Why is it essential for a calorimetry to be an insulated (closed) system?


A. The heat exchange must originate from only the reaction (system).

B. Thermal insulation minimizes energy loses to the atmosphere.

C. A and B

D. None of the Above

Answers

Answer 1

Answer:

B.Thermal insulation minimizes energy loses to the atmosphere.

Explanation:

It is important because it helps to stop hit from transferring from the calorimeter to the environment. This would help to have an accurate measurement of the heat that was used in the chemical process. The greatest cause of error that happens in calorimetry is when heat is lost to the environment. To reduce this, you insulate the calorimeter and add a cover.


Related Questions

is magnetism, reactivity, and fluorescence used to identify minerals

Answers

yes it is used , hope this helps

Prepare a project report on various samples of  a) a mixture  b) a compound c) an element (metal or nonmetal)​

Answers

Answer:

Any substance that contains only one kind of an atom is known as an element. Because atoms cannot be created or destroyed in a chemical reaction, elements such as phosphorus (P4) or sulfur (S8) cannot be broken down into simpler substances by these reactions.

Example: Water decomposes into a mixture of hydrogen and oxygen when an electric current is passed through the liquid. Hydrogen and oxygen, on the other hand, cannot be decomposed into simpler substances. They are therefore the elementary, or simplest, chemical substances - elements.

Each element is represented by a unique symbol. The notation for each element can be found on the periodic table of elements.

The elements can be divided into three categories that have characteristic properties: metals, nonmetals, and semimetals. Most elements are metals, which are found on the left and toward the bottom of the periodic table. A handful of nonmetals are clustered in the upper right corner of the periodic table. The semimetals can be found along the dividing line between the metals and the nonmetals.

Explanation:

Which phrase correctly describes the molecular structure within a molecule?

Answers

Same molecular structure and same properties.

Molecular structure is three dimensional structure in which arrangement of atoms is placed.

The molecular structure of a compound determines the polarity and its reactivity.

The different states of matter solid, liquid and gas have different molecular structure and different properties from each other.

The molecular structure of a molecule will have same properties as of the entire molecule based on its state.

Learn more at https://brainly.com/question/24325752

Answer:

the location of atoms, groups, or ions relative to one another and the number, type, and location of covalent bonds

3. A typical peanut butter and jelly sandwich contains 360 kcal, of which 160
kcal comes from fat. Given 1 kcal = 4.2 kJ, how many J of fat would there be
in one PB&J sandwich?

Answers

Explanation:

here's the answer to your question

Calculate the amount of mole of iron produced from the reaction of 15.9 grams of iron oxide.
Fe2O3 + 3 H2 +2 Fe + 3 H2O

Answers

Answer:

0.19875

Explanation:

nFe2O3=0.099375

nFe=2nFe2O3=0.19875

Plz help I will give brainliest

Answers

Answer:

1. Fr

2. cl

3.H20

4.2 mole

5. 3

6. c

the element of group 1 hour reactive but those of group 18 are inert, why?​

Answers

Answer:

The noble gases (Group 18) are located in the far right of the periodic table and were previously referred to as the "inert gases" due to the fact that their filled valence shells (octets) make them extremely nonreactive.


Which of the following are held together by nonpolar covalent bonds?
The Periodic Table
A. Atoms of phosphorus (P) and chlorine (CI)
B. Atoms of chlorine (CI)
C. Atoms of chlorine (CI) and magnesium (Mg)
D. Atoms of magnesium (Mg)

Answers

Answer:

Answer: Atoms of chlorine (CI) and magnesium (Mg)

Answer: Atoms of chlorine (CI) and magnesium (Mg)is your answer

balance chemical reaction of oxalic acid with conc. sulphuric acid​

Answers

Answer:

Explanation: since oxalic acid is a weak acid it wont provide a strong acidic medium. So in order to provide a strong acidic medium dilute sulphuric acid is added.

In the reaction at Blood Falls, iron and oxygen combine to form iron oxide, which is called rust (water is also present). The reactants are
, and the product is

Answers

Answer:

The reactants for rust are iron ,water and oxygen while the products are hydrated iron oxide

Explanation:

4Fe+3O2+2H2O---->2Fe2O3.H2O

which state of matter expands most when heated​

Answers

Answer:

Gases expand the most upon heating because the intermolecular space is more than in solids or liquids.

Explanation:

hopes it helps

Gases
Gases expand the most upon heating because the intermolecular space is more than in solids or liquids.

Hope this helps

PLS MARK BRAINLY PLSSS

How many moles of oxygen are required to react completely with 5 mol C8H18?

Answers

Answer:

62.5 moles of O₂.

Explanation:

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

2C₈H₁₈ + 25O₂ —> 16CO₂ + 18H₂O

From the balanced equation above,

2 moles of C₈H₁₈ reacted with 25 moles of O₂.

Finally, we shall determine the number of mole of O₂ needed to react with 5 moles of C₈H₁₈. This can be obtained as shown below:

From the balanced equation above,

2 moles of C₈H₁₈ reacted with 25 moles of O₂.

Therefore, 5 moles of C₈H₁₈ will react with = (5 × 25) / 2 = 62.5 moles of O₂.

Thus, 62.5 moles of O₂ is needed for the reaction.

Can someone help me with this please

Answers

Answer:

.00305

Explanation:

There a 7 significant figures in the number because we know that leading zeroes are NOT counted. To round the number to have only 3 significant figures, we will need to round to the 5th decimal place. Remember the basic rules of rounding; 5 and up, round up, 4 and below, round down.

.00305346 → .00305

Best of Luck!

(Q008) Two physical properties of minerals both result in smooth, flat surfaces with specific angles between them. The first property is externally visible and is the result of how the mineral forms; the second is inherently internal and is the result of breaking a sample of the mineral. These properties are called

Answers

Answer: Crystal habit and cleavage.

Explanation:

When two physical properties of minerals both bring about smooth, flat surfaces that has specific angles between them.such that the first property is externally visible and is the result of how the mineral forms while the second property is internal and is the result of breaking a sample of the mineral, it should be noted that the properties are refered to as the crystal habit and cleavage.

It should be noted that the cleavage refers to the tendency of crystalline materials to be able to split along the structural planes.

How does the useable atoms of elements attain stability? Illustrate your answer with two example.

Answers

Answer:

An element which does not have two or eight electrons in its valence shell is unstable. It get stability by losing, gaining or sharing electron to complete noble gas electronic configuration. ... Elements attain stability by completing duplet or octet.

The boiling points of diatomic halogens are compared in the table.
Boiling Points of Diatomic
Halogens
Molecule
Boiling Point
F2
-188 °C
Cl2
-34 °C
Br2
59 °C
12
184°C
Which of the following statements best explains the trends in boiling points?
The atomic size increases down the group, and this decreases the strength of the intermolecular forces.
The total number of electrons decreases down the group, and this decreases the strength of the intermolecular forces.
The total number of electrons increases down the group, and this increases the strength of the intermolecular forces.
The chances of forming a permanent dipole increases down the group, and this increases the strength of the intermolecular forces.

Answers

Which of the following statements best explains the trends in boiling points?

A. The atomic size increases down the group, and this decreases the strength of the intermolecular forces.

                                           A is incorrect

B. The total number of electrons decreases down the group, and this decreases the strength of the intermolecular forces.

                                            B is incorrect

C. The total number of electrons increases down the group, and this increases the strength of the intermolecular forces.

                                             C is correct

D. The chances of forming a permanent dipole increases down the group, and this increases the strength of the intermolecular forces.

                                              D is incorrect

The boiling point increase down a group because the total number of electrons increases down the group, and this increases the strength of the intermolecular forces. Hence option C is correct.

What is boiling point?

Boiling point of a substance is the temperature at which the substance changes from its liquid state to vapour state. Boiling point of a molecule or compounds depends on the bond type, molecular weight, temperature and pressure.

For ionic compounds, boiling point will be higher since ionic bonds are stronger than covalent compounds. There is a periodic trend for the physical properties such as boiling point for elements in periodic table.

Down a group, the number of electrons increases and the atomic size also as well as the ionic character increases down a group . These two facts leads to higher intermolecular attraction, thus more temperature have to applied to weaken the bonds.

Higher temperature to be applied means the boiling point of the substance is higher. Therefore, boiling point down a group increases because of the higher intermolecular attraction as said in option C.

To find more about boiling point, refer the link below:

https://brainly.com/question/2153588

#SPJ1

Which factor would speed up a chemical reaction? (Choose all that apply)
Decreasing particle size
Increasing the temperature
Decreasing the temperature
Increasing particle size

Answers

Answer:

Increasing the temperature

Increasing particle size

Explanation:

Increasing the temperature allows for particles and molecules to move faster (because there is an increase in energy) and allows for more collisions.

∴ Increasing the temperature would be an answer.

Increasing the particle size allows for more surface area and a greater chance for particles to collide with each other.

∴ Increasing particle size would be an answer.

Topic: AP Chemistry

Unit: Kinetics

Hạt nhân nguyên tử được tạo bởi

Answers

Answer:

The FitnessGram™ Pacer Test is a multistage aerobic capacity test that progressively gets more difficult as it continues. The 20 meter pacer test will begin in 30 seconds. Line up at the start. The running speed starts slowly, but gets faster each minute after you hear this signal. [beep] A single lap should be completed each time you hear this sound. [ding] Remember to run in a straight line, and run as long as possible. The second time you fail to complete a lap before the sound, your test is over.

Two glasses labeled A and B had equal amounts of water. Ted heated the water in one of the glasses. He then put two drops of food coloring into each of the two glasses. The table shows the time taken by the food coloring in the two glasses to spread out.

Which of the following statements is correct?

A - The water in Glass B was heated; therefore, the particles in Glass B have greater kinetic energy and move faster.
B - The water in Glass A was heated; therefore, the particles in Glass A have greater kinetic energy and move faster.
C - The water in Glass B was heated; therefore, the particles in Glass B move slower.
D - The water in Glass A was heated; therefore, the particles in Glass A move slower.

Answers

Answer:

The answer is A: The water in Glass B was heated; therefore, the particles in Glass B have greater kinetic energy and move faster.

Explanation:

Think about it, if you boil water, whatever you put in the water is going to move around faster than if you put something in standing water.

(PLEASE mark Brainliest!)

The water in Glass B was heated; therefore, the particles in Glass B have greater kinetic energy and move faster. The correct answer is A.

What is food coloring?

Food coloring, or color additive, is any dye, pigment, or substance that imparts color when it is added to food or drink.

The food coloring we add to the water is pushed around by the water molecules. Since the molecules in warm water move around faster, the food coloring spreads out quicker in warm water than in cold water.

From the table, we can say that the water in glass B was heated by Ted and the molecules of food coloring spread out quickly in warm water and they have greater kinetic energy and move faster.

On the other hand, in glass A, the water is cold, so food coloring will not dissolve quickly.

Therefore, The water in Glass B was heated; therefore, the particles in Glass B have greater kinetic energy and move faster. The correct answer is A.

To learn more about food coloring, click here:

https://brainly.com/question/6750847

CaCO3 + 2HCl > CaCl2 + CO₂ + H₂O​

Answers

Explanation:

This reaction is also known as double decomposition reaction.

HCl + CaCO3 + MgCO3 → H2O + H2 + CO2 + CaCl2 + MgCl2

Can someone tell me the advantages and disadvantages of Ceramics? I need scientific, good and clear points! :)

Answers

Advantage
Good conductor of heat
Extreme hard

Disadvantage
Zero ductility
Brittle in nature

Predict the approximate Ksp of Cuz(AsO4)2 based on the measured potential of Cell 7. Use the equation given in the Background.

a. 1 x 10^-35

b. 4 x 10^14

c. 5 x 10^-17

d. 2 x 10^-21

Answers

Answer:

a. 1 x 10^-35

Explanation:

The correct compound given is: [tex]\mathsf{Cu_3(AsO_4)}_2[/tex]

To predict the approximate Ksp value of the given compound, we will need to express the oxidation-reduction half-reaction of the compound and its dissociation, then, we will use the Nernst equation to determine the approximate Ksp value.

To start with the reduction half-reaction:

[tex]\mathsf{Cu_3(AsO_4)_{2}(s) + 6e^- \to 2As O_{4}^{3-}_{(aq)}+3Cu(s) }[/tex]

The oxidation half-reaction is:

[tex]\mathsf{3Cu(s) \to 3CU^{2+}_{(aq)} + 6e^-}[/tex]

The overall cell reaction now is:

[tex]\mathsf{Cu_3(AsO_4)_{2}(s) \to 3Cu^+ (aq) + 2As O_{4}^{3-}_{(aq)} }[/tex]

From the reduction half-reduction, the number of moles of electrons (n) transferred is 6 moles.

By applying the Nernst equation:

[tex]\mathsf{E_{cell} = E^0_{cell} -\dfrac{0.0591V}{n}log [Cu^{2+}]^3[AsO_4^{3-}]^2 }[/tex]

At standard conditions;

The standard cell potential [tex]\mathsf{E^0_{cell} = -0.342 \ V}[/tex]

and [tex]\mathsf{E_{cell} = 0 \ V}[/tex] since it is at equilibrium.

[tex]\mathsf{0 = -0.342 -\dfrac{0.0591V}{6}log [Cu^{2+}]^3[AsO_4^{3-}]^2 } \\ \\ \\ \mathsf{0.342 = -\dfrac{0.0591V}{6}log [Cu^{2+}]^3[AsO_4^{3-}]^2 }[/tex]

[tex]\mathsf{log [Cu^{2+}]^3[AsO_4^{3-}]^2 = \dfrac{-(0.342)*6}{0.0591 }}[/tex]

[tex]\mathsf{log [Cu^{2+}]^3[AsO_4^{3-}]^2 = -34.7}[/tex]

[tex]\mathsf{log [Cu^{2+}]^3[AsO_4^{3-}]^2 \simeq -35}[/tex]

[tex]\mathsf{[Cu^{2+}]^3[AsO_4^{3-}]^2 = 10^{-35}}[/tex]

[tex]\mathbf{K_{sp} = [Cu^{2+}]^3[AsO_4^{3-}]^2 = 1\times 10^{-35}}[/tex]

Urgent please help
A.Ca
B. CaO
C.CO

Answers

B
ionic compound formed with metal and non metal
ca is metal
and O is non metal

please help me with this question.
ps: kindly include a drawing.​

Answers

Answer:

gallium has orthorhombic and forms ionic bonds with metals

Explanation:

You mix the sample discussed in the previous two questions with another sample, which you know to be pure acetylsalicylic acid. You grind the mixture thoroughly with a mortar and pestle, and do a melting point determination on the mixed product. You now observe melting over a range of 127 to 133 C. Now what conclusions can you reach regarding the original product

Answers

Answer:

Having high melting point.

Explanation:

The original product has high melting point as compared to the mixture product because in the original product, the element is present in its pure state and we know that pure substances have high melting point as compared to mixture substances due to the presence of strong intercellular forces between them which is hard to break so that's why we can say that the original product has high melting point.

A block of dry ice (-40°C) is placed in contact with an ice cube (-10°C).
What will happen, assuming no chemical reactions occur?
O Heat will flow from the ice cube to the dry ice.
O Heat will flow from the dry ice to the ice cube.
O There is no way to tell without a thermometer
O No heat will flow.​

Answers

Explanation:

Answer is that : no heat will flow

Answer:

Heat will flow from the ice cube to the dry ice

Explanation:

An aqueous solution contains
32.7% KCl (weight/weight %).

How many grams of water (H20) are contained in 100 g of this solution?

Answers

Answer:

67.3g

Explanation:

%(w/w) = mass of solute/total mass of solution × 100

According to this question, an aqueous solution contains 32.7% KCl (w/w%). Firstly, we find the mass of the solute (KCl) as follows, if the mass of solution is 100g:

32.7 = mass of solute/100 × 100

mass of solute (KCl) = 32.7g

Mass of solution = mass of solvent (water) + mass of solute (KCl)

100g = x + 32.7g

x = 100 - 32.7

x = 67.3

Hence, the mass of water contained in the 100g solution is 67.3g.

What are the standard temperature and pressure conditions enthalpy is usually measured under

Answers

Answer:

temperature must be 273 Kelvin (0°C)

pressure must be 1 atm

Determine the empirical formula for compounds that have the following analyses. a. 28.4% copper, 71.6% bromine b. 39.0% potassium, 12.0% carbon, 1.01% hydrogen, and 47.9% oxygen c. 77.3% silver, 7.4% phosphorus, 15.3% oxygen d. 0.57% hydrogen, 72.1% iodine, 27.3% oxygen

Answers

Answer:

See explanation

Explanation:

Cu- 28.4/63.5, Br- 71.6/80

Cu- 0.447/0.447, Br- 0.895/0.447

Cu- 1, Br - 2

Empirical formula = CuBr2

b)

K- 39.0/39, C-12.0/12, H- 1.01/1, O- 47.9/16

K= 1, C-1, H- 1. O-3

Empirical formula= KHCO3

c)

Ag- 77.3/108, P-7.4/31, O-15.3/16

Ag-0.716/0.239, P- 0.239/0.239, O-0.956/0.239

Ag-3, P-1, O-4

Empirical formula= Ag3PO4

d)

H-0.57/1, I- 72.1/127, O-27.3/16

H- 0.57/0.57, I- 0.57/0.57, O-1.71/0.57

H-1, I-1, O- 3

Empirical formula= HIO3

Which of the following elements would you expect to be most reactive, based
on the number of valence electrons it has?

Answers

Answer:

C. Lithium

Explanation:

This image describes the trend in reactivity. Group 1 metals are always the most reactive so yeah :)

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