What is the atomic number?
pls help.

What Is The Atomic Number?pls Help.

Answers

Answer 1

Answer:

8

Explanation:


Related Questions

How do the valence electrons of an element determine how they will combine with other elements to produce a compound? Please help this is urgent :)

Answers

Answer:

See explanation

Explanation:

The valence electrons are electrons found on the valence (outermost) shell of an atom.

When an atoms form compounds, there is an exchange of valence electrons between the atoms of one element and the atoms of another element.

Let us consider a typical example, sodium has one valence electron and chlorine has seven valence electrons. This means that chlorine needs one electron to complete its octet while sodium needs to release one electron in order to attain the octet structure.

So, sodium gives out its one electron and becomes a stable sodium ion and chlorine accepts that electron and becomes a stable chloride ion. This is how the compound sodium chloride is formed.

The students used 90.0 g/mol as the molar mass of oxalic acid. Use this value to determine how the students calculated the number of moles of oxalic acid present that were completely neutralized by the base.

Answers

Answer:

Hi there, the question asked is not complete but not to worry, I will give an explanation that you will be able to solve similar question or the same question when you get the whole question.

Explanation:

Oxalic acid is a diprotic acid and the acid is used with or react with sodium Hydroxide, NaOH in order to determine the molar mass of unknown diprotic acid. Oxalic Acid reacts with sodium as it is given in the balanced chemical reaction below:

(COOH)₂ + 2NaOH ------------------------------------------------------> Na₂C₂O₄ + 2H₂O.

The amount of the oxalic needed is known, say x gram and the molar mass is known. Thus, the number of moles of the oxalic acid= mass/molar mass = x gram/ 90.0 g/mol.

So we say that (COOH)₂ is a primary standard acid which is been used to standardize the base that is Sodium hydroxide.

Then, if we have an unknown diprotic acid, say H₂A, we can react it with NaOH to get the molar mass of the unknown.

H₂A + 2NaOH ---------------------------------------------------------------> Na₂A + 2H₂O.

Therefore, the number of moles of the acid = [concentration of NaOH × volume of NaOH] × [ 1 mole of the acid/ 2 mole of NaOH].

Riboflavin is one of the B vitamins It is also known as B6 and is made up of carbon, hydrogen, nitrogen and oxygen atoms. When 10.0 g of vitamin B6 is burned in oxygen, 19.88 g of CO2 and 4.79 g of H2O are obtained. Another experiment shows that vitamin B6 is made up of 14.89% of N. What is the simplest formula for vitamin B6

Answers

Answer:

C₁₇H₂₀N₄O₆

Explanation:

First, we need to determine the percentage of the atoms in the molecule. Then, assuming a basis of 100 we must convert the mass of each atom to moles. Simplest formula is the simplest ratio of atoms presents in the molecule:

%C:

19.88g CO2 * (12.01g/mol C / 44.01g/mol CO2) = 5.425g C

5.425g C / 10.0g * 100 = 54.25% C

%H:

4.79g H2O * (2*1.01g/mol / 18.015g/mol) = 0.537g H

0.537g H / 10.0g * 100 = 5.37%

%N:

14.89%

%O:

100 - 14.89% - 54.25% - 5.37% = 25.49%

Moles of each atom in a basis of 100g:

C: 54.25g * (1mol / 12.01g) = 4.517moles

H: 5.37g * (1mol / 1.01g) = 5.317 moles

N: 14.89g * (1mol / 14.01g) = 1.063 moles

O: 25.49g * (1mol / 16g) = 1.593 moles

Dividing each amount of moles in the lower number of moles (moles N):

C = 4.517mol / 1.063mol = 4.25

H = 5.317mol / 1.063mol = 5

N = 1.063mol / 1.063mol = 1

O = 1.593mol / 1.063mol = 1.5

This ratio multiplied 4 times to obtain whole-numbers:

C = 4.25*4 = 17

H = 5*4 = 20

N = 1*4 = 4

O = 1.5*4 = 6

The simplest formula for vitamin B6 is:

C₁₇H₂₀N₄O₆

What are sources of electricity? List as many as you can

Plz Help me plz

Answers

Answer:

Solar energy, wind energy, biomass energy.

Explanation:

What is the mass of 3.00 -1023 particles of water? Water has a molar mass of 18.0 g/mol.
3.00 grams
18.0 grams
6.00 grams
9.00 grams

Answers

Answer:

bro

Explanation:

guhfuyfouyvyu

Answer:

9.00

Explanation:

I took the test and got it correct ...

In which way are photosynthesis and cellular respiration different?
Cellular respiration produces oxygen, while photosynthesis uses oxygen.
Cellular respiration is endothermic, while photosynthesis is exothermic.
Photosynthesis uses carbon dioxide, while cellular respiration produces carbon dioxide
Photosynthesis releases energy, while cellular respiration stores energy.

Answers

Answer: Photosynthesis uses carbon dioxide, while cellular respiration produces carbon dioxide.

Explanation: i took the test lol

BALANCE THIS CHEMICAL EQUATION PLS, help:)

Answers

Answer:

4C₈H₄OH +  35O₂  →  32CO₂   +   10H₂O  

Explanation:

The unbalanced reaction expression is given as:

     

         C₈H₄OH +  O₂  →  CO₂   +   H₂O  

To solve this problem, we use a mathematical approach.

     aC₈H₄OH +  bO₂  →  cCO₂   +   dH₂O

Conserving C: 8a  = c

                    H:  5a  = 2d

                    O: a + 2b  = 2c + d

Let a  = 1, c  = 8, d  = [tex]\frac{5}{2}[/tex]  , b  = 35

   4C₈H₄OH +  35O₂  →  32CO₂   +   10H₂O  

   

0.8 gram of divalent metal was dissolved in 100 CC of 1.28 N HCl and the solution was diluted to to 200 cc. then 50cc of this solution required 54.6 CC of 0.22N NaOH for the neutralization. find the atomic weight of metal .​

Answers

Answer:

80g/mol is the molar mass of the metal

Explanation:

A divalent metal M reacts with HCl as follows:

M + 2HCl → MCl₂ + H₂

The excess of HCl is titrated with NaOH. Thus, we can solve the moles of HCl that reacts with the metal and the moles of the metal. As the atomic weight is the ratio between the mass and moles of the atom:

Moles NaOH:

0.0546L * (0.22mol / L) = 0.0120 moles NaOH = Moles HCl in excess

For NaOH and HCl solutions, Normality is the same than molarity.

Moles HCl added:

0.100L * (1.28mol / L) = 0.128 moles HCl * (50mL / 200mL) = 0.032 moles

Moles HCl in that react:

0.032 moles - 0.012 moles = 0.020 moles HCl

Moles M:

0.020 moles HCl * (1mol M / 2 mol HCl) = 0.010 moles M

Molar mass M:

0.8g / 0.010mol =

80g/mol is the molar mass of the metal

A copper wire is 44.85 cm long and weighs 1.521 g. The density of copper is 8.933 g/cm3.

What is the radius of the wire in millimeters?
What is the diameter of the wire?

Answers

Answer:

i am so sorry

Explanation:

The density of copper is  If a sample 8.933 g/cm3. If copper has a volume of 12.993 cm^3. Then the mass will be 136.29 gram.

How can we calculate the mass from density and volume?

Density is defined as the mass per unit volume it means that mass present in 1 meter cube is called density. The S.I unit of density is kg/m^3 and in C.G.S it is gram/cm^3

So, In above question can understand that density, mass, and volume all are convert to each other it means that if we know any two variable then third one will be calculated easily.

Mathematically,

Formula for density will be as mentioned below:-

Density = Mass/Volume.

From above formula we can calculate mass which is as follows:-

Mass = Volume × Density.

S.I unit of mass is kilograms and C.G.S unit is gram.

So In above question

Density = 8.933 gram/cm^3

Volume = 12.993 cm^3

So from above formula

Mass = Density × volume

          = 10.49 × 12.993

          = 136.29 gram

          = 0.13629 kilogram

So Mass is equal to 136.29 gram or 0.136 kilograms.

Therefore,The density of copper is  If a sample 8.933 g/cm3. If copper has a volume of 12.993 cm^3. Then the mass will be 136.29 gram.

Learn more about density here:

https://brainly.com/question/15164682

#SPJ2

Which of the following chemical equations correctly
represents between calcium hydroxide and
hydrochloric acid?
+ 2HCI →
CaCl2(aq) + 2H20)
'(aq)
+ HCI →
'(aq)
A Ca(OH)2(aq)
B Ca(OH)2(aq)
C Ca(OH)2(aq)
D Ca(OH)2(aq)
O
caCl(aq)
CaCl2(aq)
+ H2O
+ 2H200
+ HCl(aq)
+ 2HCI
'(aq)
Caci,
2(aq)
+ 2H211)
+
2(g)

Answers

Answer:

Ca(OH)2 + HCI

Explanation:

Calcium hydroxides formula is: Ca(OH)2

Hydrochloric Acids formula is : HCI

Please rate and give thanks!

What is another name for infrared energy? Choose all that apply.

Question 1 options:

Microwave energy


Visible light


Thermal energy


Heat

Answers

Answer: not 100% but maybe Visable Light...sorry if thats wrong

Explanation:

Thermal energy is the another name for infrared energy.

What is infrared radiation?

Infrared radiation is a type of radiant energy that is  not visible to human eyes but we can feel as heat energy.

Infrared radiation (IR), also known as thermal radiation. It is that band of energy in the electromagnetic radiation spectrum with wavelengths between 780 nm and 1 mm so we can conclude that thermal energy is the another name for infrared energy.

Learn more about radiation here: https://brainly.com/question/24524460

How many formula units are contained in 0.57 g Cao?

Answers

Then you will multiply the number of moles by 6.022×1023formula units/mol . To determine the molar mass of a compound, add the atomic weight on the periodic table in g/mol times each element's subscript. Since the formula unit CaO has no subscripts, they are understood to be 1

What is the charge is the ion when lithium reacts with chlorine

Answers

When lithium reacts to chlorine it goes from having no charge to +1 charge, while chlorine goes from neutral to having -1 charge.

How many moles of hydrogen react with 4.5 moles of oxygen to synthesize water?

Answers

Answer:

9moles of hydrogen gas

Explanation:

To solve this problem, we write the reaction expression first;

                       2H₂   +   O₂    →     2H₂O

We have been given the number of moles of oxygen gas to be:

 Number of moles of oxygen gas  = 4.5moles

From the balanced reaction expression:

      1 mole of oxygen gas reacts with 2 moles of hydrogen gas

  4.5moles of oxygen gas will react with 4.5 x 2  = 9moles of hydrogen gas

Vinegar is insoluble in vegatable oil. Does this mean that vinegar is a totally insoluble substance?

Answers

No, vinegar can be soluble in water since water is the universal solvent

Answer:

No

Explanation:

This does not mean that vinegar is insoluble totally. In fact, vinegar is soluble in water because water is a polar solvent.

For a substance to be soluble in another, it must obey the rule of solubility.

The rule states that "like dissolves like"

It implies that polar solvent will only dissolve polar solute.

Also, non-polar solvent will only dissolve non-polar solute.

Vegetable oil is a non-polar solventIt cannot dissolve a polar solute such as vinegar

Therefore, the answer is no, vinegar will dissolve in water.

table salt conducts electricity in water, but sugar does not. Explain why?

Answers

Answer:

Because sugar has no ions in the solution

Explanation:

Pure water contains very few ions, so it does not conduct electricity very well. When table salt is dissolved in water, the solution conducts very well, because the solution contains ions. When sugar is dissolved in water, the solution does not conduct electricity, because there are no ions in the solution.

In basic words the more ions in the solution there is a better chance to conduct electricity.

Question 2 of 10 A chemist has a block of copper metal (density is 8.96 g/mL). They drop the metal into a graduated cylinder containing water, and find the volume change is 2.90 mL. What is the mass of the block, in grams? h​

Answers

Answer:

m = 25.98 g

Explanation:

Given data:

Density of copper metal = 8.96 g/mL

Volume of copper metal block = 2.90 mL

Mass of copper metal block = ?

Solution:

The volume of given block of copper is equal to the volume change of water by adding this block.

Density formula:

d = m/v

by putting values,

8.96 g/mL = m/ 2.90 mL

m = 8.96 g/mL × 2.90 mL

m = 25.98 g

Does the model represent a chemical reaction? (Image)

Answers

Answer:

yes it is a chemical reaction

Explanation:

because the substances combined and made something new

Identify the Sun activity that travels from one sunspot to another sunspot.

Group of answer choices

Prominence

corona mass ejection

solar wind

solar flare

Answers

Answer:

solar flair I think I'm not sure

Please help ASAP
Read thing for the question thanks!!

Answers

Answer:

JOSHUA

Explanation:

JOSHUA

= 1
= 2
5
= 3
10
= 6
7
8
Write a balanced half-reaction for the reduction of gaseous oxygen (02) to liquid water
to liquid water (H2O) in acidic aqueous solution. Be sure to add physical state symbols
where appropriate.
a​

Answers

A balanced half-reaction :

O₂(g)+ 4H⁺(aq)+ 4e⁻⇒2H₂O(l)

Further explanation

Given

Reduction of gaseous oxygen (O₂) to liquid water(H₂O)

Required

A balanced half-reaction

Solution

Step 1 : Equalize the number of elements by adding coefficients

Equates element O

O₂(g)⇒2H₂O(l)

Step 2 : Equalize H by adding H⁺ on the opposite side (the deficient area of H).

O₂(g)+ 4H⁺(aq)⇒2H₂O(l)

Step 3 : Equalized the charge using the addition of electrons (e⁻) along the H⁺ field.

O₂(g)+ 4H⁺(aq)+ 4e⁻⇒2H₂O(l)

how many electrons are in an atom with the electron configuration of 1s22s22p63s1

Answers

Answer:

11

Explanation:

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

Electronic configuration => 1s²2s²2p⁶3s¹

Number of electrons =?

We must understand that the electronic configuration of an element is written based the number of electrons present in the atom of the element.

To obtain the number of electrons in the atom given in the question above, we simply add up the electrons in each orbital. This can be obtained as follow:

Electronic configuration => 1s²2s²2p⁶3s¹

Number of electrons =?

Number of electrons = 2 + 2 + 6 + 1

Number of electrons = 11

Thus , the number of electrons in the atom is 11

A purified protein is in a HEPES buffer at pH 7.0 with 600 mM NaCl. A 1 mL sample of the protein solution is dialyzed against 1.0 L of the same HEPES buffer with 0 mM NaCl. Once the dialysis has come to equilibrium, what is the concentration (in mM) of NaCl in the protein sample

Answers

Answer:

Explanation:

Using the dilution formula to determine the final concentration of NaCl in the protein sample.

[tex]M_1V_1 = M_2V_2[/tex]

[tex]600 \ mM \times 1 \ mL= M_2 \times ( 1000\ mL + 1 \ mL)[/tex]

[tex]M_2= \dfrac{600 \ mM \times 1 \ mL}{ ( 1001\ mL)}[/tex]

[tex]M_2= 0.599 \ mM[/tex]

However, when dialysis attains equilibrium, it implies that the sample was dialyzed twice, SO:

[tex]M_2 = \dfrac{600 \ mM\times 1 \ mL}{201 \ mL} = 2.97 \ mM[/tex]

Now, take the concentration as 2.97 mM

Then:

[tex]M_f = \dfrac{2.985 mM \times 1 mL}{201 \ mL}[/tex]

[tex]M_f = 0.01485 \ mM[/tex]

[NaCl] = 0.01485 mM

7. You are about to perform some intricate electrical studies on single skeletal muscle fibers from a gastronemius muscle. But first, you must prepare 6L of a 170 mM NaCl solution in which to bath the isolated muscle during your studies. How many grams of NaCl must you weigh out on the lab balance to prepare this bath solution

Answers

Answer:

58.61 grams

Explanation:

Taking The molecular weight of NaCl = 58.44 grams/mole

Determine how many grams of NaCl to prepare the bath solution

first we will calculate the moles of NaCl that is contained in 6L of 170 mM of NaCI solution

= ( 6 * 170 ) / 1000

= 1020 / 1000 = 1.020 moles

next

determine how many grams of NaCl

= moles of NaCl * molar mass of NaCl

= 1.020 * 58.44

= 58.61 grams

How many significant figures are in 3.20x10^2 g?

Answers

Answer:

3

Explanation:

For numbers with decimals, count the number after the decimal.

Identify the best practices when storing and using drying agents in the lab.
A. Close the drying agent container whenever it is not in active use.
B. Let the drying agent air out before removing it from the container.
C. Wrap the lid of the drying agent container with tape for storage.
D. Only use drying agent that appears clumpy in its original container.

Answers

Answer:

A. Close the drying agent container whenever it is not in active use.

C. Wrap the lid of the drying agent container with tape for storage.

Explanation:

Drying agents also known as desiccants are used in pharmaceutical, food and other manufacturing to keep substances dry. These drying agents are anhydrous and hygroscopic. The right usage of these products requires that they are always stored in an air-tight container.

When they are to be removed from a container containing a solvent, they are to be separated by filtration or decanting.

Calculate the following to the correct number of signifi- cant figures. Assume that all these numbers are measurements.
(a) x5 17.2 1 65.18 2 2.4
(b) x5 13.0217 17.10
(c) x5 (0.0061020)(2.0092)(1200.00)

Answers

Answer:

See below

Explanation:

First, you need to know what a significant figure means.

The significant figures in a measurement consist of all the certain digits in one measurement, including one uncertain or estimated digit.

With that being said, the second thing we need to do is to correct the exercise. According to an external source, the exercise is the following:

a) x = 17.2 + 65.18 - 2.4

In this case, we can say that 17.2 and 2.4 has the uncertain digit at the end, but in 65.18 it's the 8. Therefore, when we make the sum of all of this we have:

x = 17.2 + 65.18 - 2.4 = 79.98

The last digit is the uncertain digit, therefore, we won't include this digit. So the final result would have 3 significant figure. However 8 surpass 5, and hence, we should approximate our result. Then our final result is:

x = 80.0

b) x = 13.0217 / 17.10

The last digit of the 13, is the uncertain. So, doing this:

x = 13.0217 / 17.10 = 0.761502924

With the correct significant figure, this would be only 4 so:

x = 0.7615

c) x = (0.0061020)*(2.0092)*(1200.00)

Applying the same principle as before:

x = (0.0061020)*(2.0092)*(1200.00) = 14.712

Hope it helps

How many molecules are in 15 moles of CO2?

Answers

There are 90.345 x 10^23 molecules in 15 moles of CO2.

What is Avogadro's number?

Avogadro's number is the number of units, atoms or molecules in one mole of a substance which is equals to 6.02214076 × 1023. This number is also known as the Avogadro constant.

This means that one mole of a substance is equals to 6.02214076 × 1023 atoms, ions or molecules then 15 moles is equals to 90.345 x 10^23 molecules so we can conclude that there are 90.345 x 10^23 molecules are in 15 moles of CO2.

Learn more about mole here: brainly.com/question/1427235

model of reactants and model of products

H2CO3 → H2O + CO2

Answers

Answer:

Kindly check the picture attachment.

Explanation:

H2CO3 --------------------------> H2O + CO2

The reaction above is a decomposition reaction showing how the carbonic acid that is H2CO3 decomposed into H2O and CO2. The study of how reactants react(that is the amount in which they react) in order to form a product (and the amount of product formed) is known as the stoichiometry.

H2CO3 which is the reactant has three oxygen atoms which are all directly bonded to the carbon atom. One of the oxygen atom is bonded doubly to the carbon atom.

CO2 and H2O are the products. The CO2 is linear, O=C=O with the two oxygen atoms bonded doubly each to each carbon atoms. The H2O is bent.

Gather data: Four other pairs of elements in the same chemical family are listed below. List the number of valence electrons in each element. Beryllium Nitrogen Oxygen Fluorine Magnesium Phosphorus Sulfur Chlorine

Answers

Explanation:

Valence electrons is the number of electrons in the outermost shell of an atom. For the main group elements, the group number represents the number of valence electrons.

Beryllium

This belongs to the group 2 hence, it has valency of 2.

Nitrogen

This belongs to group 5, hence it has valency of 5.

Oxygen

This belongs to group 6, hence it has valency  of 6.

Fluorine

This belongs to group 7, hence it has valency of 7.

Magnesium

This belongs to group 2, hence it has valency of 2.

Phosphorus

This belongs to group 5, hence it has valency of 5

Sulphur

This belongs to group 6, it has valency of 6

Chlorine

This belongs to group 7, it has valency of 7

Answer:

Beryllium: 2 valence electrons.

Nitrogen: 5 valence electrons.

Oxygen: 6 valence electrons.

Fluorine : 7 valence electrons.

Magnesium : 2 valence electrons.

Phosphorus : 5 valence electrons.

Sulphur : 6 valence electrons.

Chlorine : 7 valence electrons.

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