PERIODIC TABLE TEST WILL GIVE BRAINLIEST!
Helium is a gas found in the earth.

A.True

B.False

Neon is a gas from the earth. *


A.True

B.False

Elements are pure substances. *

A.True

B.False

Families/Groups on The Periodic Table go in this direction. *

A.vertical

B.horizontal

Rows which are called _______ run horizontal on The Periodic Table. *

A.pecans

B.periods

C.perfect

Click all that apply. Matter is found in ____________. *

A.clothing

B.humans

C.plants

D.cars

The worlds most accurate clock is a _____________. *

A.Timex

B.Rolex

C.Atomic

Humans are made of 99% elements. *

A.True

B.False

A grain of sand is the same size as one atom. *

A.true

B.false

The Periodic Table has _______ elements. *

A.112

B.116

C.96

​

Answer:

6.5

Explanation:

Answer:

No it is not balanced

Explanation:

CaCl2 + 2NaHCO3 → CO2 + CaCO3 + H2O + 2NaCl

Hope this helps

Answer:a a atom

Explanation:

Answer:

a. carbon

b. atomic number

c. mass number

d. 6

e. 7

f. 8

pls mark as brainliest

Answer:

Neon

Mass Number Half-life Decay Mode

Electron Capture

Electron Capture with delayed Proton Emission

18 1.6670 seconds Electron Capture

19 17.22 seconds Electron Capture

Answer:

Explanation:

The new volume can be found by using the formula for Boyle's law which is

[tex]P_1V_1 = P_2V_2[/tex]

where

P1 is the initial pressure

P2 is the final pressure

V1 is the initial volume

V2 is the final volume

Since we are finding the new volume

[tex]V_2 = \frac{P_1V_1}{P_2} \\[/tex]

So we have

[tex]V_2 = \frac{5 \times 40}{1} \\ = 5 \times 40[/tex]

We have the final answer as

Hope this helps you

Answer:

HNO₂ ⇄ H⁺ + NO₂⁻

Ka = 4.0 × 10⁻⁴

Explanation:

Step 1: Given data

Step 2: Write the acid dissociation reaction

Nitrous acid is a weak acid that dissociates according to the following expression.

HNO₂ ⇄ H⁺ + NO₂⁻

Step 3: Calculate the concentration of H⁺

We will use the definition of pH.

pH = -log [H⁺]

[H⁺] = antilog - pH = antilog -2.70 = 2.00 × 10⁻³ M

Step 4: Calculate the acid dissociation constant (Ka)

For a weak acid, we can calculate Ka using the following expression.

Ka = [H⁺]²/Ca

Ka = (2.00 × 10⁻³)²/0.010

Ka = 4.0 × 10⁻⁴

Answer:

Explanation:

Sr(OH)₂.+ 2HCl = SrCl₂ + 2H₂O

Moles of HCl in 28mL of .10 M HCl = .028 x .1 = .0028 moles .

Moles of Sr(OH)₂ in 60mL of .10 M Sr(OH)₂ = .060 x .1 = .0060 moles

2 moles of HCl  reacts with 1 mole of Sr(OH)₂

.0028 moles of HCl  reacts with .0014  mole of Sr(OH)₂

moles of Sr(OH)₂ remaining = .0060 - .0014 = .0046 moles .

Sr(OH)₂  = Sr⁺  +  2OH⁻

1 mole                  2 mole

.0046                    .0092

Total volume of solution = 88 mL .

88 mL of solution contains .0092 moles of OH⁻

concentration of OH⁻ = .0092 / .088

= .1045 M  .

When Strontium hydroxide, Sr(OH)₂ will react with hydrochloric acid (HCl) then the reaction formed will be:

Sr(OH)₂+ 2 HCl ⇒ SrCl₂ + 2 H₂O

The concentration of OH in the resulting solution will be 0.1045 M.

This can be calculated by:

[tex]\text{Molarity} = \dfrac{\text{moles}}{\text{volume of the solution in litres}}[/tex]

Moles of HCl = 0.028 x 0.1 = 0.0028 moles

Moles of Sr(OH)₂ =  0.060 x 0.1 = 0.0060 moles

Remaining moles of Sr(OH)₂  = 0.0060 - 0.0014 = 0.0046 moles

Sr(OH)₂   ⇒   Sr⁺ + 2OH⁻

1 mole                    2 mole

0.0046                  0.0092

Total volume of solution = 88 mL

88 mL of solution contains 0.0092 moles of OH⁻

Hence, concentration of OH⁻ :

[tex]= \dfrac{0.0092 }{0.088}[/tex]

= 0.1045 M

Therefore, 0.1045 M will be the concentration of OH in the solution.

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Answer:

123.1L

Explanation:

Given parameters:

Molarity of Cu(NO₃)₂  = 0.650M

Mass of  Cu(NO₃)₂ = 15g

Unknown:

Volume of  Cu(NO₃)₂ = ?

Solution:

To solve this problem, we have to first find the number of moles of the given mass;

  Number of moles of Cu(NO₃)₂  = [tex]\frac{mass}{molar mass}[/tex]

   Molar mass of Cu(NO₃)₂  = 63.5 + 2 (14 + 3(16)) = 187.5g/mol

 Number of moles of Cu(NO₃)₂  = [tex]\frac{15}{187.5}[/tex]  = 0.08 mol

Molarity is given as;

  Molarity  = [tex]\frac{number of moles }{volume}[/tex]  

         Volume  = [tex]\frac{number of moles }{molarity }[/tex]  

  Insert the parameters and solve;

        Volume  = [tex]\frac{0.08}{0.65}[/tex]  = 0.12L

Now mL;

         1L  = 1000mL

        0.12L will give 1000 x 0.12  = 123.1L

The lithium ion[Li⁺]=1.642 M

Ionic compounds will dissociate into ions when dissolved in water. The strength of the dissociation depends on the strength of the electrolyte properties. The stronger it is, the more ions will dissociate

Reaction

Li₂S⇒2Li⁺+S²⁻

mol ratio Li₂S : Li⁺: S²⁻ = 1 : 2 : 1

so the lithium-ion (Li⁺) concentration :

[tex]\tt 2\times 0.821=1.642~M[/tex]

Answer:

A

Explanation:

Why not

Answer:

A on edge 2021

Explanation:

0.8 L

We are given:

Molarity of Ethanoic Acid in vinegar = 0.125 M

Number of moles of Ethanoic Acid = 0.1 mole

Finding the volume of the solution:

We know that the molarity of a solution is defined as:

Molarity = n / V   (where n is the number of moles and V is the volume in L)

replacing the variables with the given values:

0.125 = 0.1 / V

Multiplying by V on both the sides

0.125V = 0.1

Dividing both sides by 0.125

V = 0.1 / 0.125

V = 0.8 L

Therefore, the volume of the solution is 0.8 L

Answer:

The reactant in a chemical reaction that limits the amount of product that can be formed. The reaction will stop when all of the limiting reactant is consumed. Excess Reactant - The reactant in a chemical reaction that remains when a reaction stops when the limiting reactant is completely consumed.

Explanation:

Answer:

be.77.0kj.

Explanation:

add moles then times

Considering the definition of enthalpy of vaporization,  the correct answer is option c. the heat required to vaporize 15.8 g of CH₃OH at its boiling point is 18.8 kJ.

When a material changes phase from solid to liquid, or from liquid to gas, a certain amount of energy is involved in this phase change.

In case of phase change from liquid to gas, this amount of energy is known as enthalpy of vaporization (symbolized as ∆H vap), also known as (latent) heat of vaporization or heat of evaporation.

In other words, the enthalpy of vaporization is the amount of energy required to change a unit of mass (for example, moles or kg) of a substance from phase liquid to phase gas at constant temperature and pressure.

In this case, you know that enthalpy of vaporization is ∆Hvap = 38.0 kJ/mol.

On the other side, you want to vaporize 15.8 g of CH₃OH.  Then, being the molar mass of the compound 32 g / mole (that is, the amount of mass contained in one mole), the number of moles to be vaporized is:

[tex]15.8 gramsx\frac{1 mol}{32 grams}= 0.49375 moles[/tex]

Then, the heat required to vaporize 0.49375 moles of CH₃OH at its boiling point is calculated taking into account the enthalpy of vaporization by:

0.49375 moles×  38.0 kJ/mol= 18.76 kJ ≅ 18.8 kJ

Finally, the correct answer is option c. the heat required to vaporize 15.8 g of CH₃OH at its boiling point is 18.8 kJ.

Learn more:

Answer:

Not sure if you just wanted the basic structure or full on structure.

Explanation:

When rocks are subjected to high heat, high pressure, hot mineral-rich fluids, or, more typically, some combination of these variables, metamorphic rocks develop.

Rocks are defined as those formed from magma, a molten mixture of rock-forming minerals and typically volatiles such as gases and steam.

There are three types of rocks.

Thus, when  rocks are subjected to high heat, high pressure, hot mineral-rich fluids, or, more typically, some combination of these variables, metamorphic rocks develop.

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Answer:

CH3 – CH – CH – CH2 – CH – CH3

| | |

CH3 CH2 CH3

|

CH3

Explanation:

3 - etil - 2, 5 - dimetilhexano

Answer:

Explanation:

First divide 25.0 by 6.5 to get the amount of fuel you have.  

Answer:

6moles of Li : 1 mole of N₂

Explanation:

The reaction equation is given as:

        6Li   +   N₂  →   2Li₃N

Mole ratio of Li to N₂;

From the balanced reaction equation:

    6 moles of Li will react with 1 mole of N₂;

The mole ratio is:

      6moles of Li : 1 mole of N₂

Answer:

Based on what you have seen in the Doppler Effect Gizmo, what is the best definition of the Doppler effect? A change in the frequency of a wave caused by the motion of the source relative to the observer. The increase in volume of a sound as the source approaches an observer.

Explanation:

Answer:

72

Explanation:

The pattern here may be hard to find at first, but it's this: the number in the middle of the triangle = (number at lower left corner of triangle x number at upper vertex of triangle) + (number at upper vertex of triangle x number at lower right corner of triangle).

Thus, for the missing value...

Missing value = (3x8) + (8x6) = 24+48 = 72.

Could you tell me what concept in chemistry relates to this? I'm interested.

Also check out stylesben's answer. Seems like there's several ways of doing this.

Answer:

the answer is 72

Explanation:

6+3=9 and multiply 9 with 8 and answer comes 72

the answer is electrons.....

Answer:

electrons

Explanation:

Answer:

I am the one who you just got a 100 points from from the 100 Point giveaway. I guess I gave away all my points except for one, so I need more points so I hope you don't mind if I am writing this, because you won't get another person to answer. Sorry!

Explanation:

Answer:

The answer to your question is given below

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

Zn + 2HCl —> ZnCl2 + H2

Thus, we can write out the atoms present in both the reactant and the product by doing a simple head count. The atoms present are listed below:

Element >>> Reactant >>> Product

Zn >>>>>>>> 1 >>>>>>>>>> 1

H >>>>>>>>> 2 >>>>>>>>> 2

Cl >>>>>>>>> 2 >>>>>>>>> 2

Answer:

answer is d Combining

Explanation:

I did the test and got it correct

As a chemical change takes place when binders are added to a paint mixture combining part of the manufacturing process occurs.

Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.

There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.

There are three types of chemical changes:

1) inorganic changes

2)organic changes

3) biochemical changes

During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.

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Answer:

D, Lions

Explanation:

Lions are meat eaters, meaning their food and energy requirements derive solely from anima tissue or meat (whether from hunting or scavenging)

The diagram is correct because electrons are present in distinct energy levels around the nucleus. Option D

Let nus just take a minute to be able to remind ourselves that when we look at the atom that there are several subatomic particles that can be shown to be able to make up the atom. We know that the electron is the particle that can be shown to be arranged in shells.

What we saw in the inner or the core of the atom is the nucleus and the six grey spheres  that we can see there would have to do with the nucleus of the atom that is in the question.

As we now look up at the shells, we can see the electrons as they have been arranged into the respective shells were they can be found in the atom on the basis of the energy that they possess.

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Answer:

The resulting solution is basic.

Explanation:

The reaction that takes place is:

First we calculate the added moles of HNO₃ and KOH:

As there are more KOH moles than HNO₃, the resulting solution is basic.

The resulting solution is basic.

• It is known that KOH is a base and HNO3 is an acid, so when they mix they undergo a neutralization reaction.  

• The reaction between there will be,  

HNO3 + KOH ⇔ KNO3 + H2O

Based on the given information,

• The volume of HNO3 is 12.5 ml and the molarity is 0.280 M, and the volume of KOH is 5 ml and the molarity is 0.920 M.

Now 1 mole of HNO3 completely reacts with 1 mole of KOH,

The millimoles of HNO3 is,

[tex]= Molarity * Volume (in ml)\\= 0.280 * 12.5\\= 3.5 mmol[/tex]

The millimoles of KOH is,

[tex]= Molarity * Volume (in ml)\\= 0.920 * 5.0\\= 4.6 mmol[/tex]

Now it can be seen that 3.5 millimoles of HNO3 completely reacts with 3.5 millimoles of KOH. Now we are left with 4.6-3.5 = 1.1 mmol of KOH.

Thus, KOH is in excess amount present in the solution, and as it is basic in nature, therefore, the resultant solution would be basic in nature.

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