True/False: There are about 400 known elements

Answers

Answer 1

Answer: false

Explanation:

there are no more then 112 known elements.

Answer 2

Answer:

false

Explanation:

their are only 118 element


Related Questions

Pls help!!!

Briefly describe how plasma TVs display colour.

Answers

When the electricity flows into a tube, gas atoms crash inside producing invisible ultraviolet rays. There is a white phosphor coating that turns the invisible rays into visible light. In a plasma tv the cells are like tiny cfls only coated in phonsophers that are rgb

a letter stating three things that need urgent fixing in your school



Answers

Answer and Explanation:

Computers ( The computers are very old and very slow, and we have to notice that almost everyone are using computers at the same time at the school, which makes it even harder for it to load up assignments. )The Rick Rolling ( Everyone keeps sending links to teachers and students saying that it is part of some assignment but then you have to listen to Rick Astley, they should really block these links. )The lockers ( The lockers are also very old and they are breaking down and rusting a lot from the moisture in the hallways. One of the lockers even broke down today!!! I hope they can fix this so no one else gets hit with a locker door. )

Hope this helps! ;)

which cycle results in death of the host cell
A.lytic cycle
B.lysogenic cycle
C.both

Answers

Answer:

A. lytic cycle is the correct answer

Based on what you have learned about currents, how do you think this mass of trash ends up in the Great Pacific Garbage Patch?
Looking at the map, what ideas do you have about why the trash is "trapped" in this location?

Answers

By currents which push the trash into the “great pacific garbage patch” and the currents never stop so they can’t get out of the circle
(Hope this helps)

Which of the following statements does not describe a physical property of chlorine?
O The color of chlorine gas is green.
O The density of chlorine gas at standard temperature and pressure is 3.17 g/L. OChlorine combines with sodium to form table salt.
O The freezing point of chlorine is -101°C.​

Answers

Answer:

the chlorine gas is green

Explanation:

the density of

The statement that does not give description of physical property of chlorine in the question is   (The color of chlorine gas is green)

A physical property can be regarded as characteristic of matter which is not associated along with a change of it's chemical composition.

Some physical properties of substance can include density, hardness as well as  color, melting and boiling points, or electrical conductivity.

The freezing point ( -101°C ) as well as the density ( 3.17 g/L.) of chlorine  as given in the question are all physical properties because it not considered as been associated with a change chlorine chemical composition.

Therefore, the first option A is correct.

Learn more at :https://brainly.com/question/18327661?referrer=searchResults

Consider the reaction and the rate law below.

2O3 → 302
R= k[03]2

What is the overall order of the reactants in this rate law?

A. 0
B. 1
C. 2
D. 3​

Answers

The overall order of the reactants in this rate law : 2

Further explanation

Given

Reaction

2O3 → 302

The rate law :

R= k[03]²

Required

The overall order

Solution

The overall order  : the sum of orders for each reactant

For A + B ---> C + D

r = k [A]ᵃ[B]ᵇ

The overall reaction order is m+n

So for the rate law of R= k[03]², the overall order = 2

Which of the following statements best explains how the first generation 20 points
lady beetle from the above model changed in the later generations? *
Lady Booties
蒙赖隊徽
Finn
Gameretlen
Later
Genovation
In the first generation, the beetles with the dark spotted trait had a better chance of
survival. The beetles changed their color to better adapt to their environment, and the
species evolved to have a lighter color.
In the first generation, the beetles with the dark spotted trait had a better chance of
survival. The trait mutated over time, causing the beetles with that trait to be darker,
and the species evolved to have a darker color.
In the first generation, the beetles with the dark spotted trait had a lower chance of
sury The trait mutated over time, causing the beetles with that trait to be lighter,
and the species evolved to have a lighter color.
In the first generation, the beetles with the dark spotted trait had a lower chance of
survival. The beetles changed their color to better adapt to their environment, and the
species evolved to have a lighter color.

Answers

Answer:

In the first generation, the beetles changed to have light spots. The beetles with the light spotted trait had a better chance of survival causing the species evolved to have lighter spots.

Answer:

In the first generation, the beetles with the dark spotted trait had a better chance of survival. The trait mutated over time, causing the beetles with that trait to be darker.

Explanation:

In the picture that I had, it shows that some of the beetles in the first generation started to develop spots on their back or wings. It shows that later down the line, their backs start to get even more darker which means that is must be a trait that mutated over time that would allow the beetles with that trait to be significantly darker. They can't just change their traits if they want to so it would have to be something like mutation that caused it.

What is a poverty line?

Answers


Description
The poverty threshold, poverty limit, poverty line or breadline, is the minimum level of income deemed adequate in a particular country. Poverty line is usually calculated by finding the total cost of all the essential resources that an average human adult consumes in one year. Hop this help you

Please help!!! How many moles are in 4.87x1024 atoms of Mg

Answers

Do you still need help with this

Something that is made out of natural resources for human use is called

Answers

Answer:

Man-made resources

Explanation:

Humanized resources are items or substances that have value to human lives that do not occur in the natural world. Examples of man-made resources include plastic, paper, soda, sheet metal, rubber and brass. These contrast with natural resources, such as water, crops, sunlight, crude oil, wood and gold.

what are the steps to naming simple ionic compounds

Answers

To name an ionic compound, you simply need to find the names of the cation and anion present in the compound and make sure to revise the ends of metal names as needed. First, write out the name of the metal, followed by the name of the non-metal with its new ending.

Answer:

To name an ionic compound, you simply need to find the names  of the cation and anion present in the compound and make sure to revise the ends of metal names as needed. First, write out the name of the metal, followed by the name of the non-metal with its new ending.

Explanation:

Write the name of the cation, and then write the name of the anion, changing the ending to "-ide" if it's a single element and leaving it as it is if it's a polyatomic ion.

Dylan is completing an experiment in science class. The teacher gave Dylan a raw egg that had the shell removed. The egg is surounded by a membrane. Dylan gently placed the egg into a solution. Below is a diagram of the concentration of water molecules in the egg and in the solution.



Based on the diagram, what will happen to the egg?
A.
It will shrink because water molecules will move out of the egg until all the water molecules are in the solution.
B.
It will swell because water molecules will move into the egg until the concentrations are equal.
C.
It will swell because water molecules will move into the egg until all the water molecules are inside the egg.
D.
It will shrink because water molecules will move out of the egg until the concentrations are equal. HELPPPPPPPPPPPPPPPPPP PLS

Answers

Answer:    AA

Explanation:

Describe the difference between ionization energy and electron affinity in terms of atomic structure.

Answers

Answer:

Please refer below to the attached file

Hope it helps

Please mark me as the brainliest

Thank you

What is the mass of 0.55 mole
of magnesium chloride?

Answers

Answer:

SYMBOLS, FORMULAS AND MOLAR MASSES

OBJECTIVES

1. To correctly write and interpret chemical formulas

2. To calculate molecular weights from chemical formulas

3. To calculate moles from grams using chemical formulas

INTRODUCTION

Part I. Symbols and formulas

An element is a homogeneous pure substance made up of identical atoms. All matter is made

up of elements and, since chemistry is the study of matter, it is convenient to use symbols to represent

the elements rather than using the entire name.

By international agreement, specific symbols are assigned to each element (Note: This means

that while names of the elements vary with language, symbols are constant throughout the world.) Each

element is assigned a one- or two-letter symbol. The first letter is capitalized, the second (if there is

one) is not. While this often seems trivial, it is in fact a very important point. For example, in chemical

language Co represents cobalt, which is a metal and an element, while CO represents carbon monoxide,

a compound which is a colorless, odorless gas! Even when there is not an obvious correspondence,

for instance "MN", it can cause confusion. Do you mean the element manganese? Did you forget a

letter and mean something else? Are you using "M" to represent something else entirely? Chemists

sometimes use "M" to represent any metal. It is well worth the trouble to memorize the symbols for

common elements.

Since compounds consist of elements, the chemical formulas of compounds also consist of

elements with subscripts used to denote the number of atoms per molecule. If there is no subscript, it is

implied that there is one of that kind of atom. Ones never appear in chemical formulas. Not only do

subscripts denote ratios of atoms, they also denote the ratio of moles of element to one mole of

compound. Parentheses can be used to show groups of atoms, with the subscripts showing how many

groups there are. Parentheses are not used if there is only one group.

Examples: For one mole of the following compounds, how many moles of each element are

present?

MgCl2 1 mole Mg, 2 moles Cl

Mg(NO3)2 1 mole Mg, 2 moles N, 6 moles O

NaNO3 1 mole Na, 1 mole N, 3 mole O

AgCl 1 mole Ag, 1 mole ClPart II. Molar Masses

Each atom has a different size and therefore a different mass. The relative masses of each

element can be found on the periodic table. For example, one atom of magnesium weighs 24.31 amu

(atomic mass units). However, one mole of magnesium weighs 24.31 g. (Moles were planned that

way!) Since one mole of MgCl2 consists of one mole of magnesium and two moles of chlorine, the

mass of one mole of MgCl2 must be the sum of the masses of the elements. The mass of one mole of a

substance is called the molar mass or molecular weight.

Examples: What is the molar mass of the following compounds?

MgCl2 24.31 + 2(35.45) = 95.21 g/mol

Mg(NO3)2 24.31 + 2(14.01) + 6(16.00) = 148.33 g/mol

NaNO3 23.00 + 14.01 + 3(16.00) = 85.01 g/mol

AgCl 107.9 + 35.45 = 143.4 g/mol

(Note: Yes! You DO have to count significant figures when calculating molecular weight/molar

mass. However, the number of significant figures may vary depending on which periodic table you use.)

Chemists are generally interested in number of moles. Unfortunately, it is impossible to measure

moles directly. However, masses are easily measured, and if the chemical formula of the compound is

known, the molar mass can be used to determine the number of moles. The molar mass is defined as:

molar mass = grams/moles = g/mol (1)

Moles may be calculated by using molar mass as a conversion factor in dimensional analysis where

molar mass in grams = 1 (exactly) mole of compound (2)

This method is used in multi-step calculations. For example, if 0.873 g of MgCl2 is weighed out, it

is 9.17 x 10-3

moles.

1 mole

0.873g x 95.21 g = 9.17 x 10-3

mol MgCl2 (3)

However, 0.873 g of AgCl is only 6.09 x 10-3

mol.

1 mole

0.873g x 143.4 g = 6.09 x 10-3

mol AgCl (4)Molar mass may also be used to relate moles to grams. For example, 0.158 mol of MgCl2 is 15.2 g.

0.158 mol x 95.21 g = 15.2 g MgCl2 (5)

1 mol

Percent is used to express parts per one hundred. Usually in chemistry, it refers to

g of species of interest x 100 = % (6)

g of whole thing

Example: For the % Mg in MgCl2: In one mole of MgCl2, there are 24.31 g of Mg (molar mass of Mg,

the part we are interested in) and 95.21 g of MgCl2 (the whole thing), so %Mg in MgCl2 is

(24.31/95.21) x 100 = 25.53% Mg (7)

PROCEDURE

Work individually.

The formula for calcium phosphate is Ca3(PO4)2. Weigh about 2 g of calcium phosphate to the

nearest 0.001 g. In other words, you do not have to have exactly 2.000g, but you must know the

weight you have exactly. Acceptable results include but are not limited to: 1.985g , 2.035g, 2.314g

etc.

Be sure to report all results with the correct number of significant figures and appropriate units!

A regional metamorphic belt is divided into zones based upon

Answers

“Mineral groups found in the rocks” would be the answer please mark me as brainliest

Consider the rate law below.

R=k[A]2

What effect does doubling the concentration have on the rate?

A. doubles the rate
B. triples the rate
C. quadruples the rate
D. no effect on the rate​

Answers

C. quadruples the rate

Further explanation

Given

The rate law :

R=k[A]²

Required

The rate

Solution

There are several factors that influence reaction kinetics :  

1. Concentration   2. Surface area   3. Temperature   4. Catalyst   5. Pressure   6. Stirring  

The rate is proportional to the concentration.

If the concentration increased, the reaction rate will increase

The reaction is second-order overall(The exponent is 2)

The concentration of A is doubled, the reaction rate will increase :

r = k[A]² ⇒ r= k[2A]²⇒r=4k[A]²

The reaction rate will quadruple.

1. How many moles of Boron is 1.25 x 1023 atoms of Boron? *
O 0.208 mol B
0 7.53 x 1046 mol B
O 1.35 x 1025 mol B
0 4.82 mol B

Answers

Answer:

0.208 mol B

Explanation:

There are 6.02 × 10^23 atoms in one mole of a substance, according to Avagadro's law.

According to this question, there are 1.25 x 10^23 atoms of Boron. This means that the number of moles in the Boron atom can be calculated thus:

number of moles (n) = number of boron atoms (nA) ÷ Avagadro's number

n = 1.25 x 10^23 ÷ 6.02 × 10^23

n = 0.2076 × 10^(23-23)

n = 0.208 × 10^0

n = 0.208 × 1

n = 0.208 moles of Boron

how many
moles are in 9.01 x 1023 molecules of water. answer should be rounded to three significant figures.
A. 1.50
B. 15.0
C. 0.150
D. None of the above

Answers

Answer:

A. 1.50

Explanation:

9.01 x 1023 molecules* 1 mol/ 6.022×1023 molecules= 1.49618067087 moles

Rounded would be 1.50

Which compound below has the highest iron content?
Feo
FeCl2
FeSO4
Fe(OH)2

Answers

ANSWER:

Fe(OH)2

Explanation:

Fe(OH)2

The highest iron content.

A compound is a substance that consists of the atoms or the ions of the two or more different elements that are joined by a chemical bond and can't be separated by any physical means. Like water is a compound of oxygen and hydrogen.

This the answer is Fe(OH)2.

The highest iron content of the iron is the second iron hydroxide, and it is an inorganic compound that makes salts from a compound of iron sulfate. Has white sold traces of oxygen which gives it a greenish tint. It can be seen in its mineralogical forms as a form of green rusting.

Hence the option D is correct.

Learn more about the compound below.

brainly.com/question/22282338.

True or False? When a gas condenses to a liquid it absorbs heat from its
surroundings.


1.True
2.False

Answers

Answer:

True

Explanation:

because it never stops doing it

PLEASEEEE HELP I WILL GIVE 30 POINTS Cobalt
Calcium
Platinum
Phosphorus

Part II:
Look at a periodic table, and in the space below type the missing chemical or symbol. Then answer the question below.

Iron:
Co:
Na:
Tin:
P:
F:
Fe:
Magnesium:
Uranium:
Ca:
Carbon:
Lead:
Ag:
Zn:
Ni:

Part III:
You have found a new element with the atomic mass of 119. In a paragraph explain where you would put in on the periodic table and why you would put it there. What type of properties would this element have? What would you call it?

Answers

Answer:

Iron: Fe

Co: Cobalt

Na: Sodium

Tin: Sn

P: Phosphorus

F: Flourine

Fe: Iron

Magnesium: Mg

Uranium: U

Ca: Calcium

Carbon: C

Lead: Pb

Ag: Silver

Zn: Zinc

Ni: Nickle

----------------

There is honestly no right answer for this but here is what I would put:

Atomic mass increases as you go from left to right. If you look at the periodic table, it would be between Sn and Sb. It would bet here because Sn is 118 and Sb is 121. Basing it off of Antimony and putting it in group 15, the properties are that it is metallic and is a poor conductor of heat. I would call it Stin, which would be shortened to St.


CuSO4 +
KI →
Cul +
12 +
K2SO4

Answers

what’s exactly is the question?

transfer of energy by electromagnetic -science question
A.conduction
B.convection
C.radiation
D.reflection

Answers

Answer:

B. convention

Explanation:

hope you get the right answer

What is the kinetic energy of a 9 kg object moving at a velocity of 5 m/s?

Answers

In classical mechanics, kinetic energy (KE) is equal to half of an object's mass (1/2*m) multiplied by the velocity squared. For example, if a an object with a mass of 10 kg (m = 10 kg) is moving at a velocity of 5 meters per second (v = 5 m/s), the kinetic energy is equal to 125 Joules, or (1/2 * 10 kg) * 5 m/s2.

Write Lewis dot structures for each of the following molecules. Use VSEPR to determine the shape of each molecule. Use electronegativity values to determine the polarity of each molecule.
PH3



CHCl3




H2CO




XeCl4




PBr5



TeF4



ICl5




BF3




KrF2




SO3

Answers

my question is butterfly emerges

PH3 i took the test and that was the aw eder

I 3. How many moles of H, gas are made when 3.2 x 1023 molecules of HCl are used? 2A1 + 6HCI ----> 2AlCl3 + 3H2​

Answers

Answer:

0.265 moles

Explanation:

From the equation given;

Number of moles of HCl is 6 while number of moles of H is 3.

Now, we know from avogadro's number that 1 mole of a gas = 6.022 × 10^(23) molecules.

We want to find the number of moles of Hydrogen gas made when 3.2 x 10^(23) molecules of HCl are used.

Thus, converting this to moles gives;

(3.2 × 10^(23))/(6.022 × 10^(23)) = 0.53 moles

Thus, we can find the number of hydrogen gas by proportion as;

n = 3/6 × 0.53

n = 0.265 moles

What happens at a constant temperature, as time progresses?

Answers -

1.Phase change

2.Bonding of particles

3.Separation of particles

4.The substance remains in its initial phase

Answers

4. it remains in its initial phase
Correct answer is 4 because the phase does not change

The diagram illustrates the water cycle.

Parts of the water cycle labeled U through Z. U: Water moving from a lake into the clouds. V: Clouds. W: Water falling from clouds as rain and snow. X: Water moving from ground to the clouds. Y: Water flowing down the mountainside into a lake. Z: Underground water going into lake.
Which process occurs at location W?

precipitation
evaporation
condensation
transpiration

Answers

Answer:

The Answer is Precipitation

Explanation:

Look it up on and then also got it right on the Unit Test and the Quiz.

The diagram illustrates the water cycle, the process that occurs at location W is precipitation. The correct option is a.

What is precipitation?

Precipitation is any product of the condensation of atmospheric water vapour that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail.

Precipitation occurs when a portion of the atmosphere becomes saturated with water vapour so that the water condenses and precipitates or falls. Thus, fog and mist are not precipitation but colloids, because the water vapour does not condense sufficiently to precipitate. Two processes, possibly acting together, can lead to air becoming saturated: cooling the air or adding water vapour to the air. Precipitation forms as smaller droplets coalesce via collision with other raindrops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are called showers.

Precipitation is a major component of the water cycle and is responsible for depositing the fresh water on the planet.

Learn more about precipitation, here:

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How many moles of Na2SO4 are present in 426.12 grams of Na2SO4? (5 points)

Group of answer choices

2

3

5

6

Answers

Answer: It’s 2.9 moles

Explanation:

Answer:

b) 3

Explanation:

i got it right

6. An unknown compound is analyzed and found to consist of 49% carbon, 2.7
% hydrogen, and 48.2 % chlorine. If the molecular mass of the compound is 150,
what is the molecular formula of the compound?

Answers

Answer:

Molecular formula = C₆H₄Cl₂

Explanation:

Given data:

Percentage of hydrogen = 2.7%

Percentage of carbon = 49%

Percentage of chlorine = 48.2%

Molar mass of compound = 150 g/mol

Molecular formula = ?

Solution:

Number of gram atoms of H = 2.7 / 1.01 = 2.67

Number of gram atoms of Cl = 48.2 / 16 = 1.36

Number of gram atoms of C = 49 / 12 = 4.08

Atomic ratio:

            C                      :           H             :           Cl

           4.08/ 1.36         :     2.67/1.36       :       1.36/1.36

            3                      :        2                 :        1

C : H : Cl = 3 : 2 : 1

Empirical formula is C₃H₂Cl.

Molecular formula:

Molecular formula = n (empirical formula)

n = molar mass of compound / empirical formula mass

Empirical formula mass = 12×3 + 1.01 ×2 + 35.5 = 73.52 g/mol

n = 150 / 73.52

n = 2

Molecular formula = n (empirical formula)

Molecular formula = 2 (C₃H₂Cl)

Molecular formula = C₆H₄Cl₂

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i just need help because i dont understand it ............................................................................... In paragraph 2, the word envisioned means, A) covered B) pictured C) switched D) turnedthe answer is B. I couldn't find this one, so here you go... I mean I couldn't find it 'cause it was really easy.. Which is the main purpose of an experimental conclusion?O A. to describe the steps in an experimentO B. to state whether a hypothesis has or has not beensupportedO C. to criticize the observations that led to the investigationO D. to explain how data was collected Who knocked over the lion?SummerJakea touristthe guide Help me please answer thanks State a, b, and the y-intercept then graph the function and describe the end behavior of the grpahs please help ill give brainliest Lunch for 4 people only $39.50 if the sales tax is 5% how much tax do they owe Please help me with this question. Harrison Company's general ledger account had a balance of $7,300 on July 31 and the following information is also available: Deposits outsanding $ 1,500 Checks outstanding 2,000 NSF checks 45 A $35 July deposit from a customer was recorded as $53 debit to Cash and credit to Accounts Receivable What is the amount of Harrison's correctd cash balance at July 31 Please help answer correctly !!!!!!!!!!! Will mark Brianliest !!!!!!!!!!!!!!!! Write an inequality for each situation.1. up to 5 people, p, visited Mary today2. the value, v, of the hat is less than $93. the number of guests, g, coming for dinner is not 8.4. the distance of the race, d , is at least 6 miles.5. the time it takes to get to grandmas house, t, is longer than 2 hours.PLS HELP I NEED IT FOR TODAY What is the Greek root that gives meaning to the word bronchitis? Please help with this question What is the final form of Socialism? What is the mass in grams of 2.5 mol of O2? Regina travels of a kilometer for every of a minute she drives. You were told that the trip from Times Square to Pelham Parkway is 72 kilometers. How many minutes would her trip have taken by car? the problem.2/3+1/3+5/3= Help meee 50 points explain ALL OF IT if you really do it ill give you 200 points pls