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The heat released : b. -7.34 x 10² kJ

Given

1.65 mol NaOH

The molar heat of solution of NaOH is -445.1 kJ/mol

Required

Heat released

Solution

ΔH solution = Q : n

ΔH solution = enthalpy of solution(-=exothermic, +=endothermic)

Q = heat released/absorbed

n = moles of solute

Input the value :

Q = ΔH solution x n

Q = -445.1 kj/mol x 1.65 mol

Q = -734.415 kJ

Answer:

Im pretty sure its B

Sorry if Im wrong

Explanation:

Have a wonderful day!!!<3

Answer:

The only answer that could apply to a gas is A

Explanation:

Answer:

1.17 M

Explanation:

Step 1: Write the balanced equation

N₂ + 3 H₂ ⇒ 2 NH₃

Step 2: Calculate the rate of disappearance of H₂

We will use the following expression.

rH₂ = - Δ[H₂]/t = - (0.25 M - 0.50 M)/44 s = 0.0057 M/s

Step 3: Calculate the rate of disappearance of N₂

The molar ratio of N₂ to H₂ is 1:3.

0.0057 mol H₂/L.s × 1 mol N₂/3 mol H₂ = 0.0019 mol N₂/L.s

Step 4: Calculate the final concentration of N₂

We will use the following expression.

[N₂] = [N₂]₀ - rN₂ × t

[N₂] = 1.25 mol/L - 0.0019 mol/L.s × 44 s

[N₂] = 1.17 M

Answer:

An ecosystem is a community or group of living organisms that live in and interact with each other in a specific environment.

Explanation:

That's the most straight forward explanation I could come up with

Answer:

Egypt

Explanation:

Hi again

Answer:

27.4°C

Explanation:

Using the equation:

Q = m*C*T

Where Q is heat added,

m the mass of water

C specific heat of water (4.18J/g°C)

And T the increase in temperature

We can solve for the increase in temperature and thus, the final temperature of water:

Q = 88200J; m = 6500g:

88200J = 6500g*4.18J/g°C*T

3.2°C = T = increase in temperature

Final temperature is:

24.2°C + 3.2°C =

Answer:

56 J

Explanation:

Step 1: Given data

Step 2: Calculate the work (w) done on the object

We can find the work done on the object using the following expression.

w = F × d × cosθ

where

θ is the angle between F and d

Since F and d occur in the same direction, θ = 0° and cosθ = 1. Then,

w = F × d × 1

w = F × d

w = 7 N × 8 m = 56 J

Answer:

endothermic reaction

Explanation:

When Elsa from Frozen freezes things, it is an example of an endothermic chemical reaction.

An endothermic involves a reaction in which heat is absorbed from the surrounding. Hence the surrounding becomes colder at the end of the the change.

So, Elsa draws heat from the environment and this causes the environment to be colder and things that are in contact with her.

Answer: Sol:-

Data provided in the question is :-

Atomic mass of isotope -1 = 64 amu

Atomic mass of isotope -2 = 66 amu

Atomic mass of isotope -3 = 67 amu

Atomic mass of isotope -4 = 68 amu

Atomic mass of isotope - 5 = 70 amu

Percentage abundace of isotope - 1 = 48.89 %

Percentage abundance of isotope -2 = 27.81 %

Percentage abundance of isotope - 3 = 4.11%

Percentage abundance of isotope-4 = 18.57%

Percentage abundance of isotope - 5 = 0.62 %

Formula used :-

Average atomic mass of an element =[ {(atomic mass of isotope-1 * percentage abundance of isotope-1) + ( atomic mass of isotope-2 * percentage abundance of isotope -2) + ( atomic mass of isotope -3 * percantege abundance of isotope-3 ) + ( atomic mass of isotope-4 * percentage abundance of isotope-4) + (atomic mass of isotope-5 * percentage abundance of isotope-5)} / 100]

Calculation :-

Put all the value in the formula :-

Average atomic mass of an element = [{(64 * 48.89) + (66 * 27.81) + (67 * 4.11) + (68 * 18.57) + (70 * 0.62)} / 100] amu

= [{(3128.96) + (1835.46) +(257.37) + (1262.76) + (43.4)} / 100] amu

= {(6528.04) / 100} amu

= 65.2804 amu

Average atomic mass of an element is = 65.2804 amu

Then this mass is approximatly equal to atomic mass of zinc so this element would be zinc

atomic mass of zinc = 65.38 \approx 65.2804 amu

Answer:

Acidic solution used to clean a crucible

Explanation:

This liquid dissolves alcoholic solvents such as crucible, that is why it was selected as the ideal for cleaning.

Although it would be ideal to know in detail which chemical compound is the one you want to clean so that the cleaning technique has better effectiveness.

WASTE CONTAINER refers to the solvent used to rinse chemicals out of a beaker, and it also refers to the acid solution used to clean a crucible. Water used to rinse the detergent out of a flask refer to the SINK.

In conclusion, WASTE CONTAINER refers to the solvent used to rinse chemicals out of a beaker, and it also refers to the acid solution used to clean a crucible. Water used to rinse the detergent out of a flask refer to the SINK.

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Answer:

116.78 grams.

Explanation:

1 mol of Strontium (Sr) = 87.62 grams

1.38 mol of Strontium = x

Cross Multiply

1 * x = 1.38 * 87.62

x = 116.78  grams

The  uncertainties  of  the  delta  measurements  and  the  uncertainty  of  the  atomic  weight  derivedfrom  the  best  measurement  of  isotopic  abundances  constrain  the  number  of  significant  figures  in  theatomic-weight values of the upper and lower bounds. For carbon, the fifth digit after the decimal pointis uncertain because of the uncertainty value of 0.000 027. Therefore, the number of significant digitsin the atomic-weight value is reduced to four figures after the decimal point. The Commission may rec-ommend  additional  conservatism  and  reduce  the  number  of  significant  figures  further.  For  the  lowerbound of carbon, 12.009 635 is truncated to 12.0096. For an upper bound, the trailing digit is increasedto ensure the atomic-weight interval encompasses the atomic-weight values of all normal materials. Inthe case of carbon, the upper bound is adjusted from 12.011 532 to 12.0116 to express four digits afterthe decimal point. The lower and upper bounds are evaluated so that the number of significant digits ineach  is  identical.  If  a  value  ends  with  a  zero,  it  may  need  to  be  included  in  the  value  to  express  therequired number of digits. The following are examples of lower and upper atomic-weight bounds foroxygen that could be published by the Commission in its various tables.

---------------------------

Extracted from" Atomic weights of the elements 2009 (IUPAC Technical Report)"

Answer:

b

Explanation:

Answer:

25 mM Tris HCl and 0.1% w/v SDS

Explanation:

A 10X solution is ten times more concentrated than a 1X solution. The stock solution is generally more concentrated (10X) and for its use, a dilution is required. Thus, to prepare a buffer 1X from a 10X buffer, you have to perform a dilution in a factor of 10 (1 volume of 10X solution is taken and mixed with 9 volumes of water). In consequence, all the concentrations of the components are diluted 10 times. To calculate the final concentration of each component in the 1X solution, we simply divide the concentration into 10:

(250 mM Tris HCl)/10 = 25 mM Tris HCl

(1.92 M glycine)/10 = 0.192 M glycine

(1% w/v SDS)/10 = 0.1% w/v SDS

Therefore the final concentrations of Tris and SDS are 25 mM and 0.1% w/v, respectively.

Answer:

Substance B, boiling point of 105 °C

Explanation:

Non volatile substances have high boiling points

Answer:

Electron (e-)

Explanation:

An electron is just one of the fundamental particles

Answer:heyyyy

Explanation:

Answer:

Liquid

Explanation:

A gray element that borders on the zigzag line of the periodic table, is ductile and malleable, but is not a very good conductor of heat or electricity is known as metalloid. The correct option is option C.

In chemistry, a periodic table is an orderly arrangement of each of the chemical elements along order of atomic number is, the total amount of protons inside the atomic nucleus.

Whenever the chemical elements stand grouped in this manner, there is a recurrent pattern in their characteristics known as the "periodic law," in which elements within a single column (group) exhibit comparable qualities. A gray element that borders on the zigzag line of the periodic table, is ductile and malleable, but is not a very good conductor of heat or electricity is known as metalloid.

Therefore, the correct option is option C.

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Answer:

1.62

Explanation:

From the given information:

number of moles of benzamide  [tex]=\dfrac{70.4 \ g}{121.14 \ g/mol}[/tex]

= 0.58 mole

The molality = [tex]\dfrac{mass \ of \ solute (i.e. \ benzamide )}{mass \ of \ solvent }[/tex]

[tex]= \dfrac{0.58 }{0.85 }[/tex]

= 0.6837

Using the formula:

[tex]\mathbf {dT = l \times k_f \times m}[/tex]

where;

dT = freezing point = 27

l = Van't Hoff factor = 1

kf = freezing constant of the solvent

∴

2.7 °C = 1 × kf ×  0.6837 m

kf = 2.7 °C/ 0.6837m

kf = 3.949 °C/m

number of moles of NH4Cl = [tex]\dfrac{70.4 \ g}{53.491 \ g /mol}[/tex]

= 1.316 mol

The molality = [tex]\dfrac{1.316 \ mol}{0.85 \ kg}[/tex]

= 1.5484

Thus;

the above kf value is used in determining the  Van't Hoff factor for  NH4Cl

i.e.

9.9 = l × 3.949 × 1.5484 m

[tex]l = \dfrac{9.9}{3.949 \times 1.5484 \ m}[/tex]

l = 1.62

Answer:

The soil has a percentage of water by mass of 27.8 %.

Explanation:

Keeping in mind that

we can calculate the mass of water:

We can then calculate the mass percentage of water in the soil:

Answer:

Carbon and oxygen are chemically bonded in it.

Explanation:

The other answer choices do not apply for compounds, but rather for mixtures instead.

Answer:

B. The microscope paved the way

Explanation:

This section from the article, "History of the Cell: Discovering the Cell", that emphasizes the role of technological development in the discovery of cells, is the subheading, "The microscope paved the way". In this subheading, the author narrated how Robert Hooke improved the existing microscope, and was able to discover the cell through it.

Further improvement of the simple microscope by Antonie van Leeuwenhoek led to the discovery of bacteria and protozoa.

Answer:

all of the above

Explanation:

now I will bless you with this-

Answer:

A 400,000 kg object and a 100,000,000kg object

Explanation:

The objects with the most mass between them will have the greatest gravitational attraction.

This is why the last option is the right choice.

The reason for this is based on the Newton's law of universal gravitation which states that:

 "the gravitational force of attraction between two bodies is directly proportional to the product of their masses and inversely proportional to the square of the distance between them".

So, the more the mass, the greater the gravitational attraction between two bodies.

Answer:

The molarity of the acid, H₂SO₄ is 3.57 M

Explanation:

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

H₂SO₄ + 2NaOH —> Na₂SO₄ + 2H₂O

From the balanced equation above,

Mole ratio of the acid, H₂SO₄ (nₐ) = 1

Mole ratio of the base, NaOH (n₆) = 2

Finally, we shall determine the molarity of the acid, H₂SO₄. This can be obtained as follow:

Volume of base, NaOH (V₆) = 38.70 cm³

Molarity of base, NaOH (M₆) = 1.90M

Volume of acid, H₂SO₄ (Vₐ) = 10.30 cm³

Molarity of acid, H₂SO₄ (Mₐ) =?

MₐVₐ / M₆V₆ = nₐ/n₆

Mₐ × 10.3 / 1.9 × 38.70 = 1/2

Mₐ × 10.3 / 73.53 = 1/2

Cross multiply

Mₐ × 10.3 × 2 = 73.53 × 1

Mₐ × 20.6 = 73.53

Divide both side by 20.6

Mₐ = 73.53 / 20.6

Mₐ = 3.57 M

Thus, the molarity of the acid, H₂SO₄ is 3.57 M

Answer:

b

Explanation:

it is not c because water expands when it freezes.

Answer:

Q =  57934.8 J

Explanation:

Given data:

Mass of water = 180.0 g

Initial temperature = 19°C

Fina temperature = 96°C

Specific heat capacity of water = 4.18 J/g.°C

Heat absorbed = ?

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT = 96°C - 19°C

ΔT = 77°C

Q = 180.0 g×4.18 J/g.°C×77°C

Q =  57934.8 J

Answer:

fluorine

Explanation:

it has the highest electronegativity in the group and in the periodic table

Answer:

See explanation

Explanation:

A substance is classified as polar, nonpolar or ionic based on its behavior.

For the substances identified, there was no difficult in identifying each as  polar, nonpolar, or ionic because since it was quite to easy identify where each belongs by looking out for whether it mixes or dissolves in our experiment.

Every substance in the experiment either mixed or dissolved during the  experiment.

Answer:

See explanation and image attached

Explanation:

Often times, there is a need for a three dimensional representation of a molecule on paper. These three dimensional representations give us an idea of what the molecule really looks like if we were to be looking at it physically.

In order to make a three dimensional representation, we use wedged and dashed bonds. The wedged bonds are coming out of the plane of the paper towards you while the dashed bonds are going into the plane of the paper away from you.

In the image attached, you will find the three dimensional representation of the methane molecule.