khan academy sucks. can someone answer this? :)

Khan Academy Sucks. Can Someone Answer This? :)

Answers

Answer 1
Answer:

The answer is A. 80Se2-

Related Questions

Where is each conversion factor found?

Answers

Answer:

Explanation:  A conversion factor is a number used to change one set of units to another, by multiplying or dividing. When a conversion is necessary, the appropriate conversion factor to an equal value must be used. For example, to convert inches to feet, the appropriate conversion value is 12 inches equal 1 foot.

.
Characteristics of a Group of Elements
Do not conduct electricity
• Mostly gas, but brittle when solid
Has 7 valence electrons
.
Which of these elements is in this groun?

Answers

Answer:

Gas

Explanation:

I dunno but a lucky guess i guess

How do I do nunber 8?​

Answers

Answer:

DONT CLICK THAT LINK THAT IS HACK AND VIRUS

Explanation:

4) What mass of hydrogen is formed when 2.00g of magnesium
Mg + H2SO4–>H2SO4

Answers

Answer: 0.16 g H2

Explanation:

Mg+ H2SO4= MgSO4 + H2

Atomic massof Mg is 24

Molecular mass of H2 is 2

So,

24g Mg produce 2 g H2

1g Mg produce (2÷24)= 0.083 g H2

2.00g Mg produce (0.083×2) g H2

   = 0.16 g H2

 0.16g of hydrogen is formed when 2.00g of magnesium.

The mass of hydrogen gas formed when 2.00g of magnesium is equal to 0.165 g.

What is the balanced chemical equation?

The chemical equation of a reaction is said to be a balanced equation when the number of atoms of substances is equal on either side of the equation.

Evergy balanced chemical equation must follow the law of conservation of mass according to which the total mass of the substances present on the reactant side should be equal to the total mass of substances present on the product side.

Given, the balanced chemical equation of the reaction of Mg and sulfuric acid:

[tex]Mg + H_2SO_4 \longrightarrow MgSO_4 +H_2[/tex]

One mole of magnesium produces hydrogen gas = 1mol

Given the mass of magnesium = 2g

The number of moles of Mg = 2/24.3 = 0.082 mol

Then the number of moles of hydrogen gas formed = 0.082 mol

The mass of the hydrogen gas = 0.082 × 2 = 0.165 g

Learn more about the balanced chemical equation, here:

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The diagram shows the molecular structure of butane. What is the chemical
formula for butane?
Butane
H
Н

н—с-с-с-с-Н
|| []
Н н н Н
А. 4C1ОН
В. С4Н10
С. 4CH10
D. HC4H

Answers

Answer: B

Explanation: sorry if I'm too late but i just did this question and that was the right answer

how many protons electrons and neutrons does the following isotopes contain 1H+

Answers

Answer:

The other name for this isotope is a proton. This is because it contains just a  single proton.

Explanation:

H+

Protons = 1

Electrons = 1 - 1 = 0 (The + sign means it has lost a single electron)

Neutrons = 0

Please help will mark Brainliest!!!

How many grams of HCL (hydrochloric acid) can you make with 50 grams of Cl.

H + Cl -> HCL is the balanced equation

Answers

Answer:

Explanation:

It's 21 /

3Ba(C2H3O2)2 + 2K3PO4 ⟶ Ba3(PO4)2 + 6KC2H3O2

If 4.36 mol of potassium phosphate react, how many grams of barium phosphate are produced?

Answers

Hello Mistyann!

First you need to know amount of barium phosphate is

Half of potassium phosphate, also 2.18 mol.

Molar mass of Barium phosphate is 3·137.2 + 2·(30.97+4·16) g/mol

You can calculate it yourself dear.

Now mass is amount of substance · molar mass.

It has been an honour to teach you, dear,

God bless!

PLEASE HELP I WILL MARK YOU BRAINLIEST !!If you react 4.25 moles of FeCl2, how many moles of Cl2 did you also react?
PLEASE IM BEGGING FOR HELPPPPP

Answers

Answer:

2 FeCl2 + Cl2 -> 2 FeCl3

According to numbers in reaction

Amount of Cl2 is half of FeCl2

Explanation:

How are beef and gas productions related to methane levels?

Plzzz answer quick

Answers

Answer:

Cows and other ruminant animals (like goats and sheep) emit methane, a potent greenhouse gas, as they digest grasses and plants. This process is called “enteric fermentation,” and it's the origin of cows' burps.

Explanation:

Dipole-dipole interactions are (weaker than, stronger than, equal to) hydrogen bonds.

Answers

Answer and Explanation:

Dipole-Dipole interactions are weaker than hydrogen bonds.

Hydrogen bonds are a form of dipole-dipole interactions, being the strongest form of dipole-dipole interactions.

#teamtrees #PAW (Plant And Water)

Question 25 points)
Obsidian is a glassy black igneous rock. A sample of obsidian is shown.
Which type of rock forms in a similar manner as obsidian but at a slower
rate?
Oa

Ос .
Od
schist, which forms under extreme heat and pressure
conglomerate, which forms when different-sized sediments cement together
gypsum, which forms when water evaporates and leaves behind minerals
granite, which forms as magma cools deep underground

Answers

Answer:

Granite

Explanation:

Answer:

Granite

Explanation:

Igneous forms when rock is cooled and hardens by Magma.

And the option granite, which forms as magma cools deep underground

Hope it helps have a Good Day

do i have to know the chemical and physical properties of alloys? only chemistry students answer this.

Answers

Answer:

yes you do so you know how strong it is how maluble it's is so it can be customised to it's specific use

Answer:

alloy's properties are usually different from those of its component elements. Alloy constituents are usually measured by mass. Unlike pure metals, most alloys do not have a single melting point; rather, they have a melting range in which the substance is a mixture of solid and liquid.

physical properties of alloys:-

Alloy steels have a wide range of special properties, such as hardness, toughness, corrosion resistance, magnetizability, and ductility. Nonferrous alloys, mainly copper–nickel, bronze, and aluminum alloys, are much used in coinage.

chemical properties of alloys:-

Pure metals are useful but their applications are often limited to each individual metal's properties. Alloys allow metal mixtures that have increased resistance to oxidation, increased strength, conductivity, and melting point; Essentially any property can be manipulated by adjusting alloy concentrations.

dnt learn all thr properties.

these are the main properties..u can learn thse only. hope it will help u

1. Using the structural formulas for ammonia (NH3 on the left) and hexane (C6H14 on the right) below which statement explains what will happen when ammonia and hexane are mixed?


A. Hexane will dissolve with ammonia if you stir them together for 10 minutes

B. Ammonia and hexane will not dissolve because one molecule is polar and the other is non polar.

C. Ammonia and hexane will dissolve together

D. Ammonia and hexane will not dissolve because one molecule is ionic and the other is non polar


2. If you add water to 750.0 mL of a 2.800 M KCl solution, and its molarity changes to 1.500 M, what will the new volume be?


1200 mL

401.0 mL

1400 mL

800.0 mL

Answers

Answer:

1. B. Ammonia and hexane will not dissolve because one molecule is polar and the other is non polar.

2. 1400 mL

Explanation:

In chemistry, like dissolve like! Ammonia is a polar molecule having a significant dipole moment owing to its three N-H bonds. On the other hand, hexane is a purely non-polar hydrocarbon hence the two substances can never dissolve in each other.

From the dilution formula;

C1V1=C2V2

C1= Initial concentration of the solution

V1 = Initial volume of the solution

C2 = Final concentration of the solution

V2= Final volume of the solution

2.8 M * 750.0 mL = 1.5 M * V2

V2 = 2.8 M * 750.0 mL/1.5 M

V2 = 1400 mL

In a reaction 25.00mL of nitric acid required 51.4mL of 0.73M calcium hydroxide. Calculate the grams of nitric acid per liter of solution

Answers

Answer:

47.27 g HNO₃

Explanation:

The reaction between nitric acid (HNO₃) and calcium hydroxide (Ca(OH)₂) is the following:

2HNO₃(aq) + Ca(OH)₂(aq) → Ca(NO₃)₂ + 2H₂O(l)

According to the chemical equation, 2 moles of HNO₃ reacts with 1 mol of Ca(OH)₂. At the point of total neutralization, the total number of moles of  HNO₃ reacts with the total number of moles of Ca(OH)₂:

2 x moles HNO₃ = moles Ca(OH)₂

The number of moles is equal to the product of molarity of the solution (M) and the volume in liters (V):

M(HNO₃) = ?

M(Ca(OH)₂) = 0.73 M

V(HNO₃) = 25.00 mL x 1 L/1000 mL = 0.025 L

V(Ca(OH)₂) = 51.4 mL x 1 L/1000 mL = 0.0514 L

So, we can write the equation at neutralization point as:

2 x (M(HNO₃) x V(HNO₃)) = M(Ca(OH)₂) x V(Ca(OH)₂)

From this, we can calculate the molarity of HNO₃:

M(HNO₃) = (M(Ca(OH)₂) x V(Ca(OH)₂))/2 x V(HNO₃)

               = (0.73 M x 0.0514 L)/(2 x 0.025 L)

               = 0.75 M HNO₃

We can convert the molarity from M (mol/L) to g/L by using the molecular weight of HNO₃:

Mw(HNO₃) = 1 g/mol H + 14 g/mol N + (3 x 16 g/mol O) = 63 g/mol

Finally, we multiply the molarity by the molecular weight to obtain the grams of nitric acid per liter of solution:

0.75 mol/L HNO₃ x 63 g/mol = 47.27 g HNO₃

Why is there no answer

Answers

Answer:

i don't know

Explanation:

you can just ask what your question is and people reply if hey know the anwser hope this helps lol

What is the molarity of a solution made from dissolving 3.0 moles of Saline (NaCl) in 0.25 L of solution?

Answers

Answer: the answer is 12M

Explanation: 3.0mol/ 0.25L =12M

12M is the molarity of a solution made from dissolving 3.0 moles of Saline (NaCl) in 0.25 L of solution.

What is molarity?

The amount of molecules of molecules divided by the quantity of liters in solution is the definition of molarity, a concentration unit in chemistry. It is crucial to comprehend how it is calculated as well as when to employ it in comparison to other units because it is among the most widely used concentration units.

A chemical solution's concentration is measured in molarity (M). It refers to the solute's moles per liter of solution. To be clear, this is not the same as the liters of solvents (a common mistake).

molarity = number of moles of solute/ volume of solution in litre

molarity =3.0mol/ 0.25L

             =12M

Therefore, 12M is the molarity of a solution made from dissolving 3.0 moles of Saline (NaCl) in 0.25 L of solution.

To know more about molarity, here:

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Help me please I’ll give brainliest answer

Answers

Answer:

the answer is c I believe

Which is which, acid or base?

Answers

Answer:

HCI - BASE

KOH - ACID

H2SO4 - ACID

H30 + :- BASE

NAOH - ACID

Newtons law of motion​

Answers

Newton's laws of motion are three laws that describe the relationship between the motion of an object and the forces acting on it. The first law states that an object either remains at rest or continues to move at a constant velocity, unless it is acted upon by an external force. The second law explains how the velocity of an object changes when it is subjected to an external force. The law defines a force to be equal to change in momentum (mass times velocity) per change in time. The third law states that for every action (force) in nature there is an equal and opposite reaction

1. Explain where they bury remains at the Forensic Osteological Research Center and why

Answers

Answer:

In the middle of the forest.

Explanation:

They have to bury the remains in the middle of the forest at the Forensic Osteological Research Center in order to study the decomposition of the dead person. By studying the decomposition of dead person we can get a lot of information which can be used in the study of criminal cases and solving of crimes. The middle place in the forest is a perfect place to bury the remains due to presence of huge amount of microbes as well as insect that helps in the decomposition.

Select the most reactive metal from the options below
Iron
Copper
Zinc
Gold

Answers

Iron I believe is the most reactive

Answer: Hello, This is my most favorite class so I know this is right.

The most Reactive metal source is Copper.

Explanation:

This is the most reactive because it contains Lithium supplement.

Your Welcome! Mark me as Brainliest! :)

Consider the following reaction occurring in a 1.0 L container:
H2 (g) + I2 (g) → 2 HI (g)
State 2 requirements for a successful collision between H2 and I2.

Answers

Answer:

jjjjajwhejwhswjiwiwvssvwvow9qiwgdvdbslw

Temperature is a measurement of :
1) total energy in a system
2) the average kinetic energy of a system
3) the average potential energy of a system
4) the ability to do work

Answers

Answer:

Temperature is a measure of the average kinetic energy of the particles in an object. When temperature increases, the motion of these particles also increases. (That should give you the answer if you read closely first sentence)

Stoichmetric calculations must not be based on the limiting reagent
true or false

Answers

Answer:

Ture

Explanation:

Ture

True

True

True

40 g of NaCl is added to 1500 g of water. What is the molality of the resulting
solution?

Answers

Molality = moles of solute/mass (in kg) of solvent

The solute here is NaCl, of which you have 40 g or 40/58.4428 = 0.6844 moles NaCl.

The solvent here is water, of which you have 1500 g or 1.500 kg H2O.

The molality of the resulting solution would thus be 0.6844 moles NaCl/1.500 kg H2O = 0.4562 mol/kg.

If you have to consider sig figs, then your final answer would have one sig fig (40 g has one sig fig). In that case, your final answer would be 0.5 mol/kg.

Can somebody just name all the metalloids, gases, and liquids that are on the periodic table. please this is due in a hour!!!

Answers

Answer:

There are six liquid elements present in the periodic table. They are bromine,mercury ,caesium,gallium,rubidium and francium.

The metalloids; boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), polonium (Po) and astatine (At) are the elements found along the step like line between metals and non-metals of the periodic table.

The gaseous element group; hydrogen (H), nitogen (N), oxygen (O), fluorine (F), chlorine (Cl) and noble gases helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn) are gases at standard temperature and pressure (STP).

Explanation:

What is the electron configuration of the calcium ion?​

Answers

[Ar] 4s²
Let me know if you want a step by step!
Hope that helps

Answer: Calcium ion Ca² : 1 s² 2s² 2p ^6 (sorry I don't get 6 similar way as 2) 3s² 3p^6

Also 18 electrons, because Calcium donates two 4s electrons

Explanation:

how many grams of sulphur contain 3.0×1021 atoms​

Answers

Answer:

There are 0.16 g of sulphur in 3.0 × 10²¹ atoms.

Explanation:

One mole of a substance contains 6.02 × 10²³ particles

One mole of sulphur atom contains 6.02 × 10²³ atoms

Number of moles of sulphur present in 3.0 × 10²¹ atoms = 3.0 ×10²¹/6.02 10²³

Number of moles of sulphur atom = 0.00498 moles of sulphur atom

The mole of a substance is related to its mass by a quantity known as molar mass which is defined as the mass of one mole of that substance.

Molar mass of sulphur atom = 32 grams per mole (g/mol)

Mass of 0.00498 moles of sulphur atom = 0.00498 moles × 32 g/mol

Mass of sulphur = 0.16 g

Therefore, there are 0.16 g of sulphur in 3.0 × 10²¹ atoms.

The different between molecules in a liquid and molecules in a gas

Answers

Answer:

Gases, liquids and solids are all made up of atoms, molecules, and/or ions, but the behaviors of these particles differ in the three phases. ... gas are well separated with no regular arrangement. liquid are close together with no regular arrangement. solid are tightly packed, usually in a regular pattern.

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