Please Help. Will mark as Brainliest

Answer:

A

Explanation:

Because it is a cold winter night making the lake freeze and the bottle is already solid.

Answer:

If iron, Fe, and oxygen, O2, are in contact at high enough temperatures (and with plenty of oxygen around), the grey or reddish compound that forms is called iron(III) oxide with the formula Fe2O3

Explanation:

Iron rusts. We all know that. But the chemical reactions behind rust are surprisingly complicated! We will return to them at the end of the course when we discuss corrosion (see section 11.6 in the text). Here, we focus simply on the main compounds formed between iron and oxygen. That there is more than one may surprise you. That there are not an infinite number of them (and in fact, there almost is, as well shall see!) is an example of the law of definite proportion, an idea so central to chemistry it is almost taken for granted today.

Given parameters:

  Chemical specie = LiClO₂

Unknown:

Percentage composition of each specie = ?

Solution:

The percentage composition involves knowing the percent of total mass of a compound is made up of each of the constituent elements or groups.

Formula mass of  LiClO₂;

              7 + 35.5 + 2(16) = 74.5g/mol

The percentage composition of each species are;

%Li  = [tex]\frac{7}{74.5}[/tex] x 100  = 9.4%

%Cl  = [tex]\frac{35.5}{74.5} x 100[/tex]  = 47.7%

%O₂  = [tex]\frac{32}{74.5} x 100[/tex]  = 43.0%

Answer:

The correct answer is a

Explanation:

The formula for density is mass ÷ volume. Hence, a balance is required to determine the mass while a measuring/graduated cylinder is required to determine the volume.

The ideal measuring cylinder and balance to be used should have an uncertainty of just 0.1 ml and 0.1 g respectively. This reduces the chances of the answer gotten from the formula above to be more than 3 significant figures.

For example, if the volume to be used is 4.0 ml and the mass of this volume is 3.5 g, the density will be

Density = 3.5 ÷ 4

Density = 0.875 g/cm³ or 0.875 g/ml

NOTE that cm³ is the same measurement as mL

The answer above is in 3 significant figures

Answer:

Net force is the vector sum of forces acting on a particle or body. ... Its associated torque, the net force, becomes the resultant force and has the same effect on the rotational motion of the object as all actual forces taken together.

Answer:

Option A kinetic energy

As the bow initially was at rest it had potential energy (an object at rest potential energy) and when it was at motion it will kinetic energy (object at rest will have kinetic energy)

Explanation:

from E = mc^2 and de Broglie wavelength=h/mc

combine the eqns with respect to m(considering the body is moving with the speed of light(c))

then

E= hc/de Broglie wavelength

since, c= 3× 10^ 8

h= 6.626 × 10^ -34 and E is given, substitute the values.

sorry I don't have my calculator.

Answer:

Here are all of the organ systems with some examples of organs found in each system:

Integumentary (skin, hair, nails)

Skeletal (bones)

Muscular (smooth, cardiac, and skeletal muscles)

Circulatory (heart, arteries, veins)

Respiratory (lungs, diaphragm, larynx)

Digestive (stomach, intestines, liver)

Explanation:

Answer:

1. Cu(2+) [solution] + 2OH(-) [solution]= Cu(OH)↓ [solid]

2. 3CO3(2-) [solution] + 2Al(3+) [solution] + 3H2O [liquid] = 2Al(OH)3↓ [solid] + 3CO2↑ [gas]

2. 2PO4(3-) [solution] + 3Ba(2+) [solution] = Ba3(PO4)2↓ [solid]

Answer:

B)11

Explanation:

The atomic number is the number of protons and electrons in an atom!!

HOPE THIS HELPS!!!!!!

Answer:

we will calculate the pressure in pascals:

The units of pascal are Newtons / m²

Since we are given the force in newtons but we are given the area in cm² , we will convert 1 cm² to 1 m²

we know that 1 cm² = (1 / 10000) m²

Now, plugging these values in the equation for pressure:

Pressure = Force (N) / Area (m²)

Pressure = 450 / (1 / 10000)

Pressure = 450 * 10,000

Pressure = 4,500,000 pa

Therefore, the stilleto shoe is applying a pressure of 4.5 million pascals on the floor

We can convert it to some other units from this information

This much Pressure will be equal to:

4,500 kPa (Kilo pascals)

4.5 MPa (mega pascals)

Answer:

Answer:

Number of Significant Figures: 3

The Significant Figures are 8 2 8

Explanation:

you welcome

Answer:

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\[/tex]

From the question

mass = 16.93 g

volume = final volume of water - initial volume of water

volume = 19.7 - 11.2 = 8.5 mL

We have

[tex]density = \frac{16.93}{8.5} \\ = 1.9917647058...[/tex]

We have the final answer as

Hope this helps you

Answer:

1

The reaction is exothermic

2

[tex]H =  -1.1 \  KJ[/tex]

3

[tex]\Delta H_{rxn} = -6.24 \  KJ/ mol[/tex]

Explanation:

From the question we are told that

  The mass of the sodium chloride is (NaCl ) is  [tex]m_s =  10.3 \  g[/tex]

  The mass of water is  [tex]m_w  =  250 \  g[/tex]

  The initial  temperature is  [tex]T_i =  23^oC[/tex]

   The temperature after 3 minutes is  [tex]T_3 =  22.2 ^oC[/tex]

   The time taken for temperature to fall is  t =  3 minutes

The  reaction is

       [tex]NaCl_{ (s)} \rightarrow Na^+ _{(aq)} + Cl^-_{ (aq)}[/tex]

The reaction is exothermic because the temperature fell  

Generally the mass of the solution is  mathematically represented as

           [tex]M  =  m_w   +  m_s[/tex]

=>        [tex]M  =  250  +    10.3 [/tex]

=>        [tex]M  =  260.3 \ g [/tex]

Gnerally the heat energy released from the solution is mathematically represented as

       [tex]H =  M  *  C_s * (T_3 -  T_i)[/tex]

Here [tex]C_s[/tex] is the specific heat of solution which for this question we would assume it is the specific heat of water which has a value of

    [tex]Cs = C_w = 4.18 J/g^oC[/tex]

So

   [tex]H =  260.3  *  4.18 * (22-  23)[/tex]  

    [tex]H =  -1088.054 \  J[/tex]  

      [tex]H =  -1.088054 \  KJ[/tex]  

     [tex]H =  -1.1 \  KJ[/tex]

Generally the number of moles of NaCl is mathematically represented as

     [tex]nNaCl =  \frac{m_s}{zNaCl}[/tex]

Here  [tex]zNaCl[/tex] is the molar mass of NaCl  and the value is

   [tex]zNaCl =  58.44 \ g/mol[/tex]

So

      [tex]nNaCl =  \frac{10.3}{58.44 }[/tex]

=>    [tex]nNaCl =  0.1762 \  moles[/tex]

Generally reaction enthalpy is mathematically represented as

         [tex]\Delta H_{rxn} =  \frac{H}{nNaCl}[/tex]

         [tex]\Delta H_{rxn} =  \frac{-1.1}{0.1762 }[/tex]

         [tex]\Delta H_{rxn} = -6.24 \  KJ/ mol[/tex]

Answer:

NH3 is the most likely covalent compound  

Explanation:

Other Choices are:

LiF- Ionic compound  

MgS- ionic compound  

CaCl2- ionic compound  

The most likely to have a covalent bond is NH₃. The correct option is c. covalent bonds are the strongest bonds among all.

A covalent bond is formed between two atoms by the mutual sharing of one or more pairs of electrons. The two atomic nuclei attract these electrons at the same time. When the difference in electronegativities of two atoms is too tiny for electron transfer to produce ions, a covalent bond occurs.

The unequal sharing of electrons between the combining atoms results in the formation of a polar covalent bond. The equal sharing of electrons between the combining atoms results in the formation of a non-polar covalent bond.

LiF- Ionic compound  

MgS- ionic compound  

CaCl₂- ionic compound  

Therefore, the correct option is c, NH₃.

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Answer:

Independent variable in independent where the dependent variable relays on the independent one.

Explanation:

Look in the names and above.

Answer:

why cant you just say the grasshopper eats the marsh grass the shrew eats the grasshopper and the hawk eats the shrew.

Explanation:

this makes sense to me but im not sure.

Answer:

the hawk eats both the snake and the shrew and so does the snake eat the shrew and frog and ex...

Explanation:

Answer:

Compound

Explanation:

The sample given to the students is a mixture.

A mixture is composed of substances that are not chemically combined together. The components of a mixture all retain their individual properties. So in a mixture, we can easily notice the individual components if the mixture is heterogeneous.

Clearly, the students were given a heterogeneous mixture because one student observed that the sample is;

Based on these observations, other students can agree that the sample is a mixture.

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Answer:

Molecules move freely around since they don't have a definite shape. This is the reason water stays liquid and couldn't be gripped.

Answer:

4.38g

Explanation:

70.0/2 = 35g - 20 mins

35/2 = 17.5g - 40 mins

17.5/2 = 8.75g - 60 mins

8.75/2 = 4.375g - 80 mins

4.375 g of the carbon 11 would be remaining after 80 minutes.

Half life is the time taken for a substance to decay to half of its original value. It is given by:

[tex]N(t)=N_o(\frac{1}{2})^{\frac{t}{t_\frac{1}{2} } } \\\\\\Where\ t_\frac{1}{2}\ is\ half\ life,N_o\ is\ original\ amount,t\ is\ time,N(t)\ is\\amount\ remaining\\\\\\Given\ that\ N_o=70,t_\frac{1}{2}=20,t=80, hence:\\\\N(t)=70(\frac{1}{2} )^\frac{80}{20}=4.375\ g[/tex]

Therefore, 4.375 g of the carbon 11 would be remaining after 80 minutes.

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Answer:

the transition from water to steam is call evaporation.

Explanation:

water evaporates or vaporizes and turns into steam this typically happens when heat meets with the water. an example would be if you boil water steam will release from the pot, or when it rains, snows, etc (precipitation) the water evaporates and the ground dries.

This answer should have four signifigant features

Explanation:

I had this on a test and got it right  :D

Answer:

601mmhg

Explanation:

Pgas = Patm - hρg

Height of water = 14.4cm

Convert to mm

1 cm = 10mm

14.4 cm =

= 14.4cm × 10mm

= 144mm

hpg = 144 mmhg

Ptotal = Patm - hog

= 745mmhg - 144 mmhg

= 601mmhg

The total pressure of gases inside the graduated cylinder = 601mmhg

Answer:

An electron has a Negative charge or -1

Answer:

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\ [/tex]

From the question

mass = 3 g

volume = 5 cm³

We have

[tex]density = \frac{3}{5} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

Explanation:

Molar mass of Argon

= 35.96755 x .00337 + 37.96272 x .00063 + 39.96240 x .99600

= .12121 + .0239165 + 39.80255

= 39.95

Molar mass of silicon

27.97693 x .9223 + 28.97649 x .0467 + 29.97376 x .0310

= 25.803 + 1.35320 + .929

= 28.08

b )

No of atoms of Si  in 78.2 g = 78.2 x 6.02 x 10²³ / 28.08

= 16.76 x 10²³ .

c )

42 Ar / 40 Ar = 1.05006

42 Ar / 39.95 = 1.05006

42Ar = 41.95

2 )

C₁₆H₁₅F₂N₃O₄S

Mol weight = 16 x 12 + 1 x 15 + 2 x 19 + 3 x 14 + 4 x 16 + 32

= 192 + 15 + 38 + 42 + 64+ 32

= 383

No of molecules = .078 x 6.02 x 10²³ / 383

= 1.226 x 10²⁰ molecules .

Answer:

It's too short. Write at least 20 characters to explain it well.

Explanation:

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Answer:

red, yellow, blue are the 3 main primary colors

Answer:

An element with 7 valence electrons will most likely  be a halogen and gain an electron

Explanation:

The element with 7 valence electrons is a halogen. Halogen group contains fluorine, chlorine, bromine, iodine and astatine.

Halogens are 17th group elements in periodic table. They are gases and shows high electronegativity. Halogens are p block elements.

The group number in periodic table is given assigned by adding 10 to the number of valence electrons if the no of valence electrons is 3 or more. Elements containing 1 or 2 valence electrons are in group 1 and 2 respectively.

Thus, if the number of valence electron 7 then, the element is in group 17 and it is a halogen.

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