9th grade...Chemistry help needed​

Answer:

A. Silver

Explanation:

In order to answer this question accurately, we must have a good knowledge about the position of metals in the electrochemical series.

We must know that metals that are high above in the electrochemical series displace metals that are lower in the series from their aqueous solution. This means that tin, nickel and iron  can all displace the lead from the solution of lead(II) nitrate.

However, silver is far less reactive than lead so it can not displace lead from its aqueous solution, hence the answer above.

Answer: chain reaction there will be no carbon and animals who eat plants will die off

Explanation:

Answer:

0.00021186 moles of barium nitrate

Explanation:

The given parameter is as follows;

The number of molecules of Barium nitrate Ba(NO₃)₂ = 1.2754 × 10²⁰ molecules

The number of molecule present per mole of Barium nitrate, is given by Avogadro's number, 6.02 × 10²³

1 mole of a substance contains 6.02 × 10²³ molecules

The umber of moles in a substance = (The number of molecules of the substance)/(The number of molecules per mole)

Therefore the number of moles of barium nitrate in 1.2754 × 10²⁰ molecules of barium nitrate = (1.2754 × 10²⁰)/(6.02 × 10²³) ≈ 0.00021186 moles (rounding to 5 significant figures)

The number of moles of barium nitrate present in 1.2754 × 10²⁰ molecules of barium nitrate ≈ 0.00021186 moles

Answer:

Formula we will be using:

(i) ,

where

Final quantity

Initial quantity

t=time ( same unit as that of half-life)

n=half-life

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

Given,

Final quantity ==0.100g

Initial quantity==0.750g

Time= t(unknown)

Half-life=n=3.823 days

Plug in the above values in the formula:

Divide both sides by 0.750:

Taking natural long on both sides:

Applying

Dividing both sides by ln(0.5):

Multiplying both sides by 3.823:

11.113=t

t=11.113

It would take 11.113 days

Answer : 11.113 days

Explanation:

When Iodine-131 emits a β particle will produce Xe-131

Radioactivity is the process of unstable isotopes to stable isotopes by decay, by emitting certain particles,  

So for reaction Iodine-131 :

[tex]\tt _{53}^{131}I\rightarrow _{-1}^0\beta +_{54}^{131}Xe[/tex]

Question, Answer, and Explanation are within the picture of files:

Explanation:

what is the question jjsjmwujjduwhfjd

Answer:

Volume is a physical property of an object

One unit of volume is the milliliter

Liquids and solids have constant volumes

Explanation:

The energy of a photon : 7.645 x 10⁻³⁴ J

Radiation energy is absorbed by photons

The energy in one photon can be formulated as

[tex]\large{\boxed{\bold{E\:=\:h\:.\:f}}}[/tex]

Where

h = Planck's constant (6,626.10⁻³⁴ Js)

f = Frequency of electromagnetic waves

f = c / λ , Hz

c = speed of light

= 3.10⁸  m/s

λ = wavelength ,m

wavelength λ of 2.60 ✕ 10⁻⁸ m

The energy :

[tex]\tt E=h.\dfrac{c}{\lambda}\\\\E=6.626.10^{-34}\times \dfrac{3\times 10^8}{2.6\times 10^{-8}}\\\\E=7.645\times 10^{-34}~J[/tex]

Answer:

The Answer is ground or air

Answer:

They are both solids

Explanation:

I had to answer that question a long time ago hope this helps.

Answer:

by demonstrating that the strength of the force of gravity is dependent on the masses of  objects and the distance between them

Explanation:

The model correctly proves gravity by demonstrating that the strength of the force of gravity is dependent on the masses of objects and the distance between them.

To model gravity, we need the mass of the objects and the distance between them.

According to Newton's law of universal gravitation "the force of gravity between two bodies is directly proportional to the product of their masses and inversely proportional to the square of the distance between them" .

Answer:C

Explanation:

Answer:

acceleration(a)=2m/s²

Explanation:

initial velocity(u)=0m/s

final velocity (v)=20m/s

time taken (t)=10sec

now

v=u+at

20=0+a*10

a=2m/s²

Answer:

B.18 protons 22 neutrons 18 electrons

Explanation:

Neutral atom of Argon;

     Atomic mass  = 40amu

     Atomic number   = 18

Let us find the number of the subatomic particles;

 Protons are the positively charged particles in an atom

 Electrons are the negatively charged particles

 Neutrons do not carry any charges.

Now;

  Atomic mass  = number of protons + number of neutrons

   Atomic number  = number of protons

number of protons  = 18

In a neutral atom, number of protons equals number of electrons

  number of electrons  = 18

Number of neutrons  = atomic mass - atomic number

Number of neutrons  = 40 - 18  = 22

18 protons, 18 electrons and 22 neutrons

Answer: Option C is correct

A polar molecule with nonpolar bonds

Explanation:

A polar molecule with nonpolar bonds cannot be polar because a polar molecule has net dipole that it has one end slightly positive and the other end slightly negative which allows the distribution of atoms .

Therefore it cannot have non polar bonds because non polar bonds allow electrons to be shared equally and it take place between non elemental substances or substances that are not elements , it cannot occur in elemental substances because these substances have different electronegativities which can be held by polar bonds alone.

Answer:

The correct answer is C. A polar molecule with nonpolar bonds

Explanation:

Polarity is the property of a molecule of having a dipole moment. Based on this, a molecule can be polar -with dipole moment- o nonpolar. The polarity of a molecule is determined by:

- the presence of elements with differences in electronegativity which results in polar bonds.

- geometry of the molecule

Polar bonds are vectors and if they are opposite (equal in magnitude with opposite direction) so they are cancelled out. A polar molecule must have polar bonds, buy they can be cancelled out by opposite positions in the molecule geometry. For example, CO₂ (carbon dioxide) has polar bonds C-O because they are composed by elements with different electronegativities, but the molecule is linear so the two bonds C-O are cancelled out and the molecule is nonpolar.

Therefore, from the options, the only non possible scenario is C - a polar molecule with nonpolar bonds - because polar molecules always have polar bonds. The opposite situation can be true: a non polar molecule wiith polar bonds as we saw in the example of CO₂.

Answer:

radical dudes

Explanation:

Answer:

relating to or affecting the fundamental nature of something; far-reaching or thorough.

Explanation:

Answer:

1. is B 2. is C or B

Explanation:

Answer:

a mineral ore containing copper and tin

Answer:

Copper-tin alloy

Explanation:

just took the test :D

Answer:

False

Explanation:

Just because their hair is their doesn't mean they where their during that time period or their at all. It could have been brought in by someone else's clothes.

Please award me brainliest

We can determine the culprits by extracting the fingerprints and DNAs from the hair strand taken from the crime location. But if suspected one's hair is not found from the scene does not indicated that he or she was not involved in the crime. Hence, the statement is false.

Forensic laboratories tests samples from crime scenes. There are various advanced testing methods which helps to identify the culprits of a crime. For example the hair and fingerprints, clothes or any chemical materials, blood etc. obtained from the crime scene are tested to identify its owner.

Hair is made of proteins. From each hair strand we can extract a number of DNA molecules. Thus a hair strand obtained from a crime scene can be tested and can identify its owner.

However, sometimes there will be no evidences such as hair or blood in the crime location or sometime the may some samples which are not related the culprits.

Hence, it cannot be said that if there is no hair or any sample related with the suspected one from the crime scene, that they could be exonerated. Thus the statement is falls and he/she can be a culprit which can be proved in another way.

To find more about forensic tests, refer the link below:

https://brainly.com/question/9029550

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Answer:

103

Explanation:

ee

Answer:

two hydrogen atoms and one oxygen atom

Explanation:

Answer:

What makes up a film badge?

a panel of photographic film exposed to the air

Answer:

78.8°C

Explanation:

Given parameters:

Amount of heat energy  = 130kCal

Mass of the cheese  = 2.5kg

Initial temperature  = 27°C

Unknown:

Final temperature  = ?

Solution:

To solve this problem, use the expression below;

       H = m C (T₂ - T₁)

H is the amount of heat

m is the mass

C is the specific heat capacity of water  = 4200J/kg°C

Now,

     convert the amount of heat to kJ;

            1kCal  = 4.18KJ

           130kCal  = 130 x 4.18  = 543.4kJ

Insert the parameters and solve;

       543.4 x 10³ = 2.5 x 4200 x (T₂ - 27 )

         543.4 x 10³  = 10500 x  (T₂ - 27 )

           (T₂ - 27 ) = 51.75

            T₂ = 51.75 + 27  = 78.8°C

Answer:I believe it forced convections

Explanation:convection is the circular motion that happens when warmer air or liquid makes something less dense.

Answer:

how y'all doinnn

Explanation:

byyeee

Answer:

3.88g/mL

Explanation:

Density could be understood as the mass of a compound when it occupies 1mL.

To find the mass in 1mL we need to determine the volume that the piece occupies:

Based on Archimedes' principle, the volume of water displaced is equal to volume of the aluminium piece, that is:

54.4mL - 41.8mL = 12.6mL

As the piece has as mass 48.9g, the density is:

48.9g / 12.6mL =

Answer:

its d

Explanation:

Model D shows a neutral atom of carbon as it has 6 protons in the nucleus and 6 electrons in it's orbits.

An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.

The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.

Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.

Learn more about atom,here:

https://brainly.com/question/13654549

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