270kJ are needed to keep a 75 watt light bulb burning for 1 hour. How many kilocalories are needed to burn this light bulb for 3 hours?

Answer:

1080 meters.

Explanation:

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:

The answer is D a beaker

Explanation:

Hope this helps :D

Answer:

14.6 %

Explanation:

Step 1: Given data

Mass of sodium chloride (solute): 6.09 g

Mass of water (solvent): 35.50 g

Step 2: Calculate the mass of solution

We will use the following expression.

m(solution) = m(solute) + m(solvent)

m(solution) = 6.09 g + 35.50 g

m(solution) = 41.59 g

Step 3: Calculate the percent by mass of the salt

We will use the following expression.

%w/w = mass of NaCl / mass of solution × 100%

%w/w = 6.09 g / 41.59 g × 100%

%w/w = 14.6 %

Answer:

After 26.0s, the concentration of HI decreases from 0.310M to 0.0558M.

Explanation:

Based on the reaction of the problem, you have as general kinetic law for a first-order reaction:

ln[HI] = -kt + ln [HI]₀

Where [HI] is actual concentration after time t,

k is rate constant

and [HI]₀ is initial concentration of the reactant.

Initial concentration of HI is 0.310M,

K is 0.0660s⁻¹,

And the actual concentration is 0.0558M:

ln[HI] = -kt + ln [HI]₀

ln[0.0558M] = -0.0660s⁻¹*t + ln [ 0.310M]

-1.7148 = -0.0660s⁻¹*t

26.0s = t

Answer:

a. 7.528x10²² atoms Ti

b. 7.528x10²² atoms Ti

c. 1.5055x10²³ atoms Ti

d. 2.258x10²³ atoms Ti

Explanation:

Using the molecular formula of the structures, we can determine the moles of titanium in 0.125 moles of each compound. With moles of titanium we can convert these to atoms using Avogadro's number as follows:

a. FeTiO₃: 1 mole of Ti per mole of FeTiO₃.

Moles of Ti are 0.125 moles. Atoms are:

0.125 moles Ti * (6.022x10²³ atoms / 1 mole) =

b. Titanium (IV) chloride = TiCl₄: 1 mole of Ti per mole of TiCl₄.

Moles of Ti are 0.125 moles. Atoms are:

0.125 moles Ti * (6.022x10²³ atoms / 1 mole) =

c. Ti₂O₃: 2 moles of Ti per mole of Ti₂O₃.

Moles of Ti are 2*0.125 moles = 0.25 moles. Atoms are:

0.25 moles Ti * (6.022x10²³ atoms / 1 mole) =

a. Ti₃O₅: 3 mole of Ti per mole of Ti₃O₅.

Moles of Ti are 3*0.125 moles = 0.375 moles of Ti. Atoms are:

0.375 moles Ti * (6.022x10²³ atoms / 1 mole) =

From the formula for calculating number of atoms, the number of atoms of Ti in 0.125 moles of the compounds FeTiO₃, TiCl₄, Ti₂O₃, Ti₃O₅ are 7.528 * 10²² atoms Ti, 7.528 x 10²² atoms Ti, 1.5055 * 10²³ atoms Ti and 2.258 * 10²³ atoms Ti respectively.

The number of atoms present in a substance is calculated using the formula:

Moles of Titanium in the compounds:

a. FeTiO₃ contains 1 mole of Ti per mole of FeTiO₃.

Moles of Ti are 0.125 moles.

number of atoms = 0.125 * 6.022x10²³ atoms

number of atoms = 7.528 * 10²² atoms Ti

b. 1 mole of Titanium (IV) chloride TiCl₄ contains 1 mole of Ti per mole of TiCl₄.

Moles of Ti are 0.125 moles.

Atoms of titanium = 0.125 * 6.022x10²³ atoms / 1 mole)

number of atoms = 7.528 x 10²² atoms Ti

c. 1 mole of Ti₂O₃ contains 2 moles of Ti per mole of Ti₂O₃.

Moles of Ti are 2 * 0.125 moles = 0.25 moles

number of atoms = 0.25 * 6.022x10²³ atoms

number of atoms = 1.5055 * 10²³ atoms Ti

d.1 mole of Ti₃O₅ contains 3 mole of Ti per mole of Ti₃O₅.

Moles of Ti are 3 * 0.125 moles = 0.375 moles of Ti.

number of atoms = 0.375  * 6.022x10²³ atoms

number of atoms = 2.258 * 10²³ atoms Ti

Therefore, the number of atoms of Ti in 0.125 moles of the compounds FeTiO₃, TiCl₄, Ti₂O₃, Ti₃O₅ are 7.528 * 10²² atoms Ti, 7.528 x 10²² atoms Ti, 1.5055 * 10²³ atoms Ti and 2.258 * 10²³ atoms Ti respectively.

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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:

B

Explanation:

Answer:

a. pH = 4.56

b. Change in pH = 0.85

c. Change in pH = 5.4

Explanation:

a. The pKa of lactic buffer is: 3.86.

Using Henderson-Hasselbalch formula for the lactic buffer:

pH = 3.86 + log [Lactate] / [Lactic acid]

Where [] is molarity of each compound but could be taken as moles

Replacing:

pH = 3.86 + log [0.050 moles] / [0.010 moles]

pH = 4.56

b. The HCl added reacts with Lactate producing lactic acid. Moles of HCl are:

5x10⁻³L * (0.5mol /L) = 0.025 moles HCl

Moles of lactate: 0.050moles - 0.025 moles = 0.025 moles

Moles lactic acid: 0.010 moles + 0.025 moles = 0.035 moles

pH = 3.86 + log [0.025 moles] / [0.035 moles]

pH = 3.71

Change in pH = 4.56 - 3.71 = 0.85

c. 1L of pure water has a pH of 7. 0.025 moles of HCl = 0.025 moles H⁺ in 1.005L:

0.025 mol / 1.005L = 0.0249M = [H⁺]

As pH = -log [H⁺]

pH = 1.6

Change in pH = 7.0 - 1.6 = 5.4

Answer:

A.'C

Explanation:

Please answer my question

Answer:

the answer would be a

Explanation:

Answer:

Explanation:

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

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.

Answer:

A property that changes if the amount of substance changes

Explanation:

An extensive property is a property that depends on the amount of matter in a sample.

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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#SPJ1

Answer:

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

Answer:

A 2 protons, 2electrons,1 neutron

Explanation:

You are suppose to use sig figs.

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:

Define a problem, form a hypothesis, gather experimental data, form a conclusion

Answer:

Make observations, gather experimental data, form a conclusion, state a problem Define a problem, form a hypothesis, gather experimental data, form a conclusion.

Explanation:

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:

ΔH = 14,7kJ/mol

Explanation:

It is possible to make algebraic sum of several chemical process to obtain enthalpy of a determined reaction (Hess's law).

Sublimation of iodine is (Transition from solid to gas):

I₂(s) → I₂(g) ΔH = 60.2kJ/mol

Vaporization of iodine (From liquid to gas):

I₂(l) → I₂(g) ΔH = 45.5kJ/mol

Fusion of iodine (From solid to liquid can be obtained subtracting the sublimation process - Vaporization process:

I₂(s) → I₂(g) ΔH = 60.2kJ/mol

I₂(g) → I₂(l) ΔH = -45.5kJ/mol

I₂(s) → I₂(l) ΔH = 60.2kJ/mol - 45.5kJ/mol

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:

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:

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.

For more information about the rate of reaction, refer to the link:

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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:

1.001

Explanation:

The Significant Figures are 1 0 0 1, This answer has 4 Significant figures, while the other three have only 2 significant figures

Answer:

See explanation

Explanation:

To write a verbal sentence to represent an equation, we must look at the equation closely in order to capture its essence.

For this equation, 3y= 4y^3, we can write it in words as:

Three multiplied by y is equal to four multiplied by y raised to power three.