Guys please help me I have a final exam

a 20.0 l tank of co2 contains 68.0 grams of gas at 500.0 kpa of pressure what is the temperature of the tank ?

Answer:

For your first question, Curium does not occur naturally on Earth, meaning that it is not produced naturally on Earth. However, it can be formed in nuclear reactors.

For your second question, Curium has been used to provide power to electrical equipment used on space missions, but doesn't seem to be that important overall.

Explanation:

Hope this helped!

Answer:

1. Pollution caused the bark to become darker.

2. The light-colored peppered moth had a higher chance of survival

3. The dark-colored peppered moth had a higher chance of survival

4. During the Industrial Revolution, the barks of trees got darks, causing the moths to be seen easily on a dark background. Now predators were more likely to eat the lighter cloured moths as they were easier to find. Since fewer light-colored moths were surviving, there was a smaller likelihood of light moths surviving long enough to reproduce. Since there were fewer light-colored moths, the dark-colored moths had less competition and were able to reproduce quickly.

5. Sunny, warm place: I live in a place with lots of light and sunshine, so it would be easier for light moths to blend in with their environment long enough to reproduce and thrive.

Dark, rainy Place: I live in a place with little light and sunshine, so it would be easier for dark moths to blend in with their environment long enough to reproduce and thrive.

Explanation:

Explanation:

giving equal opportunity,making good governance, maintaining peace and harmony among people, other try to write by your self

Answer:

1. ether group R-O-R

2. benzene ring

3. 3°- alcohol

4.3°- amine group N attached to 3 groups rather than H

Answer:

C. C₆H₁₄

General Formulas and Concepts:

Chemistry - Atomic Structure

Explanation:

To find the molecular formula of the model, you simply count and add up the same elements together.

We see that we have 6 carbons and 14 hydrogens. Therefore our answer is C. C₆H₁₄

Answer:

0.6022×10²³ molecules

Number of moles = 0.1 mol

Explanation:

Given data:

Mass of HCl = 3.65 g

Number of molecules = ?

Number of moles = ?

Solution:

Number of moles:

Number of moles = mass/molar mass

Number of moles = 3.65 g/36.45 g/mol

Number of moles = 0.1 mol

Number of molecules:

1 mole of any substance contain 6.022×10²³ molecules

0.1 mol ×  6.022×10²³ molecules/ 1 mol

0.6022×10²³ molecules

The percentage composition of the alloy : 19.35% Zn, 80.65%Ag

Given

2.55 gram of an alloy

170 cc (170 ml=0.17 L) of  Hydrogen gas(H₂)

Ar Zn = 65. H=1

Required

The percentage composition

Solution

Silver remained unsolved⇒no reaction

Hydrogen gas from reaction of Zn

Zn+2HCl⇒ZnCl₂ + H₂

mol H₂ at STP (STP⇒1 mol = 22.4 L) :

[tex]\tt \dfrac{0.17}{22.4}=0.00759~moles[/tex]

From equation, mol ratio Zn : H₂ = 1 : 1, so mol H₂ = 0.00759

Mass Zn :

[tex]\tt mass=mol\times Ar\\\\mass=0.00759\times 65\\\\mass=0.49335~g[/tex]

Mass Silver :

[tex]\tt 2.55-0.49335=2.05665~g[/tex]

Percent composition :

[tex]\tt \dfrac{0.49335}{2.55}\times 100\%=19.35\%[/tex]

[tex]\tt \dfrac{2.05665}{2.55}\times 100\%=80.65\%[/tex]

Answer:

Between the small pot and the book

Explanation:

Since gravitational force is influenced by the mass of an object, the higher the mass of two objects, the stronger the gravitational force.

Thus, the force between the pot and the book is strongest, since the two have the highest mass.

Have a nice day!

Answer:

B

Explanation:

CH4 + 2 O2 → CO2 + 2 H20

12 + I X 4 → → 2 ( I X2 + 16 )

16 → → 36

25, 5 → → ?

amount of H2O = 36 X 25,5 / 16 = 57. 39

One mole or 16 g of methane gas reacts with excess oxygen to give 2 moles or 36 g of water. Then, the mass of water produced from 25.5 g of methane is 57.3 g.

Combustion is the reaction of a gas with the atmospheric oxygen producing water and carbon dioxide. The hydrocarbon gases such as methane, ethane etc easily undergo combustion reaction.

As per the given balanced reaction, one mole of methane gas CH4 produces two moles of water.

molar mass of methane = 16 g/mol

molar mass of water = 18 g/mol

mass of 2 moles of water = 36 g.

Hence, 16 g methane gas produce 36 g of water.

The mass of water produced from 25.5 grams of methane gas is then calculated as follows:

mass of water = 25.5 × 36 / 16 = 57.3 g.

Therefore, 57.3 g of water is produced in this reaction from 25.5 g of methane.

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Answer:

atoms

Explanation:

atoms combines to form compound

Answer:

The enthalpy of vaporization of H2O is higher than the enthalpy of fusion of H2O, therefore vaporizing the same mass of H2O would require more heat/energy than melting the same mass of H2O.

hope it helps!

Answer:52M

Explanation:

use S= 1000w/ MV

Here, s= molarity

w= the amount of NaCl

M= the atomic mass of NaCl

V= the volume of solution

Answer:

cesium is the largest alkali metal.

Explanation:

Answer:

Cesium

Explanation:

Cesium is the largest atom among alkali metal.

Answer:

819.45 K

Explanation:

Use the Ideal Gas Law to make sense of this problem, PV = nRT. From this equation, we know that pressure is directly proportional to temperature and that volume is also directly proportional to temperature. Therefore, doubling the temperature would double the pressure, and doubling the temperature would also double the volume. In the described scenario, the temperature is doubled twice, so the temperature is quadrupled (i.e. three times its original amount has been added).

The initial temperature was 273.15 K. Multiply this by 3 to get your answer of 819.45 K.

Answer:

1/32 of the original sample

Explanation:

edgunity got it.

13 half-lives have passed

General formulas used in decay:  

[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]

T = duration of decay  

t 1/2 = half-life  

N₀ = the number of initial radioactive atoms  

Nt = the number of radioactive atoms left after decaying during T time  

t1/2 = 4 days

Nt=18 mg (0.01% of the original isotope)

18 mg (Nt) = 0.01% No

No = the original isotope :

[tex]\tt No=\dfrac{100}{0.01}\times 18~mg=180,000[/tex]

The duration of decay  (T) :

[tex]\tt \dfrac{Nt}{No}=\dfrac{1}{2}^{T/4}\rightarrow Nt=0.01\%No[/tex]

[tex]\tt 0.01\%=\dfrac{1}{2}^{T/4}\\\\10^{-4}=\dfrac{1}{2}^{T/4}\\\\(\dfrac{1}{2})^{13}=\dfrac{1}{2}^{T/4}\\\\13=T/4\rightarrow T=52~days[/tex]

Half-lives passed :

[tex]\tt \dfrac{52}{4}=13~half-lives[/tex]

Answer:

a)

[tex]K_2=1.3x10^{2}atm^{-1/2}[/tex]

b)

[tex]PCl_5\rightarrow PCl_3+Cl_2[/tex]

[tex][PCl_5]=0.0375M[/tex]

Explanation:

Hello!

a) In this case, since we can see that the second reaction is equal to the half of the first reaction, we can relate the equilibrium constants as shown below:

[tex]K_2=K_1^{1/2}[/tex]

Thus, by plugging in the the equilibrium constant of the first reaction we obtain:

[tex]K_2=(1.6x10^4atm^{-1})^{1/2}\\\\K_2=1.3x10^{2}atm^{-1/2}[/tex]

b) In this case, for the described reaction we can write:

[tex]PCl_5\rightarrow PCl_3+Cl_2[/tex]

Thus, the corresponding equilibrium expression is:

[tex]K=\frac{[PCl_3][Cl_2]}{[PCl_5]}[/tex]

In such a way, since we know the equilibrium constant and the concentrations of PCl3 and Cl2 at equilibrium, we can compute the concentration of PCl5 at equilibrium as follows:

[tex][PCl_5]=\frac{[PCl_3][Cl_2]}{K}\\[/tex]

[tex][PCl_5]=\frac{\frac{0.20mol}{4L} *\frac{0.12mol}{4L} }{0.04}[/tex]

[tex][PCl_5]=0.0375M[/tex]

Best regards!

Answer:

D

Explanation:

If there are 2 of the same rocks on two continents, that shows that they were once merged. If there is glacial existence in places where glaciers would’ve melted (Like Africa has glacial existence from Antarctica ) this shows that continents were once merged. If life forms preserved as fossils were matched on 2 different continents this shows that all the continents were once merged.

Answer:

so i am doing this and i need help what did u get for number 1

Explanation:

its the first question

The oxidation number of Mg in Mg(OH)₂ is +2.

Hence, Option A is correct answer.

The oxidation state, or oxidation number, is defined as the hypothetical charge of an atom if all of its bonds formed with different atoms were fully ionic. It indicates the degree of oxidation of an atom in a chemical compound. Conceptually, the oxidation state may be negative, positive or zero.

Oxidation number of OH = -1

Let us suppose the oxidation number of Mg = x

Charge on compound = 0

We can write

x + 2(-1) =0

x-2=0

x = 2

Thus from the above solution we concluded that The oxidation number of Mg is +2.

Hence, Option A is correct answer.

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Answer:

The answer of 1×10 -8 is 2

base

This is the answer

Answer:

molecular formulas of the hydrocarbons

Answer:

coh3 and xxxxxxxxxxxxx

Answer:

pH = 2.98

Explanation:

pKa of HNO2 is 3.35

HNO2 reacts with NaOH as follows:

HNO2 + NaOH → NaNO2 + H2O

Where moles of NaOH added are equal to NaNO2 produced

And initial moles of HNO2 - Moles NaOH = Moles HNO2

Initial moles HNO2:

0.0200L * (0.10mol/L) = 0.00200moles HNO2

Moles NaOH = Moles NaNO2:

0.0100L * (0.10mol/L) = 0.00100 moles NaOH = Moles NaNO2

Moles HNO2:

0.00200moles - 0.00100moles = 0.00100 moles HNO2

Then, the added HCl reacts with NaNO2 producing HNO2:

HCl + NaNO2 → HNO2 + NaCl

Where moles added of HCl are moles of HNO2 produced and initial moles  of NaNO2 - moles of HCl = Moles NaNO2

Moles HCl:

4x10⁻⁵L * (10.0mol / L) = 0.00040moles HCl = Moles of HNO2 produced

Moles HNO2:

0.00100moles + 0.0004moles = 0.0014moles HNO2

Moles NaNO2:

0.00100moles - 0.0004moles = 0.0006moles NaNO2

With these moles and H-H equation we can solve for the pH of the buffer:

pH = pKa + log [NaNO2] / [HNO2]

Where pH is pH of the buffer

pKa is pKa of HNO2: 3.35

[] are moles of each species:

Replacing:

pH = 3.35 + log [0.0006moles NaNO2] / [0.0014moles HNO2]

Answer:

its C, because the cocunut tree gets energy from the sun and makes it into cocunut that is true

Explanation:

its C, because the cocunut tree gets energy from the sun and makes it into cocunut that is true

Answer:Multiple the moles of Na2 SO4 that you found just

Explanation:

Ions are formed by gaining and donating the valence electrons from the outer shells. Sodium has an extra electron and forms cations. In 1.5 grams of Na⁺, there are 0.0652 moles ions.

Cations are said to be the ions that are formed by donating electrons from their valence shell. They tend to donate their electrons to form ionic bonds with another atom that accepts the electrons.

The mass and the molar mass of the cation can be used to calculate the number of moles contained in the atom or the ion.

Given,

Mass of sodium ions = 1.50 grams

The molar mass of sodium ions = 22.98 amu

The number of moles of sodium cation is calculated as:

Moles (n) = mass ÷ molar mass

n = 1.50 ÷ 22.98

= 0.0652 moles

Therefore, 0.0652 moles are present in 1.50 grams of sodium ions.

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Answer:

1.4 x 10³

Explanation:

Given:

(3.5 x 10⁵)x(4 x 10⁻³)

Find:

Exponent form

Computation:

⇒ (3.5 x 10⁵)x(4 x 10⁻³)

⇒ 3.5 x 4 x 10²

⇒ 14 x 10²

1.4 x 10³

Answer:

B

Explanation:

Answer:

F

Explanation:

A carousel can be made to rotate using different sources of energy.  One may decide to use electric energy, manual effort, water energy or heat energy as in a candle carousel.

When the candle is lit, heat energy is supplied and warm air rises heating up the air near the carousel eventually causing it to start rotating.

Hence heat from the candle leads to a current of warm air that rises up, causing the carousel to start rotating.