because the ratio of atoms in the compound correspond to the number of atoms of each element in the compound. It has nothing to do with common factors.

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A compound contains 25.94%N and 74.06% O by mass whats the empirical formula

Answers

Answer:

the answer is NO or nitric oxide.

hope this helps, love. have a good day

Explanation:

Empirical formula is the simplest whole number ration of elements in a compound. Molecular formula is n times the empirical formula, where n is integers 1,2,... Therefore, the empirical formula is NO[tex]_2[/tex].

What is Empirical formula?

Empirical formula gives the proportion of the element that is present in a compound. It does not give information about the actual number or the arrangements of the atoms.

The relation between molecular formula and empirical formula can be given as

n= molecular formula÷ empirical formula

Number of gram atoms in compound and divide by smallest Number of gram atoms in compound

N=(25.94%)÷14=1.85/1.85=1

O=( 74.06% )÷16=4.62/1.85=2

The atomic ratio is 1:2

Whole number N:O is1:2

Empirical formula corresponding to this whole number is NO[tex]_2[/tex].

Therefore, the empirical formula is NO[tex]_2[/tex].

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The side of a cube is found to be 127.58 mm and its mass is found to be 7.3 kg. Determine the density of this cube in g/mL.

Answers

Answer:

3.5154 g/mL

Explanation:

You will need to use the equation Density = Mass/Volume. You are given mm(can be used to find volume) of a cube and kg(mass). Since your answer is in g and mL we should convert it to those sizes. First we want cm so we will divide the 127.58 mm to cm getting 12.758 cm. We want to cube it since we are finding the whole area of a cube( 12.758*12.758*12.758) which will equal 2076.58 cm^3. We know that 1 mL is equal to 1 cm^3, so we can take our 2076.58 cm^3 and label them as mL(which is what we want). Then we know that there are 1000g in 1 kg, so if we multiply the 7.3 kg, we get 7300g. Finally use the equation Density = Mass/Volume to get your answer. 7300g/2076.58mL = 3.5154 g/mL.

Hope this helps!

How are prisms and raindrops alike?
They are both transparent.
They both reflect white light.
They are both translucent.
They both refract white light.

Answers

they both refract white light.

Answer:

They both reflect white light.

Explanation:

How raindrops and prism are similar?

Raindrops and prisms are similar because they both cause light to bend when it enters a prism or raindrop. When light enters a raindrop it causes the light to bend (refract) and separates the white lights into different wavelengths, allowing us to see the individual colors of the rainbow.

What is the total pressure exerted by a mixture containing two gases if the partial pressure of one gas is 70 kPa and the partial pressure of the other gas is 30 kPa?

Answers

Answer:

The total pressure of a mixture of gases can be defined as the sum of the pressures of each individual gas: Ptotal=P1+P2+… +Pn. + P n . The partial pressure of an individual gas is equal to the total pressure multiplied by the mole fraction of that gas.

Explanation:

hope this helps have a wonderfull day!

Anyone mind answering this

Answers

Its option A: double replacement

list 2 underlying causes of water pollution

Answers

Answer:

industrialization and rapid human population growth.

Explanation:

Hope this helps

Answer:

Water Pollution

Explanation:

Dumping industrial waste in ocean

Accidental oil leakages

Of the following, ________ is the most volatile. Select one: C2F6 C2H6 C2I6 C2Cl6 C2Br6

Answers

Answer:

C2Br6

because bromine is a liquid volatile

According to the forces of attraction and boiling point C₂Br₆ is most volatile as its boiling point is very low.

What are forces of attraction?

Forces of attraction  is a force by which atoms in a molecule  combine. it is basically an attractive force in nature.  It can act between an ion  and an atom as well.It varies for different  states  of matter that is solids, liquids and gases.

The forces of attraction are maximum in solids as  the molecules present in solid are tightly held while it is minimum in gases  as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.

The physical properties such as melting point, boiling point, density  are all dependent on forces of attraction which exists in the substances.

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1.
How many moles of NaCl are in 1.5L of 0.25 M solution?

Answers

Answer:

0.375 moles

Explanation:

no of moles =vol×molarity

A plant uses the energy from sunlight to create oxygen and glucose from carbon dioxide and water which statement is true about the changes that have occurred

Answers

Answer:

The correct answer choice is A. A chemical change has occurred because new compounds have been produced.

Explanation:

A physical change is defined as a change in which there is alteration in shape, size etc. No new substance gets formed in these reactions.Example: Melting of ice A chemical change is defined as a change in which a change in chemical composition takes place. A new substance is formed in these reactions.Example: photosynthesis

Photosynthesis is the process used by plants, algae and certain bacteria to convert energy from sunlight and turn it into chemical energy in the form of glucose which is used a s a source of energy by many organisms.

Thus the true statement is a chemical change has occurred because new compounds have been produced.

To calculate the atomic mass of an element, the percent
abundance of etch isotope is needed. ?

Answers

Answer:

List the known and unknown quantities and plan the problem. Change each percent abundance into decimal form by dividing by 100. Multiply this value by the atomic mass of that isotope. Add together for each isotope to get the average atomic mass

Explanation:

Define the terms (a) sedimentation ( b )decantation​

Answers

Answer:

Sedimentation: Sedimentation is the process of allowing particles in suspension in water to settle out of the suspension under the effect of gravity.Decantation: Decantation is a process for the separation of mixtures of immiscible liquids or of a liquid and a solid mixture

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