an atom has 79 protons, 78 electrons and a mass number of 118. how many neutrons does this atom have​

Answers

Answer 1

Answer:

39

Explanation:

Electrons weigh almost nothing, so their mass doesn't really matter for these types of problems. Just subtract 118-79 to find the remaining mass which is for the neutrons.


Related Questions

The force of 20 N acts upon a 5kg block. What is the acceleration of the block?
100 m/s/s
4 m/s/s
O 25 m/s/s
O 0.25 m/s/s

Answers

Answer:

The answer is 4 m/s²

Explanation:

The acceleration of an object given it's mass and the force acting on it can be found by using the formula

[tex]a = \frac{f}{m} \\ [/tex]

where

a is the acceleration

f is the force

m is the mass

From the question

f = 20 N

m = 5 kg

We have

[tex]a = \frac{20}{5} \\ [/tex]

We have the final answer as

4 m/s²

Hope this helps you

Help me this, I only have 10 minutes to answer!!!!

Answers

Answer:sedimentary

Explanation:

The process by which vesicles move substances out of a cell is

Answers

Exocytosis describes the process of vesicles fusing with the plasma membrane and releasing their contents to the outside of the cell, as shown in the Figure below. Exocytosis occurs when a cell produces substances for export, such as a protein, or when the cell is getting rid of a waste product or a toxin.

If a feather and in Marble are dropped at the same time from the same height explain. Which object would hit the floor first based on air resistance?​

Answers

Answer:

the marble would hit the floor first because the feather would be effected by air resistance

How are contact forces and non-contact forces similar?

Answers

Answer:

Difference between Contact and Non-Contact Forces

There is no field linked with the contact force. There is always a field linked with non-contact force. The frictional force is an example of a contact force. Gravitational force is an example of a non-contact force.

Explanation:

And it is physics not chem.

Hope this helps u

Crown me as brainliest:)

Calculate the density of an
object with a mass of 20 g
and a volume of 2.3 mL.

Answers

Answer:

8.7g/mL

Explanation:

I used the density formula to solve. d=m/v= 20g/2.3mL

Answer:

8.7 g/ml

Explanation:

the formula for density is D = M/V


In a mixture of bromine-79 and bromine-81 isotopes. An atom of bromine-79 contains?

Answers

Answer:

Bromin-79

Explanation:

The isotope bromine-79 will contain 35 protons, 35 electrons and 44 neutrons.

How many grams of Al are needed to react with 91.8 grams of FeO
3FeO + 2Al —> 3 Fe +Al2O3

Answers

Answer:

Ans : 22.86 gm of Aluminium

Solution,

                        3FeO + 2Al ---> 3 Fe + [tex]Al_{2}O_{3}[/tex]

Given                   3          2                    

Find                    1.27       x

By the given gms of FeO find its mole and put the moles in the find,

                         

                                       [tex]n = \frac{given mass}{molecular mass}[/tex]

                  Given mass of FeO is 91.8

                   Molecular mass of FeO is 71.8

                                           

                                         n = [tex]\frac{91.8}{71.8}[/tex]  

                                         n = 1.27 moles of FeO  

Now solve for x,

                            [tex]x = \frac{2 x 1.27}{71.8}[/tex]

                             x = 0.85 moles

These are just moles of Aluminium that we need to react with FeO, so to find Grams of Aluminium we need,

                                Mass = moles x molecular mass

                                Mass = 0.85 x 27(atomic mass of Al)

                                Mass = 22.86 grams of aluminium is what we need

                                         

How is light emitted

Answers

Answer:

The frequencies of light that an atom can emit are dependent on states the electrons can be in. When excited, an electron moves to a higher energy level or orbital. When the electron falls back to its ground level the light is emitted.

Answer:

A Light is produced when an electron moves from a higher to a lower energy level.

Explanation:

Which elements is the most reactive on this table?

Answers

Answer:

alkali metals

Explanation:

alkali metals only have one valence electron, meaning they are extremely reactive. they are considered the most reactive on the periodic table.

please help me i don’t know the answer to this!!!!!!

Answers

Answer: Lithium and Ethanol

Explanation: As lithium and ethanol both have a density of under

1.000g/ml, they can be supported by the water. Blood and Magnesium are denser than the water and will therefore sink as the water can not support it them.

Imagine there is technology that allows scientists to see all of the movement of molecules inside living things. A scientist points this machine at the stem of a vascular plant and sees glucose molecules being transported to various parts of the plant. The scientist is looking at the movement of molecules through

the xylem.
the phloem.
the roots.
the cuticle.

Answers

Answer: C

Explanation: I looked it up lol

i need help please help me now please

Answers

The answer is C, balanced

What is the name for the type of graph shown in the image below?
Box-and-whisker
Histogram
Line
Scatter plot

Answers

Answer:

Scatter plot

Explanation:

Because the plot is scattered all over the place

1.What do you call the rate of doing work?
A. Energy
B. Time
C.Power
D. Work

2.What is the unit of power?
A. Joule
C. Newton
B. Second
D. Watt

3.How much power is required to lift a 30ON chair, as high as 0.20 in 2s?
A.1 W
C. 3 W
B. 7W
D. 15 W

4.How much power is required to raise a 30 kg crate with a vertical distance of 6m in a time of 4
Seconds?
A. 45 WV
C 52.5 W
B. 385 W
D. 441 W

5. A job is done slowly, and an iden tical job is done quickly. Both jobs require the same amount of_______
but different amounts of_________
A. energYy, work
B. work, energy
Choose the correct two words respectively.
C. power, work
D. work, power

6.What is work?
A. Force muitiplied by time
C. Force multiplied by distance
B. Force per unit of time
D. Force divided by distance

7.What is the unit of work?
A Joule
B. Second
C. Newton
D. Watt

8.Power can be increased by______
A. decreasing the force applied by an object.
B. decreasing the work done on the object
C.inereasing the time in which the work is done.
D. decreasing the time in which the work is done.



Please help​

Answers

Answer:

1. c

2. d

3. c

4. d

5.

6. a

7. a

8.

What is the temperature, in degrees Celsius, of a 10.5 grams sample of Neon gas confined to a volume of 2.50 L at a pressure of 1.00 atm.

Answers

Answer:

–215 °C

Explanation:

From the question given above, the following data were obtained:

Mass of Ne = 10.5 g

Volume (V) = 2.50 L

Pressure (P) = 1 atm

Temperature (T) =?

Next, we shall determine the number of mole present in 10.5 gof Neon, Ne. This can be obtained as follow:

Mass of Ne = 10.5 g

Molar mass of Ne = 20 g/mol

Mole of Ne =.?

Mole = mass /Molar mass

Mole of Ne = 10.5 / 20

Mole of Ne = 0.525 mole

Next, we shall determine the temperature of the sample of Neon, Ne. This can be obtained as follow:

Volume (V) = 2.50 L

Pressure (P) = 1 atm

Number of mole (n) = 0.525 mole

Gas constant (R) = 0.0821 atm.L/Kmol

Temperature (T) =?

PV = nRT

1 × 2.5 = 0.525 × 0.0821 × T

2.5 = 0.525 × 0.0821 × T

Divide both side by 0.525 × 0.0821

T = 2.5 / (0.525 × 0.0821)

T = 58 K

Finally, we shall convert 58 K to degree celsius (°C). This can be obtained as follow:

T(°C) = T(K) – 273

T(K) = 58 K

T(°C) = 58 – 273

T(°C) = –215 °C

Thus, the temperature of the sample of Neon gas is –215 °C.

How many elements are in H2CrO4

Answers

There are 7 elements

Answer:

3 elements

Explanation:

The elements are:

- Chromium

- Hydrogen

- Oxygen

Which part of a flower can make eggs

Answers

Within the flower, sperm cells are produced by pollen at the tips of stamens, while egg cells develop in ovules, tiny structures embedded in the ovary at the base of the pistil.

Answer:Within the flower, sperm cells are produced by pollen at the tips of stamens, while egg cells develop in ovules, tiny structures embedded in the ovary at the base of the pistil.

I didn't realize the person up top had the same answer give them the brainliest! :)

Right amount of gravity​

Answers

the answer is: 9.80665

But gravity is the earths mass that holds you to the ground and if we had no gravity we would just be floating and not walking on ground

Convert 3.4 moles of sodium oxalate into grams. Show all your work .

Answers

Answer:

m = 455,6 g

Explanation:

The mass can be determined by calculating the amount of substance times the molar mass:

m = n * M

To do this, you first have to calculate the molar mass of sodium oxalate. It is made up of the molar masses of the individual atoms. The molecular formula of sodium oxalate is:

[tex]Na_{2}C_{2}O_{4}[/tex]

M(Na) = 23 g/mol; M(C) = 12 g/mol; M(O) = 16 g/mol

M(Na2C2O4) = 2 * M(Na) + 2 * M(C) + 4 * M(O)

M(Na2C2O4) = 2 * 23 g/mol + 2 * 12 g/mol + 4 * 16 g/mol

M(Na2C2O4) = 134 g/mol

m = n * M

m = 3,4 mol * 134 g/mol

m = 455,6 g

1. A camper named Bob ran into aliens on a trail. Bob made friends with the aliens so he could
steal their treasure of 1 zygot.
1 zygot = 3 trigots
3 trigots = 2 bigots
4 bigots = 1 gram gold
How many grams of gold did Bob take from the aliens?

Answers

Answer : The number of grams of gold Bob take from the aliens will be 0.5.

Explanation :

As we are given that:

1 zygot = 3 trigots

3 trigots = 2 bigots

4 bigots = 1 gram gold

Now we have to determine the number of grams of gold Bob take from the aliens.

The number of grams of gold Bob take from the aliens will be equal to:

[tex]\frac{1\text{ zygot}}{1}\times \frac{3\text{ trigots }}{1\text{ zygot}}\times \frac{2\text{ bigots }}{3\text{ trigots }}\times \frac{2\text{ gram gold}}{4\text{ bigots }}[/tex]

= [tex]\frac{6}{12}[/tex] gram gold

= [tex]\frac{1}{2}[/tex] gram gold

=  0.5 gram gold

Hence, the number of grams of gold Bob take from the aliens will be 0.5.


A piece of metal is composed of atoms. Each atom in the metal contains 29 protons. How is the metal classified?

Answers

Answer:

The metal is Copper

Explanation:

Matter is composed of atoms, which is the smallest indivisible particle of an element. The atom of an element consists of three subatomic particles namely: proton, electron and neutron etc.

The proton, which is the positively charged particle, is equal to the electron, which is the negatively charged particle. The proton number of the atom is the ATOMIC NUMBER of an element.

In the periodic table, the element with atomic number 29, which also means proton number 29 is Copper (Cu).

Calcium reacts with oxygen to make calcium oxide, CaO. What is the theoretical yield (g) of CaO(s) that could be prepared from 7.75 g of Ca(s) and 2.44 g of O2(g)

Answers

Answer:

Explanation:

2Ca    +    O₂   =    2CaO

80 g     32 g         112 g

given amount of Ca = 7.75 g

it will require oxygen =  32 x 7.75 / 80 = 3.1 g

but available oxygen = 2.44 so oxygen is the limiting reagent .

32g oxygen reacts with calcium to give 112 g of calcium oxide

2.44 gram of oxygen reacts with calcium to give 112 x 2.44 / 32 of CaO .

= 8.54 gram .

Theoretical yield of CaO = 8.54 gram.

A chef fills a 60 mL container with 52.2 g of cooking oil. What is the density of the oil?

Answers

Answer:

The answer is 0.87 g/mL

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\ [/tex]

From the question we have

[tex]density = \frac{52.2}{60} \\ [/tex]

We have the final answer as

0.87 g/mL

Hope this helps you

Write the equation for the dehydration of the CoCl2 hydrate

Answers

Answer:CoCI2+6H20
......hope this helped

What is the mean of the data set [3, 2, 2, 12, 6, 5, 14,4)?
O2
O 7

Answers

Answer:

the mean is 6 but you don't have that as an option.

Explanation:

the mean is the average.

to find the mean you have to add all of your data first

3 + 2 + 2 + 12 + 6 + 5 + 14 + 4 = 48

then you have to divide your answer by how many numbers there are in total.

48 / 8 = 6

the mean is 6.

Please helpppp!!!!!! It's 6th-grade thermal energy science.

Answers

Answer:

b?

Explanation:

The answer is C: Radiant energy from the sun travels through the glass, is absorbed by the black pot, and reflected by the aluminum foil.

If the reaction yield is 88.2%,what mass in grams of hydrogen is produced by the reaction of 7.73 g of magnesium with 1.31 g of water
Mg + 2h2o >>mg(oh)2+h2

Answers

Answer:

Mass of hydrogen produced is 0.07g.

Explanation:

Given data:

Mass of magnesium = 7.73 g

Mass of water = 1.31 g

Reaction yield = 88.2%

Mass of hydrogen produced = ?

Solution:

Chemical equation:

Mg + 2H₂O     →   Mg(OH)₂ + H₂

Number of moles of water:

Number of moles = mass/ molar mass

Number of moles = 1.31 g / 18 g/mol

Number of moles = 0.07 mol

Number of moles of magnesium:

Number of moles = mass/ molar mass

Number of moles = 7.73 g / 18 g/mol

Number of moles = 0.43 mol

Now we will compare the moles of water and magnesium with hydrogen.

                    Mg            :           H₂

                     1               :            1

                    0.43          :          0.43

                    H₂O          :             H₂

                      2             :              1

                   0.07           :            1/2×0.07 = 0.035

Mass of hydrogen:

Mass = number of moles × molar mass

Mass = 0.035 mol × 2 g/mol

Mass = 0.07  g

Answer: 0.064 grams is the answer

Explanation:

at the end you must multiply 88.2/100*0.073=0.064

Which of the following substances will dissolve in water? Check all that apply.
Magnesium Sulfate
Methane
Butane
Sodium nitrate​

Answers

Answer:

The answers are A. and D.

According to the concept of solubility and properties of ionic compounds, magnesium sulfate and sodium nitrate dissolve in water.

What is solubility?

Solubility is defined as the ability of a substance which is basically solute to form a solution with another substance. There is an extent to which a substance is soluble in a particular solvent. This is generally measured as the concentration of a solute present in a saturated solution.

The solubility mainly depends on the composition of solute and solvent ,its pH and presence of other dissolved substance. It is also dependent on temperature and pressure which is maintained.Concept of solubility is not valid for chemical reactions which are irreversible. The dependency of solubility on various factors is due to interactions between the particles, molecule or ions.

Learn more about solubility,here:

https://brainly.com/question/3479494

#SPJ2

The following is a list of common errors encountered in research laboratories. Categorize each as a determinate or an indeterminate error, and further categorize determinate errors as instrumental, operative, or methodic:
(a) An unknown being weighed is hygroscopic.
(b) One component of a mixture being analyzed quantitatively by gas chromatography reacts with the column packing.
(c) The tip of the pipet used in the analysis is broken.
(d) In measuring the same peak heights of a chromatogram, two technicians each report different heights.

Answers

Answer:

An unknown being weighed is hygroscopic. - operative error

One component of a mixture being analyzed quantitatively by gas chromatography reacts with the column packing. - methodic error

The tip of the pipet used in the analysis is broken. - instrumental error

In measuring the same peak heights of a chromatogram, two technicians each report different heights - operative error

Explanation:

In chemical analysis, operative errors are that largely introduced into the measurement because of variation of personal judgements of analysts. It is also a personal error that emanates solely due to the analyst.

A methodic error arises as a result of adopting defective experimental methods. For example, a column packing that reacts with a component of the mixture is used in the gas chromatography.

Instrument error refers to the error of a measuring instrument, for instance, the use of a pipette with a broken tip.

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