please need asap
An atom with 38 protons and 49 neutrons would be



Strontium-49


Francium-49


Strontium-87


Francium-87

Answer:

B

Explanation:

Just did it on usa test prep

The element which is most likely to be magnesium  is the element with the electronic configuration same as magnesium.

It is defined as a substance which cannot be broken down further into any other substance. Each element is made up of its own type of atom. Due to this reason all elements are different from one another.

Elements can be classified as metals and non-metals. Metals are shiny and conduct electricity and are all solids at room temperature except mercury. Non-metals do not conduct electricity and are mostly gases at room temperature except carbon and sulfur.

The number of protons in the nucleus is the defining property of an element and is related to the atomic number.All atoms with same atomic number are atoms of same element.

Learn more about element,here:

https://brainly.com/question/14347616

#SPJ6

Answer:

42

Explanation:

Because the proton number or atomic number is equal to electron number.

Answer:

42

In order for it to be neutral there must be the same amount of protons and neutrons

Have a nice day!   :)

Answer:

V = 34.55 L

Explanation:

Given that,

No of moles, n = 1.4

Temperature, T = 20°C = 20 + 273 = 293 K

Pressure, P = 0.974 atm

We need to find the volume of the gas. It can be calculated using Ideal gas equation which is :

PV=nRT

R is gas constant, [tex]R=0.08206\ L-atm/mol-K[/tex]

Finding for V,

[tex]V=\dfrac{nRT}{P}\\\\V=\dfrac{1.4\times 0.08206\times 293}{0.974 }\\\\V=34.55\ L[/tex]

So, the volume of the gas is 34.55 L.

Answer:

A. Potential energy is stored energy

Explanation:

Answer:

A

Explanation:

i have the same question

Answer:

the volume will expand

Explanation:

gas under pressure contracts, and expands with a lesser pressure

The volume of the hydrogen gas at 25 kPa is 8 Liters.

Explanation:

Given:

At constant temperature, 2 liters of hydrogen gas at 100kPa pressure.

To find:

The volume of the hydrogen gas at 25kPa.

Solution:

The initial pressure of the hydrogen gas =[tex]P_1=100 kPa[/tex]

The initial volume of the hydrogen gas at 100 kPa =[tex]V_1=2 L[/tex]

The final pressure of the hydrogen gas =[tex]P_2=25 kPa[/tex]

The final volume of the hydrogen gas at 25kPa = [tex]V_2=?[/tex]

Using Boyles law:

[tex]P_1V_1=P_2V_2\\100kPa\times 2 L=25 kPa\times V_2\\V_2=\frac{100 kPa\times 2L}{25 kPa}=8L[/tex]

The volume of the hydrogen gas at 25 kPa is 8 Liters.

Learn more about Boyles law here:

brainly.com/question/12835309?referrer=searchResults

brainly.com/question/1437490?referrer=searchResults

Answer:

ocean temp

Explanation:

If air temperature decreases, then wave height will decrease and ocean temperature will also decrease, but not as much.

The water's temperature at the surface is known as the ocean surface temperature. Depending on the measuring technique, the term "surface" might signify anything from 1 millimeter to 20 meters below the sea's surface.

Due to changes in solar radiation and the physical characteristics of water, the temperature of ocean water fluctuates depending on location, both in terms of latitude and depth.

Water contracts and gets denser as it cools. The density of water is influenced by temperature and salinity, and as a result, water moves up or down through the ocean's strata and circulates as currents.

Thus, option B is correct.

To learn more about ocean temperature, follow the link;

https://brainly.com/question/12111508

#SPJ2

Answer:

Salt

Explanation:

It has all -

Answer:

Explanation:

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

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

So we have

[tex]density = \frac{25}{90} = \frac{5}{18} \\ = 0.277777...[/tex]

We have the final answer as

Hope this helps you

Alkanes are saturated hydrocarbons that have single bonds in chains

General formula for alkanes :

[tex]\tt \large{\bold{C_nH_{2n+2}}[/tex]

Hydrocarbon combustion reactions (specifically alkanes)

[tex]\large {\box {\bold{C_nH _ (_2_n _ + _ 2_) + \dfrac {3n + 1} {2} O_2 \Rightarrow nCO_2 + (n + 1) H_2O}}}[/tex]

So that the burning of ethane with air (oxygen):

[tex]\tt C_2H_6+\dfrac{7}{2}O_2\rightarrow 2CO_2+3H_2O[/tex]

2C₂H₆ (g) + 7O₂ (g) ⟶ 4CO₂ (g) + 6H₂O (ℓ)

or we can use mathematical equations to solve equilibrium chemical equations by giving the coefficients for each compound involved in the reaction

C₂H₆ (g) + aO₂ (g) ⟶ bCO₂ (g) + cH₂O (ℓ)

C : left 2, right b ⇒ b=2

H: left 6, right 2c⇒ 2c=6⇒ c= 3

O : left 2a, right 2b+c⇒ 2a=2b+c⇒2a=2.2+3⇒2a=7⇒a=7/2

Answer:

See explanation

Explanation:

The question is incomplete because the image of the alcohol is missing. However, I will try give you a general picture of the reaction known as hydroboration of alkenes.

This reaction occurs in two steps. In the first step, -BH2 and H add to the same face of the double bond (syn addition).

In the second step, alkaline hydrogen peroxide is added and the alcohol is formed.

Note that the BH2 and H adds to the two atoms of the double bond. The final product of the reaction appears as if water was added to the original alkene following an anti-Markovnikov mechanism.

Steric hindrance is known to play a major role in this reaction as good yield of the anti-Markovnikov like product is obtained with alkenes having one of the carbon atoms of the double bond significantly hindered.

Answer:

The block is made up of aluminum.

density = 2.7 g/cm³

Explanation:

Given data:

Dimension of metal block = 2.0 cm×2.5 cm× 3.0 cm

Mass of block = 40.05 g

Density of block = ?

Which metal is this = ?

Solution:

Density:

Density is equal to the mass of substance divided by its volume.

The symbol used for density is called rho. It is represented by ρ. However letter D can also be used to represent the density.

Units:

SI unit of density is Kg/m3.

Other units are given below,

g/cm3, g/mL , kg/L

Formula:

D=m/v

D= density

m=mass

V=volume

Volume of block = 2.0 cm×2.5 cm× 3.0 cm = 15 cm³

d = m/v

d = 40.5 g/ 15 cm³

d = 2.7 g/cm³

The block is made up of aluminum.

Explanation:

Mixtures can be separated using a variety of techniques. Chromatography involves solvent separation on a solid medium. Distillation takes advantage of differences in boiling points. Evaporation removes a liquid from a solution to leave a solid material.

Answer:

The increase in pressure of the reacting system will increase the formation of NH₃

Explanation:

The given parameters are;

2NH₃ (g) ⇄ N₂ (g) + 3H₂ (g)

The number of molecules in the reactant side of the equation = 2 molecules

The number of molecules in the product side of the equation = 1 + 3 = 4 molecules

Avogadro's law states that equal volume of all gases at a given temperature and pressure contains equal number of molecules

Therefore, given that the number of molecules of the product are twice the number of molecules of the reactant, the volume of the product is twice the volume of the reactant

If the pressure is increased, at constant temperature by Boyles law, the volume will be reduced, favoring the formation of the low volume occupying NH₃

Therefore, the reverse reaction (formation of NH₃) will preferably occur.

Answer:

The answer is B

Explanation:

The other answer is incorrect. The correct Answer is B

Trust Me

Answer: Yes.

Explanation:

the number of protons in the nucleus determines an element's identity. Chemical changes do not affect the nucleus, so chemical changes cannot change one type of atom into another. The number of protons in a nucleus does change sometimes, however. The identity of the atom, therefore, changes.

Answer:

1. 1g/ml

Explanation:

1. Density is mass divided by volume (g/mL).

10g/10mL = 1 g/mL

2. When you already know the density and the volume, you can use the density as a unit converter.

[tex]5mL*\frac{20g}{mL} = 100g[/tex]

3. It's the same with density and mass.

[tex]20g*\frac{1mL}{5g} = 4mL[/tex]

Answer:

This is a synthesis reaction.

Explanation:

Two elements are bonded together to form (synthesize) a new compound.

The density of the wood : 1.45 g/cm³

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  

[tex]\tt V=2.7\times 5.5\times 3.9=57.915~cm^3[/tex]

[tex]\tt \rho=\dfrac{m}{V}\\\\\rho=\dfrac{84~g}{57.915~cm^3}=\boxed{\bold{1.45`g/cm^3}}[/tex]

Answer:

c. .....................

Answer: the amount of carbon dioxide put into the atmosphere due to your consumption of fossil fuels

Your carbon footprint is the amount of carbon dioxide and other carbon compounds emitted, because of your use of fossil fuels.

Hope this helps!

Answer:

1.1 x [tex]10^{9}[/tex] km/h

Explanation:

Here we need to do two conversions- one from centimetres to kilometres and one from seconds to hours.

To get from cm to km- we divide by 100 000 since there are 100 000 cm in a km.

To get from seconds to hours we divide by 3600 since there are 3600 seconds in an hour

[tex]\frac{3*10^{10}cm/100000 }{1second/3600} =1.1*10^{9} km/h[/tex]

Answer:

The further away electrons are from the nucleus the easier it is for atoms to use electrons.

Explanation:

Answer:

Love it because Love it

Explanation:

Answer:

10

Explanation:

Khan Academy

Answer:

it's the first one

Explanation:

can you help me too

Answer:

easier and pollution

Explanation:

I just had this question and got it right

Answer: 2miles

Explanation:if he’s going 12 miles in one hour, in half an hour he would’ve made it 6 miles. 8-6=2

Answer: b. 2 miles

Explanation:

Answer:

Explanation:

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

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

From the question

mass = 30.5 g

volume = 2.2 cm³

We have

[tex]density = \frac{30.5}{2.2} \\ = 13.863...[/tex]

We have the final answer as

Hope this helps you

Answer:

2Mg+[tex]O_{2}[/tex]→2MgO

Explanation:

The first step is magnesium + oxygen equals magnesium oxide

The second step is changing that into an equation which looks like Mg+[tex]O_{2}[/tex]→MgO

The third step is to 2*Mg and 2*O as well as the product has to be 2*Mg,2*O which gets the equation to become balanced as 2Mg+[tex]O_{2}[/tex]→2MgO

The coefficient 2 balance the given reaction. The balanced equation for the given reaction is given as [tex]\rm Mg + O_2 \rightarrow 2MgO[/tex].

A balanced equation is a mathematical representation of a chemical reaction that respects the law of mass conservation. It depicts the reactants and products of the reaction, as well as the relative amounts of each species. The unbalanced equation is [tex]\rm Mg + O_2 \rightarrow MgO[/tex]. One magnesium (Mg) atom on the left side and one on the right side, so the magnesium is already balanced. Balance the oxygen (O) atoms. On the left side, there are two oxygen (O) atoms present in the O2 molecule. On the right side, there is only one oxygen (O) atom in the MgO molecule. To balance the oxygen atoms, we need to add a coefficient of 2 in front of MgO: [tex]\rm Mg + O_2 \rightarrow 2MgO[/tex]. The balanced equation is [tex]\rm Mg + O_2 \rightarrow 2MgO[/tex].

To know more about balanced equation, here:

https://brainly.com/question/12192253

#SPJ4

Answer:

1. Both metals and nonmetals are types of elements and can be involved in chemical reactions. Some of their differences are highlighted in the chart below.

  Metals:    

Appearance; Shiny.    

Conduct heat or electricity; Yes.  

Malleable or ductile; Yes, both and has great mechanical strength.    

Form stable compounds; Forms stable compounds with acids; also forms oxides; replaces hydrogen in acids or water; combine with nonmetals; often becomes positive.

  Nonmetals :  

Appearance; Not shiny .  

Conduct heat or electricity; Not well .  

Malleable or ductile; Brittle and not easily molded into shapes .  

Form stable compounds; Oxides usually give acid reactions in water; often becomes negative

2. The electrochemical series is an arrangement of metals in such order that any metal in the list is displaced from its compounds by any metal above it, but displaces any metal below it. The higher up the list a metal is, the greater its activity. Knowing a metal’s placement on this chart can help you understand the activity of the metal, especially in regard to its ability to displace hydrogen in acids. Any items on the list far above hydrogen will do a good job at displacing it, those near it won’t do such a good job, and those below it won’t displace it from acids at all.

3. When placed in water, acids dissociate and form free hydrogen ions, which determine the properties of acids. The number of hydrogen ions determines the strength of an acid. Strong acids dissociate to a large degree and produce a large number of hydrogen ions. Weak acids dissociate to only a slight degree.

When placed in water, bases dissociate and form free hydroxyl ions, which determine the properties of bases. Strong bases dissociate to a great degree and produce a large number of hydroxyl ions. Weak bases dissociate to only a slight degree.

When free hydrogen ions and free hydroxyl ions are removed from solutions of acids and bases, then the acidic and basic properties disappear. This is what happens when acids and bases are mixed together in proper proportion; the hydroxyl ion will unite with the hydrogen ion to form water. The resulting salt product is neutral.

4. Indicators are used to help determine the pH value of an unknown solution. These are often papers that turn a certain color at certain pH values.

Metals are good conductors of heat and electricity but the non-metals are not.

Metals are good conductors of electricity and heat whereas non-metals are poor conductors of heat and electricity. Metals have high density while on the other hand, non-metals have low density. Metals are malleable and ductile whereas non-metals are brittle.

So we can conclude that metals are good conductors of heat and electricity but the non-metals are not.

Learn more about metals here: https://brainly.com/question/4701542

#SPJ2