What does this image represent?
a) alcohol group
b) carbonyl group
c) ether group
d) hydroxyl group

Answer: It is the principle that matter cannot be created or destroyed.

Explanation:

Answer:

Explanation:

half life = 4 h

initial concentration = 100

final concentration = 15

Time = t

No of half life  x = t / 4

15 = 100 x ( 1/2 )ˣ

.15 =  ( 1/2 )ˣ

ln .15 = - x ln2

x = - ln .15 / ln 2

= 1.897 / .693

x = 2.737

x = t / 4

t = 2.737 x 4 = 11 h approx .

Answer:

a) - 0.2 M

b) - 0.2 M

c)- 0

Explanation:

The chemical formula of copper (II) bromide is CuBr₂. Its molar mass (MM) is calculated as follows:

MM(CuBr₂)= MM(Cu) + (2 x MM(Br) = 63.5 g/mol + (2 x 80 g/mol)= 223.5 g/mol

a). Molarity = moles CuBr₂/1 L solution

moles CuBr₂ = mass/MM = 18.7 g x 1 mol/223.5 g = 0.084 mol

Volume in L = 375 mL x 1 L/1000 mL = 0.375 L

M = 0.084 mol/(0.375 L) = 0.223 M ≅ 0.2 M

b). When is added to water, CuBr₂ dissociates into ions as follows:

CuBr₂ ⇒ Cu²⁺ + 2 Br⁻

We have 1 mol Cu²⁺ (copper (II) cation) per mol of CuBr₂. Thus, the concentration of copper (II) cation is:

0.2 mol CuBr₂ x 1 mol Cu²⁺/mol CuBr₂ = 0.2 M

c). The concentration of acetate anion is 0. There is no acetate anion in the solution (the anion from CuBr₂ is bromide Br⁻).

Answer:

Complete question is;

What is the frequency of light emitted when the electron in a hydrogen atom undergoes a transition from energy level n=6 to level n=3?

Answer:

Frequency = 2.742 × 10^(14) s^(-1)

Explanation:

First of all, the energy of hydrogen electron from online values is;

E_n = -2.18 × 10^(-18) × (1/n²) J

n is the principal quantum number

We are told that hydrogen atom undergoes a transition from energy levels n = 3 to n = 6.

Thus, it means we have to find the difference between the electrons energy in the energy levels n = 3 to n = 6.

Thus;

E_n = E_6 - E_3

Thus;

E_n = [-2.18 × 10^(-18) × (1/6²)] - [-2.18 × 10^(-18) × (1/3²)]

E_n = (2.18 × 10^(-18)) × [-1/36 + 1/9]

E_n = 0.1817 × 10^(-18) J

From Planck expression, we can find the frequency. Thus;

E = hf

Where h is Planck's constant = 6.626 × 10^(-34) m²kg/s

Thus;

0.1817 × 10^(-18) = 6.626 × 10^(-34) × f

f = (0.1817 × 10^(-18))/(6.626 × 10^(-34))

f = 2.742 × 10^(14) s^(-1)

Answer:

D

Explanation:

i did it before

Answer:

The moon is only visible during part of each month. ... When the moon is opposite the sun in the sky (which is when full moon happens), it will rise as the sun sets and set as the sun rises. Therefore, a full moon will be up all night long, but not during the day.

Explanation:

During full moon, the sun and moon will be in opposite sides. The illuminated portions of moon can be seen only in night in earth.

Full moon appears once in a every lunar cycle. That is the full part of moon is visible at this time. After the first two quarters, moon passes to waxing gibbous state, and then turns to full moon.

The moon's lit side faces earth's night side at the time of the full moon, when the sun and moon are on opposite sides of the planet. Therefore, a full moon is  only visible at night.

It is quite possible that you saw a full moon at least one day before or after the real full moon  phase if you have ever seen one shortly after dawn or just before sunset.

Rarely, under ideal circumstances, you could even be able to view a real full moon rising or setting opposite the sun, quite near the horizon. However, the moon typically never rises over the horizon.

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Answer:

1.61 x 10²⁰ molecules

Explanation:

Given parameters:

Mass of the hydrogen gas  = 8.01 x 10⁻⁴g

Unknown

Number of molecules of NH₃ = ?

Solution:

Given reaction:

                     N₂  +  3H₂   →   2NH₃

We have to solve from the known to the unknown

             find the number of moles of the specie;

    number of moles = [tex]\frac{mass}{molar mass}[/tex]

     Molar mass of H₂ = 2(1) = 2g/mol

   Number of moles  = [tex]\frac{0.0008}{2}[/tex]   = 0.0004mol

      0.0004 moles of H₂ will produce [tex]\frac{0.0004 x 2}{3}[/tex]   = 0.00027moles of NH₃

   1 mole of a substance contains 6.02 x 10²³ molecules

     0.00027mole of NH₃ will contain 0.00027 x 6.02 x 10²³

                               = 1.61 x 10²⁰ molecules

Answer: Chlorine.

Explanation:

Since chlorine's 17 protons are greater than magnesium's 12 protons, chlorine will have a greater effective nuclear charge to draw chlorine's valence electrons closer to the nucleus and, thus, chlorine is expected to have the smaller atomic radius, while magnesium with the lower effective nuclear charge is expected to have a smaller amount of radius.

Answer: The largest one, and answer is Sand

Explanation:

Answer:

humus

Explanation:

Answer:

2.01 g H₂

Explanation:

The chemical equation for the electrolysis of water is

2 H₂O  ⇒  2 H₂  +  O₂

Convert grams of water to moles.  The molar mass of water is 18.016 g/mol.

(36 g)/(18.016 g/mol) = 1.998 mol H₂O

Convert moles of water to moles of hydrogen by using the mole ratio.  By looking at the chemical equation, you can see that for every 2 moles of water consumed, 2 moles of hydrogen is produced.

(1.998 mol H₂O) × (2 mol H₂/2 mol H₂O) = 1.998 mol H₂

Now that you have moles of hydrogen, you can convert to grams.  The molar mass of hydrogen is 1.008 g/mol.

(1.998 mol) × (1.008 g/mol) = 2.01 g H₂

You will produce 2.01 grams of hydrogen

Answer:

[tex]M=44.06\frac{g}{mol}[/tex]

Explanation:

Hello.

In this case, knowing the temperature, density and temperature of Y which behaves ideally, we can write the ideal gas equation:

[tex]PV=nRT[/tex]

Whereas the moles are equal to the mass over the molar mass of Y:

[tex]PV=\frac{m}{M} RT[/tex]

Thus, solving for the molar mass we write:

[tex]M=\frac{mRT}{PV}[/tex]

Yet, since density is mass of over volume, we then write:

[tex]M=\frac{\rho RT}{P}[/tex]

Considering the pressure in atm and the density in g/L:

[tex]P=95.3kPa*\frac{1atm}{101.325kPa}=0.941atm\\\\\rho=1.696\frac{g}{dm^3} *\frac{1dm^3}{1L}=1.696\frac{g}{L}[/tex]

Therefore, by plugging the values in, we obtain:

[tex]M=\frac{1.696\frac{g}{L} *0.082\frac{atm*L}{mol*K}*298K}{0.941atm}\\\\M=44.06\frac{g}{mol}[/tex]

Thus, the gas may be propane ([tex]C_3H_8[/tex]) since it molar mass is 44.11 g/mol.

Best regards!

the bigger the object the more weight of the planet or gravity is acted upon if

Answer:

Wadding is a disc of material used in guns to seal gas behind a projectile or to separate powder from shot. ... Wadding for muzzleloaders is typically a small piece of cloth, or paper wrapping from the cartridge.

Explanation:

Answer:

The Group 1 elements in the periodic table are known as the alkali metals. They include lithium, sodium and potassium, which all react vigorously with water to produce an alkaline solution.

Explanation:

Answer:

the process of plants taking the sunlight and turning it into food for the plant.

Explanation:

Answer:

H. 2 blue, 3 yellow, and 12 green

Explanation:

Aluminium atoms (Al) = Blue Beads

Oxygen Atoms (O) = Green Beads

Sulfur (S) = Yellow beads

From the compound Al2(SO4)3, the number of atoms present are;

Al = 2

S = 3

O = 12

This means the model would contain;

2 Blue beads

12 Green beads

3 Yellow beads

The correct option is; H. 2 blue, 3 yellow, and 12 green

Answer:

H

Explanation:

Al(blue):2

S(yellow):3

O(green):4*3=12

so 2 blue beads 3 yellow beads and 12 green beads don't time the 2*3 it's not the same compound

good luck!!!

Answer:

See explanation

Explanation:

a) -About 1-2 drops of the unknown is dissolved in approximately 1 mL of analytical grade acetone standard solution. The test solution is added and shaken thoroughly.  If a positive test is not immediately observed, the set should be allowed to stand for 1-2 minutes. A positive result means the appearance of a green color.

b) The functional groups that can be distinguished by the test are alcohols and aldehydes.

Aldehydes give a positive test to chromic acid but ketones do not.

Primary and secondary alcohols give a positive test to chromic acid but tertiary alcohols do not.

c) Chromic Acid Test involves Cr in the +6 oxidation state. A positive test implies the reduction of orange Cr^6+ to green chromium Cr^3+.

d) The compounds were not shown but this image attached from lumen learning summarizes the reaction mechanism of chromic acid test.

Answer:

gill lamellae

Explanation:

Gills  in fishes are structures that permit fish to carry out gaseous exchange in water.  Fishes exchange gases  such as oxygen and carbon dioxide using gills.

Fish gills carry out their activity mainly through its major component called the  gill lamellae. These are comb-like filaments which help increase the surface area of the gills in order to facilitate gaseous exchange

Answer:

i

[tex]J_{m} = 20 [/tex]

ii

[tex]J_{m} = 22.5 [/tex]

Explanation:

From the question we are told that

  The first temperatures is [tex]T_1 =  25^oC =  25 +273 =298 \ K[/tex]

   The second temperature is  [tex]T_2 =  100^oC =  100 +273 = 373 \ K[/tex]

Generally the equation for  the most highly populated rotational energy level is mathematically represented as

     [tex]J_{m} = [ \frac{RT}{2B}]  ^{\frac{1}{2} } - \frac{1}{2}[/tex]

Here R is the gas constant with value [tex]R =8.314 \ J\cdot K^{-1} \cdot mol^{-1}[/tex]

Also  

      B is given as [tex]B=\ 0.244 \ cm^{-1}[/tex]

   Generally the energy require per mole to move 1 cm is  12 J /mole

So   [tex]0.244 \ cm^{-1}[/tex]  will require x J/mole

           [tex]x =  0.244 *  12[/tex]

=>          [tex]x =  2.928 \ J/mol [/tex]

So at the first temperature

     [tex]J_{m} = [ \frac{8.314 * 298  }{2*  2.928 }]  ^{\frac{1}{2} } - 0.5 [/tex]

=>  [tex]J_{m} = 20 [/tex]

So at the second temperature

           [tex]J_{m} = [ \frac{8.314 * 373  }{2*  2.928 }]  ^{\frac{1}{2} } - 0.5 [/tex]

=>  [tex]J_{m} = 22.5 [/tex]

Answer:

ARSENIC

Explanation:

It has an atomic number of 33

Answer:

2 C 2 H 2 ( g ) + 5 O 2 ( g ) ⟶ 4 C O 2 ( g ) + 2 H 2 O ( l )- combustion reaction

N H 4 N O 3 ( s ) ⟶ N 2 O ( g ) + 2 H 2 O ( l )- decomposition reaction

C O ( g ) + 2 H 2 ( g ) ⟶ C H 3 O H ( l ) - combination reaction

2 F e ( s ) + 6 H C l ( a q ) ⟶ 2 F e C l 3 ( a q ) + 3 H 2 ( g )- Redox reaction

C a C l 2 ( a q ) + N a 2 C O 3 ( a q ) ⟶ 2 N a C l ( a q ) + C a C O 3 ( s )- double displacement reaction

Explanation:

We can determine the type of reaction by considering the reactants and products.

Combustion is a reaction between a substance and oxygen which produces heat and light. The first reaction is the equation for the combustion of ethyne.

A decomposition reaction is one in which a single reactant breaks down to form products. The second reaction is the decomposition of ammonium nitrate.

A  combination reaction is said to occur when two elements or compounds react to form a single product. The third reaction is the combination of carbon dioxide and methane to form  methanol.

An oxidation-reduction reaction is a reaction in which there is a change in oxidation number of species from left to right of the chemical reaction equation. The fourth reaction is the oxidation of iron (0 to +3 state) and reduction of hydrogen (+1 to 0 state).

A double displacement reaction is a reaction in which ions exchange partners from left to right in the reaction equation. The fifth reaction is a double displacement reaction. Both Na^+ and Ca^2+ exchanged partners from left to right of the reaction equation.

Reactions are the formation of the products from the reactant. The types of reactions are combustion, decomposition, combination, Redox and double displacement.

The reaction is a chemical change in the properties of the reactant that forms the products. It can be of various types based on the formation of the product.

The first reaction is combustion as the reactants react and use oxygen to form heat, carbon dioxide and water. The combustion reaction of ethyne can be shown as,

[tex]\rm 2 C _{2} H _{2} ( g ) + 5 O _{2} ( g ) \rightarrow 4 C O _{2} ( g ) + 2 H _{2} O ( l )[/tex]

The second reaction is decomposition in which a single reactant decomposes to form two or more products. The decomposition of ammonium nitrate can be shown as,

[tex]\rm N H _{4} N O _{3} ( s ) \rightarrow N _{2} O ( g ) + 2 H _{2} O ( l )[/tex]

The third reaction is a combination reaction in which two compound or elements combines to form one product. The combination reaction between carbon monoxide and hydrogen to form methanol can be shown as,

[tex]\rm C O ( g ) + 2 H _{2} ( g ) \rightarrow C H _{3} O H ( l )[/tex]

The fourth reaction is redox and includes the oxidation and the reduction of the species of the reaction. In the reaction, iron undergoes oxidation and hydrogen reduction. The redox reaction can be shown as,

[tex]\rm 2 F e ( s ) + 6 H C l ( a q ) \rightarrow 2 F e C l _{3} ( a q ) + 3 H _{2} ( g )[/tex]

The fifth reaction is a double displacement reaction in which the calcium and sodium interchange their position in the product formation. The reaction can be shown as,

[tex]\rm C a C l _{2} ( a q ) + N a _{2} C O _{3} ( a q ) \rightarrow 2 N a C l ( a q ) + C a C O _{3} ( s )[/tex]

Therefore, the type of reactions is 1. combustion, 2. decomposition, 3. combination, 4. redox and 5. double displacement.

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Answer:

less, decreases

Explanation:

When the pressure of an atmosphere occurs because of the force exerted so at the time of the higher altitudes, the air mass i.e. above the earth should be less as the air is attracted towards surface of an earth because of the gravity and air contains the mass that shows near the surface area so automatically the air density reduced due to which the mass also decreased

Answer:

Elements in the same group of the periodic table have the same number of valence electrons. These are the electrons in their outer energy level that can be involved in chemical reactions. ... All the elements in group 1 have just one valence electron. This makes them very reactive.

Explanation:

Answer:

0.0836 mol

Explanation:

A chemist measured the amount of calcium sulfide produced during an experiment. She finds that 6.03 g of calcium sulfide is produced. Calculate the number of moles of calcium sulfide produced.

Step 1: Given data

Mass of calcium sulfide: 6.03 g

Step 2: Determine the chemical formula of calcium sulfide

Calcium cation has a charge +2 and sulfide anion has a charge -2. Then, the chemical formula of calcium sulfide is CaS

Step 3: Calculate the moles corresponding to 6.03 g of CaS

The molar mass of CaS is 72.14 g/mol. The moles corresponding to 6.03 g of CaS are:

6.03 g × (1 mol/72.14 g) = 0.0836 mol

Answer:

Reactions of Metals with Water

Metals with moderate to low reactivity react very slowly with water. However, they react moderately with steam when heated and give hydrogen gas and metal oxides. Metals low in the metal reactivity series do not react with water even at high temperature.

Explanation:

Order of reactivity                     Metal               Reactions with water or steam

↑                                           sodium (Na)         Vigorous reaction with cold water

↓                                        calcium (Ca)    Less vigorous reaction with cold water

least reactive           magnesium (Mg)    Slow reaction with cold water, vigorous                                                                                                   .                                                                 with hot water

Answer:

Percentage yield of carbon dioxide is 49.9%

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

2CH3(CH2)2CH3 + 13O2 —> 8CO2 + 10H2O

OR

2C4H10 + 13O2 —> 8CO2 + 10H2O

Next, we shall determine the masses of butane and oxygen that reacted and the mass of carbon dioxide produced from the balanced equation. This is illustrated below:

Molar mass of butane C4H10 = (12×4) + (10×1)

= 48 + 10

= 58 g/mol

Mass of C4H10 from the balanced equation = 2 × 58 = 116 g

Molar mass of O2 = 16 × 2 = 32 g/mol

Mass of O2 from the balanced equation = 13 × 32 = 416 g

Molar mass of CO2 = 12 + (16×2)

= 12 + 32

= 44 g/mol

Mass of CO2 from the balanced equation = 8 × 44 = 352 g

Summary:

From the balanced equation above,

116 g of butane reacted with 416 g of oxygen to produce 352 g of carbon dioxide.

Next, we shall determine the limiting reactant. This can be obtained as follow:

From the balanced equation above,

116 g of butane reacted with 416 g of oxygen.

Therefore, 34.29 g of butane will react with = (34.29 × 416) / 116 = 122.97 g of oxygen.

From the calculation made above, we can see clearly that only 122.97 g out of 165.7 g of oxygen reacted completely with 34.29 g of butane. Therefore, butane is the limiting reactant and oxygen is the excess reactant.

Next, we shall determine the theoretical yield of carbon dioxide.

In this case, we shall use the limiting reactant because it will give the maximum yield of carbon dioxide as all of it is used up in the reaction.

The limiting reactant is butane and the theoretical yield of carbon dioxide can be obtained as follow:

From the balanced equation above,

116 g of butane reacted to produce 352 g of carbon dioxide.

Therefore, 34.29 g of butane will react to produce = (34.29 × 352) / 116 = 104.05 g of carbon dioxide.

Therefore, the theoretical yield of carbon dioxide is 104.05 g

Finally, we shall determine the percentage yield of carbon dioxide as follow:

Actual yield of carbon dioxide = 51.9 g

Theoretical yield of carbon dioxide = 104.05 g

Percentage yield of carbon dioxide =?

Percentage yield = Actual yield /Theoretical yield × 100

Percentage yield of carbon dioxide = 51.9 / 104.05 × 100

Percentage yield of carbon dioxide = 49.9%

Answer:

1. 14 moles of NH3 were produced.

2. 7 moles of CO2 were produced.

3. 7 moles of H2O were produced.

Explanation:

We'll begin by writing a balanced equation for the decomposition of ammonium carbonate, (NH4)2CO3.

This is illustrated below:

(NH4)2CO3(s) —> NH3(g) + CO2(g) + H2O(g)

There are 2 atoms of N on the left side and 1 atom on the right side. It can be balance by putting 2 in front of NH3 as shown below:

(NH4)2CO3(s) —> 2NH3(g) + CO2(g) + H2O(g)

Now the equation is balanced.

From the balanced equation above,

1 mole of (NH4)2CO3 decompose to produce 2 moles of NH3, 1 mole of CO2 and 1 mole of H2O.

1. Determination of the number of mole of NH3 produced.

From the balanced equation above,

1 mole of (NH4)2CO3 decompose to produce 2 moles of NH3.

Therefore, 7 moles of (NH4)2CO3 will decompose to produce = 7 × 2 = 14 moles of NH3.

Therefore, 14 moles of NH3 were produced.

2. Determination of the number of mole CO2 produced.

From the balanced equation above,

1 mole of (NH4)2CO3 decompose to produce 1 mole of CO2.

Therefore, 7 moles of (NH4)2CO3 will also decompose to produce 7 moles of CO2.

Therefore, 7 moles of CO2 were produced.

3. Determination of the number of mole of H2O produced.

From the balanced equation above,

1 mole of (NH4)2CO3 decompose to produce 1 mole of H2O.

Therefore, 7 moles of (NH4)2CO3 will also decompose to produce 7 moles of H2O.

Therefore, 7 moles of H2O were produced.

Answer:

Solution

Explanation:

In science, the solution is a homogeneous mixture of two or more pure substances in proportional concentrations that can be continually varied up to what has been called the solubilization limit. The word solution is usually applicable to the fluid subatomic particle, but gaseous formulations are conceivable.