Which of the following substances has the lowest density?
A) A mass of 1.5 kg and a volume of 1.2 L
B) A mass of 25 g and a volume of 20 mL
C) A mass of 750 g and a volume of 70 dL
D) A mass of 5 mg and a volume of 25 UL (mcL)

Answer:

2.29 m.

Explanation:

The following data were obtained from the question:

Mass of KOH = 42.3 g

Molar mass of KOH = 56.11 g/mol

Mass of water = 329 g

Molality of KOH = ?

Next, we shall determine the number of mole in 42.3 g of KOH. This can be obtained as follow:

Mass of KOH = 42.3 g

Molar mass of KOH = 56.11 g/mol

Mole of KOH =?

Mole = mass /Molar mass

Mole of KOH = 42.3/56.11

Mole of KOH = 0.754 mole

Next, we shall convert 329 g of water to kilogram (kg). This can be obtained as follow:

1000 g = 1 kg

Therefore,

329 g = 329 g /1000 g × 1 kg

329 g = 0.329 kg

Therefore, 329 g of water is equivalent to 0.329 kg

Finally, we shall determine the molality of the KOH solution ad follow:

Molality is defined as the mole of solute per unit kilogram of solvent (water) i.e

Molality = mole/ mass (kg) of water

Mole of KOH = 0.754 mole.

Mass of water = 0.329 kg.

Molality = mole/ mass (kg) of water

Molality = 0.754/0.329

Molality = 2.29 m

Therefore, the molality of the KOH solution is 2.29 m.

Answer:

2.29

Explanation:

Answer:

A. Substance E

A. Substance C

A. Substance A  

Explanation:

Given that:

At 4 °C, Substance E has a vapor pressure of 86. torr and Substance F has a vapor pressure of 136. torr

Which has a higher boiling point?

A. Substance E

B. Substance F

C. Neither,EandF have the same boiling point

The vapor pressure varies inversely proportional to the boiling point.

[tex]\mathbf{vapor \ pressure \ \ \alpha \ \ \dfrac{1}{boiling \ point}}[/tex]

Therefore, the lower the vapor pressure, the higher the boiling point.

At 4°C, Substance E with a lower vapor pressure of 86. torr will have a higher boiling point from the given information.

2.

Recall that :

[tex]\mathbf{vapor \ pressure \ \ \alpha \ \ \dfrac{1}{enthalpy \ of \ vaporization}}[/tex]

therefore, the lower the enthalpy of vaporization, the higher the vapor pressure at any given temperature.

Given that:

Substance C has an enthalpy of vaporization smaller than that of substance D. Then, substance C has a higher vapor pressure.

3.

We've earlier said that:

The vapor pressure varies inversely proportional to the boiling point.

[tex]\mathbf{vapor \ pressure \ \ \alpha \ \ \dfrac{1}{boiling \ point}}[/tex]

Therefore, the lower the vapor pressure, the higher the boiling point.

As such, Substance A will have a higher boiling point.

Explanation:

You are suppose to use sig figs.

Answer:

Explanation:

The last number in a measured number is always an estimated digit.

Answer:

A. 2 protons, 2 electrons, and 1 neutron .

Answer:

A 2 protons, 2electrons,1 neutron

The heat from the oven heats up the metal pan, and the metal pan transfers the heat to the brownies.

Heat conduction is defined as the transfer of heat in an object from the area of hotter region to the area of cooler region through microscopic particles and movement of electrons within the body.

All the objects such as metal brownie pan that is capable of conducting heat is called the term thermal conductivity.

Examples of metals that are good conductors of heat include the following Gold, Silver, Copper, Aluminium, Iron.

Therefore, is can be concluded that the oven heats up the metal pan, and the metal pan transfers the heat to the brownies.

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Answer:

The mass of  Mg  and the mass of  Cl  in the sample

Explanation:

We have that the sample's is purity is simply the mass of Mg and the mass of Cl in the sample

From the Question we are told that

Mass of MgCl2 =5g

Therefore

What we need to  determine that the sample's is purity is simply the mass of Mg and the mass of Cl in the sample because

the mass of MgCl should be equal to mass of Mg and mas of Cl

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Answer:

2.6 g

Explanation:

Percent concentration = 5%

Volume of water = 50ml

Since 1ml of water = 1g of water

Mass of water= 50g

Let the mass of sucrose be x

Mass% = mass of solute/mass of solute + mass of solvent × 100

5= x/x+ 50 ×100

5/100 = x/x + 50

0.05 = x/x + 50

0.05(x + 50) = x

0.05x + 2.5 = x

2.5 = x - 0.05x

2.5 = 0.95x

x= 2.5/0.95

x=2.6 g

Answer:

It was just on a way and scienticts cant really "delete" it from galaxy so they descided accepting it and study it.

Explanation:

Answer:

In 1543 he further developed the heliocentric model. Copernicus was able to work out the arrangement of the known planets and how they move around the sun.

Explanation:

hope this helps:)

Answer:

B

Explanation:

Answer: 0.05

Explanation:Divide the length (1.5 cm) by the number of turns (30)

The direct proportion rule allows you to find that the correct answer for the result of the thickness of the copper wire is:

            0.05 cm

Copper is a strong material with which the cross section is constant, therefore the copper wire has a constant thickness, which is why when making a full turn it advances the same amount

When Jade wound thirty times (n = 30) it has the same diameter each time, therefore with a direct rule of proportions we can find the thickness of the wire.

If in 30 laps we have 1.5 cm, in one lap we have?

            [tex]x= 1 turn ( \frac{1.5 cm}{30 turn} )[/tex]  

            x = 0.05 cm

In conclusion using a direct rule of proportions we can that the correct answer for the result of the thickness of the copper wire is:

             0.05 cm

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Answer:

No because the sugar that went to it dissolved and the fruits are very blended in. It depends what smoothie it is because you can evaporate a strawberry smoothie and have only the strawberry mix instead of the water or milk.

Explanation:

Answer:

a)- Se, S, O

b)- Na, P, Cl

c)- S, Cl, F

d)- P, N, O

Explanation:

We can solve this problem by looking at the Periodic Table. In a group, electronegativity increases from bottom to top; whereas in periods it increases from left to right.

Thus, we order the elements from lower to higher electronegativity as follows:

a. Se, O, S ⇒ order: Se, S, O

Because they are all in the same group. Se is near the bottom, followed by S and O is at the top.

b. P, Na, Cl ⇒ order: Na, P, Cl

They are in the same period. Na is at the left, followed by P and Cl is nearest the right.

c. Cl, S, F ⇒ order: S, Cl, F

P and Cl are in the same period, and P is at the left, so it has the lowest electronegativity. F is in the same group of Cl, but at the top. F has the highest electronegativity.

d. O, P, N ⇒ order: P, N, O

N and P are in the same group, but P is at the bottom so it has the lower electronegativity. N and O are in the same period, but O is at the right, so it is the most electronegative.

Answer:

A.'C

Explanation:

Please answer my question

Answer:

the answer would be a

Explanation:

Answer:

ΔH = 87.8kJ

Explanation:

You can determine ΔH of a reaction from the sum of similar reactions (Hess's law). In the problem with the given ΔH:

1. C5H12(l)+8O2(g)→ 5CO2(g)+6H2O(g) ΔH= -3505.8 kJ

2. C(s)+O2(g)→CO2(g) ΔH= -393.5 kJ

3. 2H2(g)+O2(g)→ 2H2O(g) ΔH= -483.5 kJ

5 times 2. + 3 times 3:

5C(s) + 8O2(g) + 6H2(g) → 5CO2(g) + 6H2O(g)  

ΔH= 5*(-393.5 kJ) +  3*(-483.5 kJ) = -3418kJ

Now, this reaction - 1:

5C(s)+6H2(g) → C5H12(l) ΔH= -3418kJ - (-3505.8kJ)

Answer:

2.33×10¯¹⁶ g of forsterite

Explanation:

From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ atoms. This equally means that 1 mole of forsterite (Mg2SiO4) contains 6.02×10²³ atoms.

1 mole of forsterite (Mg2SiO4) = (24×2) + 28 + (16×4)

= 48 + 28 + 64

= 140 g

Finally, we shall determine the mass of forsterite that contains a million oxygen atoms.

140 g of forsterite (Mg2SiO4) contains 6.02×10²³ atoms.

Therefore, Xg of forsterite (Mg2SiO4) will contain 1×10⁶ atoms of oxygen i.e

Xg of forsterite (Mg2SiO4) =

(140 × 1×10⁶) /6.02×10²³

= 2.33×10¯¹⁶ g

Therefore, 2.33×10¯¹⁶ g of forsterite contains a million oxygen atoms..

The  mass of forsterite that contains a million oxygen atoms is 5.67 × 10^-17 g.

The chemical formula of forsterite is Mg2SiO4. Now, molar mass of forsterite is; 2(24) + 28 + 4(16) = 140 g/mol

Next, we have to obtain the number of oxygen atoms that are found in 1 mole of forsterite  as follows;

Number of oxygen atoms in 1 mole = 1 × 4 × 6.02 × 10^23 = 24.08  × 10^23 atoms

Now;

If 1 mole of forsterite  contains 24.08  × 10^23 atoms oxygen atoms

x moles of  forsterite  contains 1 × `10^6 atoms

x =  1 mole × 1 × `10^6 atoms/24.08  × 10^23 atoms

x = 4 × 10^-19 moles

Mass of forsterite that  contains  a million oxygen atoms = 4 × 10^-19 moles

×  140 g/mol = 5.67 × 10^-17 g

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Answer: She needs to divide the mass by the volume to find the density of the object.

Explanation:

Answer:

A. [tex]r=k[NO]^2[H_2][/tex]

B. [tex]k=0.121\frac{L^2}{mol^2*s}[/tex]

C. Second-order with respect to NO and first-order with respect to H₂

Explanation:

Hello,

In this case, for the reaction:

[tex]H_2O(g) + 2NO(g) \rightarrow N_2O + H_2O(g)[/tex]

The rate law is determined by writing the following hypothetical rate laws:

[tex]3.822x10^{-3}=k[0.3]^m[0.35]^n\\\\1.529x10^{-2}=k[0.6]^m[0.35]^n\\\\3.058x10^{-2}=k[0.6]^m[0.7]^n[/tex]

Whereas we can compute m as follows:

[tex]\frac{3.822x10^{-3}}{1.529x10^{-2}} =\frac{[0.3]^m[0.35]^n}{[0.6]^m[0.35]^n} \\\\0.25=(0.5)^m\\\\m=\frac{log(0.25)}{log(0.5)} \\\\m=2[/tex]

Therefore, the reaction is second-order with respect to NO. Thus, for hydrogen, we find n:

[tex]\frac{1.529x10^{-2}}{3.058x10^{-2}} =\frac{[0.6]^2[0.35]^n}{[0.6]^2[0.7]^n} \\\\0.5=(0.5)^n\\\\n=\frac{log(0.5)}{log(0.5)}\\ \\n=1[/tex]

A) Therefore, the reaction is first-order with respect to H₂. In such a way, we conclude that that the rate law is:

[tex]r=k[NO]^2[H_2][/tex]

B) Rate constant is computed from one kinetic data:

[tex]k=\frac{1.529x10^{-2}\frac{mol}{L*s} }{(0.6\frac{mol}{L} )^2(0.35\frac{mol}{L})}\\\\k=0.121\frac{L^2}{mol^2*s}[/tex]

C. As mentioned before, reaction is second-order with respect to NO and first-order with respect to H₂.

Best regards.

The order with respect to NO has been 2, while the order with respect to water has been 1.

The rate law has been the representation of the chemical concentration responsible for determining the rate of the reaction. The balanced chemical equation has been:

[tex]\rm H_2O\;+\;2\;NO\;\rightarrow\;N_2O\;+\;H_2O[/tex]

A. The rate equation for the reaction has been:

Rate = Rate constant [tex]\rm [H_2O]^m\;[NO]^n[/tex]

Where, m and n are the rate of the respective reactants.

The rate with respect to NO from the given data can be given as:

The ratio of Rate 1 to rate 2 with concentration of NO

[tex]\rm \dfrac{3.822\;\times\;10^-^3}{1.529\;\times\;10^-^2}[/tex] = [tex]\rm \dfrac{[0.3]^m\;[0.35]^n}{[0.6]^m\;[0.35]^n}[/tex]

m = 2

The rate of reaction with respect of NO has been 2.

The rate of reaction with water concentration has been:

[tex]\rm \dfrac{1.529\;\times\;10^-^2}{3.058\;\times\;10^-^2}[/tex] = [tex]\rm \dfrac{[0.6]^m\;[0.35]^n}{[0.6]^m\;[0.7]^n}[/tex]

n = 1

The rate of reaction with respect of water has been 1.

The rate law for reaction has been:

Rate = k [tex]\rm [H_2O]^1\;[NO]^2[/tex]

B. The rate constant can be given as:

Rate = 3.822 [tex]\rm \times\;10^-^3[/tex]

Concentration of NO = 0.6

Concentration of water = 0.35

The rate constant from the rate law can be given as:

3.822 [tex]\rm \times\;10^-^3[/tex] = k [tex]\rm [0.6]^2\;[0.35][/tex]

k = 0.121 [tex]\rm mol^-^2\;L^2\;s^-^1[/tex]

C. The order with respect to NO has been 2, while the order with respect to water has been 1.

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Answer:

For 1 hour 75w light bulb requires 270 kj  for burning

for 3 hours 75 w light bulb requires 270*3 = 810kj for burning

Explanation:

Answer:

the density increases

Explanation:

Coz high temperature makes water less dense. As water gets warmer, its molecules spread out, so it becomes less dense. As it gets colder, it becomes denser

Answer:

B) The molecular orbital formed is lower in energy than a hydrogen 1s atomic orbital.

Explanation:

When two atoms of hydrogen come close to each other , there is formation of molecular orbital . Due to overlap of 1 s orbital of one and 1 s orbital of another atom , two molecular orbitals are formed . One of these molecular orbital has energy less than 1 s atomic orbital . It is called 1 s sigma bonding molecular orbital . The other molecular orbital has energy more than 1 s atomic orbital . It is called antibonding molecular orbital . Two electrons occupy bonding sigma molecular orbital .

So , the statement that "the molecular orbital formed is lower in energy than a hydrogen 1s atomic orbital " is wrong .

Explanation:

Each carbon atom is covalently bonded to four other carbon atoms in diamond. A lot of energy is needed to separate the atoms. This is because covalent bonds are strong. This is the reason why diamond has a high melting point.

Answer:

1080 meters.

Explanation:

Answer:

d. I and II only

Explanation:

Evaporation is the breakaway of liquid molecules through the surface of a liquid, into the surrounding atmosphere in the form of a gas. Evaporation increases with temperature, since the molecules posses more kinetic energy to break through the liquid surface barrier at a higher temperature. Also, an increase in the surface area puts more of the molecules of the liquid close to the interface of the liquid and the surrounding atmosphere, increasing their chances of breaking away. An increase in the intermolecular forces between the molecules of the liquid will only decrease the rate of evaporation, since more energy will be required by the liquid molecules to break free from the bond between them and their neighboring molecules.

Answer: Sí

Explanation: ya que una mascota es inofensiva, pero para fotografiar a un animal salvaje, debes esperar pacientemente el momento perfecto