Chemistry, please help

Answer:

9 g

Explanation:

Chemical equation:

CH₄ + 2O₂    →       CO₂ + 2H₂O

4        16                 11         9

4+16 = 20               11+9 = 20

9 gram of water must be produced because according to law of conservation of mass, mass neither created nor destroyed thus on both side of equation mass must be same.

Law of conservation of mass:

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

This law was given by French chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

For example:

6CO₂ + 6H₂O + energy → C₆H₁₂O₆ + 6O₂

there are six carbon atoms, eighteen oxygen atoms and twelve hydrogen atoms on the both side of equation so this reaction followed the law of conservation of mass.

Answer: combustion causes a chemical reaction between nitrogen and oxygen in the engine.

Explanation:

Nitrogen oxides are produced in combustion processes, partly from nitrogen compounds in the fuel, but mostly by direct combination of atmospheric oxygen and nitrogen in flames. Nitrogen oxides are produced naturally by lightning, and also, to a small extent, by microbial processes in soils.

Answer:

when fuels are burned in vehicle engines high temperatures are reached. at these high temperature nitrogen and oxygen from the air combine to produce nitrogen

Answer:

DNA, or Deoxyribonucleic acid, has three types of chemical component: phosphates, a sugar known as deoxyribose, and four nitrogenous bases which are:

-adenine

-guanine

-cytosine

-thymine.

Two of the bases, adenine and guanine, have a double-ring structure characteristic of a type of chemical called a purine.

Hope this helped,

Philip

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Answer:

1.36 Myr or 717 kyr.

Explanation:

Answer:

Half life of quartzs means natural decay of radioactive material.

Explanation:

Fluorine's atomic configuration is (2,7). As it's charge is -1, it will have 8 electrons in it's outermost shell thus filling its octate. similarly, Sodium loses one electron.

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Answer:

Neutral

Explanation:

A pH below 7 is acidic and a pH above 7 is basic, and a pH of 7 is neutral.

Answer:

There are four phases of matter.

Explanation:

There are the three phases you normally hear about: solid, liquid and gas.

However, there is also a fourth named plasma.

PLS GIVE BRAINLIEST

Answer:

Explanation:

Firstly, it should be noted that melting and freezing points are the same. Thus, when a substance melts at a certain temperature, it means it can also start freezing/solidifying at that same temperature. That been said, when the substance P is a solid at a certain temperature, the other compound Q will boil at that same temperature and hence will be a gas at that same temperature.

If P is solid, it simply means that Q must still be in the liquid state.

From the question, we can see that, the melting point of P and the boiling point of Q are the same. The melting point of a substance is the temperature at which the solid turns to liquid while the boiling point of a substance is the temperature at which a liquid turns to a gas.

If P is solid, it simply means that Q must still be in the liquid state. It has not yet started boiling since the melting point of P and the boiling point of Q are the same.

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Answer:

here's your answer...

Explanation:

Full moon, also hey lol.

have a germ-free day.

Answer:

8 electrons

Explanation:

Magnesium is present on group 2.

It has 2 valence electrons.

Electronic configuration of magnesium:

Mg₁₂ = 1s² 2s² 2p⁶ 3s²

1st energy level contain 2 electrons.(1s²)

2nd energy  level contain 8 electrons. (2s² 2p⁶)

3rd energy level contain 2 electrons. (3s²)

3rs energy level of magnesium is called valence shell. It contain two valance electrons. Magnesium can easily donate its two valance electrons and get stable electronic configuration.

It react with halogens and form salt. For example,

Mg + Cl₂   →   MgCl₂

Answer:

Cells and tissue

Explanation:

Cells are the smallest functional units of all living things

Tissue is organic material from which organs and their bodily structures appear

Answer:

Srry its so hard

Explanation:

The difference between naming ionic and covalent compounds is that, in ionic compounds the ending of the second element changes to -ide, but not in covalent compounds.

Ionic compounds are compounds that are formed by the by the transfer of electrons from a metal to a nonmetal. Covalent compounds are formed when electrons are shared between nonmetals.

For ionic compounds, the name of the second element(the nonmetal) often ends in -ide. For instance; sodium bromide, cesium oxide and potassium nitride. This does not apply when naming covalent compounds. The are named based on the subscripts of each element in the compound.

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Answer:

P2 = 226.6 kPa (Approx)

Explanation:

Given:

Temperature t =  25ºC

Old volume v1 = 145 ml

Old pressure p1 = 125 KPa

New volume v2 = 80 ml

Find:

New pressure p2

Computation:

p1v1 = p2v2

125 x 145 = P2 x 80

P2 = 226.6 kPa (Approx)

Answer:

Monosaccharides, these are the simplest building block of carbs

Explanation:

Answer:

You can make the ramp really steep and hold the marble at the top of it

Explanation:

The statement of two ways in which increase the potential energy that is "potential energy is declining, while its kinetic energy is rising. Due to friction, potential energy is also transformed into heat."

Potential energy is the energy stored in an object due to its location relative to some zero position, that objects can be compressed such as rubber bands, trampolines, and bungee cords are examples of potential energy.

A marble dropped at the top of the ramp seems to have more gravitational force than one discharged further down the ramp, and that potential energy is turned into kinetic energy when the marble is again dropped and begins to roll down the ramp.

Learn more about potential energy here

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Answer:

Explanation:

before the reaction you have K=2 and Cl=4

after the reaction K=2 and Cl=2 so it does not follow the law of conservation

Answer:

A good society has a transparent talk, they share all matters related to the society, hence everyone knows what's going on. This is why collectiveness leads to a good society.

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Answer:

197.5pm

Explanation:

Given parameters:

Diameter of the atom  = 395pm

Unknown:

Radius of the atom  =?

Solution:

Radius is the half of diameter;

  Radius = [tex]\frac{diameter}{2}[/tex]

 Radius  = [tex]\frac{395}{2}[/tex]   = 197.5pm

Answer:

C) LiOH + HCl → LiCl + H₂O

General Formulas and Concepts:

Chemistry - Reactions

Explanation:

Step 1: Define

RxN A:   2Na + 2H₂O → 2NaOH + H₂

RxN B:   CaCO₃ → CaO + CO₂

RxN C:   LiOH + HCl → LiCl + H₂O

RxN D:   CH₄ + 2O₂ → CO₂ + 2H₂O

Step 2: Identify

RxN A:   Single Replacement Reaction

RxN B:   Decomposition Reaction

RxN C:   Double Replacement Reaction

RxN D:   Combustion Reaction

Explanation:

Appearance, melting point, density, solubility, polarity

Answer:

D. [tex] O^{2-}[/tex]

Explanation:

In Chemistry, electrons can be defined as subatomic particles that are negatively charged and as such has a magnitude of -1.

Valence electrons can be defined as the number of electrons present in the outermost shell of an atom. Valence electrons are used to determine whether an atom or group of elements found in a periodic table can bond with others. Thus, this property is typically used to determine the chemical properties of elements.

Oxygen has a total number of eight (8) electrons and as such the [tex] O^{2-}[/tex] is able to gain (receive) two (2) more electrons in order to have the same electron arrangements as the noble gas i.e an atom of neon that has a total number of ten (10) electrons.

Hence, [tex] O^{2-}[/tex] contains the same number of electrons as an atom of neon.

Ionic compounds are formed from metal and non-metal elements

The chemical formula of compounds (especially ionic compounds) can be determined from the charge of each ion.

Determination of the ionic charge of the constituent elements of the compound can be seen from the electron configuration to achieve stability according to the octet rule

The charge of each ion will be crossed in the compound

Aluminum bromide

Al³⁺ + Br⁻ ⇒ AlBr₃

Magnesium bromide

Mg²⁺ + Br⁻ ⇒ MgBr₂

Sodium sulfide

Na⁺ + S²⁻ ⇒ Na₂S

Sodium nitride

Na⁺ + N³⁻ ⇒ Na₃N

Answer:

Metamorphic rocks form when heat and pressure transform an existing rock into a new rock. Contact metamorphism occurs when hot magma transforms rock that it contacts. Regional metamorphism transforms large areas of existing rocks under the tremendous heat and pressure created by tectonic forces.

Explanation: