answer this step by step pls

Answers

Answer 1

Answer:

neutrons = mass number - atomic number

. = 39-19 =20

Related Questions

I WILL MARK BRAINLY-EST Do you think the way we perceive food in our culture supports the guidelines in MyPlate? Explain your

answer

Answers

Yes, some cultures eat healthier due to restrictions on some foods they won’t eat due to their culture. So eating healthier because of that endorses the guidelines on my plate since they push us to eat healthier. One prime example is Japanese culture they believe in a balanced meal and balanced presentation.

What mass of aluminium is needed to react with 640g of iron oxide

Answers

Answer:

13.5g

Explanation:

Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 138.8g of aluminium is needed to react with 640g of iron oxide.

What is mole?

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.

Mathematically, the balanced equation can be written as

3Fe[tex]_2[/tex]O[tex]_3[/tex] + 4Al [tex]\rightarrow[/tex] Al[tex]_2[/tex]O[tex]_3[/tex] + 6Fe

number of moles of iron oxide= 640/159.6

=4.01

number of moles of aluminium =(4/3)×4.01

=5.34moles

mass of aluminium =5.34×26

=138.8g

Therefore, 138.8g of aluminium is needed to react with 640g of iron oxide.

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the elements on the periodic table are arranged in order of increasing

Answers

Answer:

atomic number

Explanation:

A 16.0 L container at 333 K holds a mixture of two gases with a total pressure of 7 atm. If there are 2.72 mol of Gas A in the mixture, how many moles of Gas B are present?

Answers

A flower vase placed on the table

Explanation:

A laborer pushing a crate on the table

A 16.0 L container at 333 K holds a mixture of two gases with a total pressure of 7 atm. If there are 2.72 mol of Gas A in the mixture, no. of moles of Gas B are 1.376.

What is combined gas law?

The combined gas law is the law of of gaseous state which is made by combination of Boyle's law, Charle's law, Avogadro's law and Gay Lussac's law.

It is a mathematical expression that relates Pressure, Volume and Temperature.

(P1 × V1)÷T1 = (P2 × V2)÷T2

We can also use the following relation-

PV = nRT

Let n be the total no. of moles.

Given,

P = 7 atm

R = 0.0821

T = 333K

V = 16 L

n = PV / RT

n = 4.096

n = no. of moles of A gas + no. of moles of gas B

4.096 = 2.72 + x

x = 1.376

Therefore, A 16.0 L container at 333 K holds a mixture of two gases with a total pressure of 7 atm. If there are 2.72 mol of Gas A in the mixture, no. of moles of Gas B are 1.376.

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Samantha is investigating the densities of several liquids. Which action is the result of her creative thinking ?

Answers

Answer:

A. Poe

Explanation:

pagmali sorry na Lang

what is meant by pure substance????

Answers

Pure substance means substance is made of one type of molecules.Or you can tell it that the heterogeneous mixtures of molecules are called pure substances.For example:-Hydrogen,water ,all elements and compounds

How many molecules of H2O are there in 200,000,000L of gas at STP?

Answers

Mass of 1 mole of
H2O,200,000,000L,STP = 65.05999898g

Why was the creation of element 114 so special?

Answers

Answer:

It is classified as a metal and is expected to be solid at room temperature.

Explanation:

not sure but i guess it is that

Determine the rate of reaction at 50 C when the loss of mass is 0.95 g. Show your working. Give your answer to 2 significant figures.

* 20 points for who gets it *

Answers

This problem is providing information about the loss of mass for a reaction 50 °C as a function of the time elapse. Thus, when taking a look at the given graph, we can trace a horizontal line on the y-axis at 0.95 g in order to intercept it with the curve, and hence, figure out the time at which that loss of mass takes place.

Thus, we can see that when the loss of mass hits 0.95 g, the corresponding time on the graph is about 80 seconds, and hence, the rate of reaction turns out to be:

[tex]r=\frac{0.95g}{80s}\\\\r=0.012\frac{g}{s}[/tex]

Which has two significant figures as required.

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Which of the following statements about absolute zero is correct?

Answers

it is a 0 degrees on the Kelvin scale

it is also the lowest on the thermometer

also the particles stop moving and all disorder disappears.

How do the isotopes hydrogen-2 and hydrogen-3 differ?
A. Hydrogen-2 has three protons.
B. Hydrogen-2 has no protons.
C. Hydrogen-3 has one more electron than hydrogen -2.
D. Hydrogen-3 has two neutrons.
PLS SOMEONE HELP

Answers

Answer:

C hydrogen 3 has 0one more electron than hydrogen 2

A red car and a black car begin to accelerate from rest at the same time. The red car accelerates at a constant rate of 3 meters per square second. The motion of the black car is shown in the graph below.imageWhich of the following statements correctly compares the acceleration of the two cars?A.While the cars are accelerating, the red car accelerates faster than the black car.B.While the cars are accelerating, the black car accelerates faster than the red car.C.The red car only accelerates faster than the black car for the first second of acceleration.D.The black car only accelerates faster than the red car for the first second of acceleration.

Answers

That car moves or accelerates faster which has the higher speed.

If the red car accelerate at higher speed than black car then the red car reach first on the destination but if the black car moves with higher speed than red car then the black car reach its destination earlier than the red car.

The conclusion can be drawn when the image is present or any data but there is no data or image present which provides us accurate information so we can conclude logically that car which moves at higher speed will move faster than the other car.

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what does not happen when the temperature is increased ?

Answers

More particles collide in the correct orientation

I agree with the person above me, more particles do collide in the correct orientation and the particles collide more often and with more energy.

how to keep apples from browning without lemon juice?

Answers

Answer:

eat

Explanation:

eat the dang apples

___is a measure of the change in velocity of a

moving object.

THIS IS URGENT ! Please fill in the blank

Answers

Acceleration is a measure of the change in velocity of a moving object. :)

I am an alkali metal located in the third period of the periodic table. Who am I?

Answers

Answer:

Magnesium

Explanation:

It's an alkali metal and is in the third period on the period table. I'm sure

The alkaline earth metal found in period 3 of the periodic table is magnesium.The lightest structural metal is magnesium (Mg), an alkaline-earth metal from Group 2 (IIa) of the periodic table.

I am an alkali metal located in the third period of the periodic table. Who am I?

Six chemical elements in Group 1, the periodic table's leftmost column, make up the alkali metals.They are francium (F), cesium (Cs), rubidium (Rb), potassium (K), sodium (Na), and lithium (Li) (Fr). One of the chemical elements in the third row of the periodic table of the chemical elements is referred to as a period 3 element. Magnesium is regarded as a metal because it is a member of group2.Acid and metals react to produce salt and hydrogen gas.As a result, magnesium interacts with diluted hydrochloric acid to produce magnesium chloride (salt) and hydrogen gas. Magnesium is a silvery, light metal that makes up 2% of the Earth's crust but is not present in nature.Only in combination with other elements like carbon, calcium, and oxygen, as in the common mineral dolomite, could this versatile element naturally arise. Magnesium is a cofactor in more than 300 enzyme systems that affect a variety of biochemical processes in the body, including as protein synthesis, blood glucose control, blood pressure regulation, and muscle and nerve function [1-3].Magnesium is necessary for the oxidative phosphorylation, glycolysis, and generation of energy. Magnesium supports muscle and neuron function as well as energy synthesis in the body, among many other vital functions.Typically, low magnesium levels don't result in any symptoms.On the other hand, persistently low levels can raise your risk of osteoporosis, type 2 diabetes, high blood pressure, and heart disease. For the majority of individuals, daily doses under 350 mg are safe.The adverse effects of magnesium can include nausea, vomiting, diarrhea, and upset stomach in some people.Magnesium is POSSIBLY SAFE UNTIL TAKEN IN VERY HIGH AMOUNTS (more than 350 mg daily).

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How could you break down the compound calcium carbonate into the elements that make it up ?
A. by melting
B. by crushing
C. with filter
D. with chemical changes

Answers

Answer:

A. By melting

Explanation:

You can break it down by thermal decomposition which is basically melting it and thats because many metal carbonates can take part in thermal decomposition reactions.

¿Cuál es la partícula mas pequeña del átomo?

Answers

Answer:

Los quarks son ciertamente unas de las partículas más pequeñas del universo. Son elementales, indivisibles y no se pueden romper en piezas menores.

Explanation:

why do atmospheric carbon dioxide levels fluctuate during the year?

Answers

Answer: The amount of CO2 found in the atmosphere varies over the course of a year. Much of this variation happens because of the role of plants in the carbon cycle

A beaker contains an acidified copper sulphate solution.A copper plate and a carbon plate is connected to postive terminal to battery whereas carbon rod is connected to negative terminal of battery.What will you observe when an electric current is passed through this setup for a considerable time

Answers

The copper plate connected to positive terminal (anode) will decrease in size and wear away and the copper plate connected to negative terminal (cathode) will increase in size and thicken, the electrolysis will continue until the anode completely disappears

why are metals generally good conductors of electric current?

Answers

Answer:

(Hope this helps can I pls have brainlist (crown)☺️)

Explanation:

Because the atoms in metals form a matrix through which outside electrons may easily travel, metals are good conductors of electricity and heat. They generate a sea of electrons around the positive nuclei of the interacting metal ions, rather than circling their particular atoms.

The free flow of shared electrons can carry an electric current through a metal. Carbon atoms join with iron atoms to create bonds.

What is the difference between Eukaryote and Prokaryote cells?

Answers

A eukaryotic cell is what most cells categorise into like animal, plant cells and many more it is a memory bound organelle and the dna is enclosed within the nucleus whereas a prokaryotic cell includes bacteria and Protista where the only organelles it contains is ribosomes and the dna is not enclosed in a nucleus but free flowing
pls make me brainliest

Two containers of gas have the same volume, temperature and pressure. One container has a sample of oxygen gas having a mass of 3.95g. The other container has a gas with a mass of 2.99g. Determine the molar mass of the gas in the second container.

Answers

Answer:

24.3

Explanation:

O2 has a molar mass of 16 X 2 =32

the number of moles for O2 is the weight divided by the molar mass or, but since the two container have the same P,V, AND T they have the same number of moles since

PV =nRT

the weight of the gas in the second container divided by its molar mass =

0.123

2.99/? = 0.123

? = 2.99/o.123 = 24.3

A. An atom neutral (one with 0 extra charge)?

Answers

Answer:

Neutron is the correct answer.

The missing box would be the number and this is a form of decay.

please help mark brainliest

Answers

Answer:

alpha decay or particle

Explanation:

omg y'all pls so much help me!!!
1. H2SO4
2. MGNO3
their %

Answers

H2SO4
H: 1 x 2 = 2
S: 32 x 1 = 32
O: 16 x 4 = 64
98amu

H: 2/98 x 100 = 2%
S: 32/98 x 100 = 33%
O: 64/98 x 100 = 65%

MGNO3 (I think you meant Mg(NO3)2 aka Magnesium Nitrate. So this might be wrong because I did the version you sent instead of what I thought you might mean.)

Mg: 24 x 1 = 24
N: 14 x 1 = 14
O: 16 x 3 = 48
86amu

Mg: 24/86 x 100 = 28%
N: 14/86 x 100 = 16%
O: 48/86 x 100 = 56%

the diagram of paper chromatography

Answers

I hope that the attachment helps you..

The following balanced equation shows the formation of water. 2H2 O2 â†’ 2H2O How many moles of oxygen (O2) are required to react completely with 1. 67 mol H2? 0. 835 mol O2 1. 67 mol O2 3. 34 mol O2.

Answers

Answer:

CO2 carbon dioxide emissions

H20 mental breakdown

02 is form of a kind

answer is acid + alkaline equal to salt and water

What type of bond is between NaCL?

Answers

Answer:

Ionic Bonds

Explanation:

Ionic bonds usually occur between metal and nonmetal ions. For example, sodium (Na), a metal, and chloride (Cl), a nonmetal, form an ionic bond to make NaCl.

which temperature scale avoids negative temperatures

Answers

Answer:

See below:

Explanation:

Hello! My name is Galaxy and I will be helping you today. I hope you are having a nice day.

There are 3 main ways to measure temperatures, you have Celsius, Fahrenheit, and Kelvins.

Celsius and Fahrenheit are main ways to measure heat in non-scientific terms, althought they are used sometimes when needed.

Kelvins are used for Science as they are precise and can deal with temperatures that are super hot or super cold.

The lowest temperature in Kelvins is 0 degrees Kelvin, also known as Absolute Zero. There are no temperatures above that. So the answer to your question would be Kelvins.

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