How do I answer the question in bold? Thank you!

Answer:

mineral oil; close to; slowly turn

Explanation:

Temperature can be defined as a measure of the degree of coldness or hotness of a physical object. It is measured with a thermometer and its units are Celsius (°C), Kelvin (K) and Fahrenheit (°F).

Generally, temperature measures the average kinetic energy of particles in a particular substance.

A thermometer can be defined as a device used for measuring the temperature (degree of hotness or coldness) of a body or substance is. It is a thin glass having a bulb on one of its end and typically contains either colored alcohol or mercury.

A thermometer adapter is used with a temperature probe in the distillation process, in order to determine readings.

To insert a thermometer into an adapter, use mineral oil to prepare or make suitable the thermometer. Then, hold the thermometer close to the adapter and slowly turn the thermometer into the adapter.

Answer:

Changes of state occur at segment

✔ B–C

and segment

✔ D–E

Explanation:

got it right on edge :)

The amount of energy added to the ice between Point A and Point D is approximately 25 kJ.

To calculate the amount of energy added to the ice between Point A and Point D, we need to consider the different stages of the heating curve.

Heating the ice from -20°C to 0°C:

The energy required to raise the temperature of the ice can be calculated using the specific heat of ice (2.10 J/(g·°C)) and the mass of the ice (60.0 g). The temperature change is from -20°C to 0°C, which is a total of 20 degrees.

Energy = mass × specific heat × temperature change

Energy = 60.0 g × 2.10 J/(g·°C) × 20°C

Energy = 2520 J

Melting the ice at 0°C:

The energy required to melt the ice can be calculated using the latent heat of fusion of ice (333.4 J/g) and the mass of the ice (60.0 g).

Energy = mass × latent heat of fusion

Energy = 60.0 g × 333.4 J/g

Energy = 20,004 J

Heating the water from 0°C to 15°C:

The energy required to raise the temperature of the water can be calculated using the specific heat of water (4.18 J/(g·°C)) and the mass of the water (60.0 g). The temperature change is from 0°C to 15°C, which is a total of 15 degrees.

Energy = mass × specific heat × temperature change

Energy = 60.0 g × 4.18 J/(g·°C) × 15°C

Energy = 3753 J

The total energy added to the ice between Point A and Point D is the sum of the energy calculated in each step:

Total Energy = Energy (Heating ice) + Energy (Melting ice) + Energy (Heating water)

Total Energy = 2520 J + 20,004 J + 3753 J

Total Energy = 25,277 J

Converting this energy to kilojoules (kJ):

Total Energy = 25,277 J ÷ 1000

Total Energy = 25.277 kJ

Therefore, the amount of energy added to the ice between Point A and Point D is approximately 25 kJ.

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Answer:

3.65 g of cyclohexene

Explanation:

Cyclohexanol + phosphoric acid ----> cyclohexene

The reaction is 1:1 hence the limiting reactant is phosphoric acid.

Hence,

1 mole of phosphoric acid yields 1 mole of cyclohexene

0.0444 moles of phosphoric acid yields 0.0444 moles of cyclohexene

Theoretical yield = number of moles of cyclohexene × molar mass of cyclohexene

Theoretical yield = 0.0444 moles of cyclohexene × 82.143 g/mol

Theoretical yield = 3.65 g of cyclohexene

Answer:

2.75M

Explanation:

Density = mass/volume

Density of glycerol (C3H8O3) at 15°C is given as 1.2656 g/mL.

Volume of glycerol at this same temperature before dissolving in water = 50mL

Hence, using Density = mass/volume

1.2656 = mass/50

mass = 1.2656g/mL × 50mL

mass = 63.28g

Molarity of solution = number of moles (n) ÷ volume (V)

Volume of glycerol dissolved in water = 250mL = 0.250L

number of moles = mass/molar mass

Molar mass of C3H8O3 = 12(3) + 1(8) + 16(3)

= 36 + 8 + 48

= 44 + 48

= 92g/mol

n = 63.28g ÷ 92g/mol

n = 0.688mol

* Molarity = n/V

Molarity = 0.688/0.250

Molarity = 2.75M

Answer:

Water H2O + SULPHATE OXIDE

Answer:

5.38 L

Option D.

Explanation:

2 NaOH(s) + 2 Al(s) + 6 H₂O(l)   →  2 NaAl(OH)₄(s)  + 3 H₂(g)

We convert mass of Al to moles:

4.32 g . 1 mol /26.98g = 0.160 moles

As NaOH is in excess, aluminum is the limiting reactant.

We see stoichiometry, were ratio is 2:3.

2 moles of Al can produce 3 moles of hydrogen

Our 0.160 moles may  produce (0.160 . 3)/2 = 0.240 moles of H₂.

We know that 1 mol of any gas at STP conditions is contained in 22.4L

So let's make the conversion factor:

0.240 mol . 22.4L / 1mol = 5.38 L

Answer:

10.5 × 10^5 M

Explanation:

E°cell = E°cathode - E°anode

E°cell = 0.85 - (-0.74) = 1.59 V

From Nernst's equation;

Ecell = E°cell - 0.0592/n log Q

1.499 = 1.59 - 0.0592/6 log [Cr^3+]/6.35x10^-4

1.499 - 1.59 = - 0.0592/6 log [Cr^3+]/6.35x10^-4

-0.091 = -0.00987 log [Cr^3+]/6.35x10^-4

-0.091/ -0.00987 = log [Cr^3+]/6.35x10^-4

9.22 = log [Cr^3+]/6.35x10^-4

Antilog (9.22) = [Cr^3+]/6.35x10^-4

1.66 × 10^9 = [Cr^3+]/6.35x10^-4

[Cr^3+] = 1.66 × 10^9 × 6.35x10^-4

[Cr^3+] = 10.5 × 10^5 M

Answer:

Protein biochemistry is the study of proteins. Protein biochemistry is a scientific field dedicated to the study of proteins, complex chains of amino acids which make up the building blocks of all living organisms.

Explanation:

I hope that helped

Copy and Pasted!

Answer:

Listen to what guy said on top.

Explanation:

polypeptide structures consisting of one or more long chains of amino acids residue.....

or my answer

Answer:

The material properties of nanostructures are different from the bulk due to the high surface area over volume ratio and possible appearance of quantum effects at the nanoscale. ... Yu; they found that the structural distortions on the quantum dots depend both on the kind of dopant and on the size of the dots.

Explanation:

hope it helps

Answer:

–0.09

Explanation:

From the question given above, the following data were obtained:

Measured value = 5.88 g

Actual value = 5.97 g

Error =?

The error in the student's measurement can be obtained as follow:

Error = Measured value – Actual value

Error = 5.88 – 5.97

Error = –0.09

Therefore, the error in the student's measurement is –0.09

Answer:

Pharmaceutical laboratory helps in devloping and conducting research, vaccines. Various kinds of drugs and chemical substances used and are produced at a Pharmaceutical laboratory.

The pharmaceutical laboratories performs with various hazardous substances that results in exposure to various chemicals, biological substances and radiation. To avoid any injury or infection labs need to maintain all safety measures.

Spillage and relaseing chemical substances can be lethal during transportaions by safety measures for heling in for manufacturing of such therapeutic agents spillage and avoid wastage.

Maintaining good safety standards in the pharmaceuticals laboratory will help promote the health of technicians and workers which in turn will increase productivity and attain positive outcomes.

Answer:

The halogen is Iodine.

Explanation:

Using the ideal gas equation, we find the number of moles of gas present, n.

PV = nRT where P = pressure of gas = 1.41 atm, V = volume of gas = 109 mL = 0.109 L, n = number of moles of gas, R = molar gas constant = 0.082 L-atm/mol-K and T = temperature of gas = 398 K

Since PV = nRT, making n subject of the formula, we have

n = PV/RT

substituting the values of the variables into the equation, we have

n = 1.41 atm × 0.109 L/(0.082 L-atm/mol-K × 398 K)

n = 0.15369 atm-L/32.636 L-atm/mol

n = 0.0047 mol

Since n = m/M where m = mass of gas = 1.19 g and M = relative molecular mass of gas

So, M = m/n

M = 1.19 g/0.0047 mol

M = 252.7 g

Since halogens are diatomic the relative atomic mass is M/2 = 252.7g/2 = 126.34 g

From tables, the only halogen with this atomic mass is Iodine.

So, the halogen is Iodine.

Answer:

a. minus 10

Explanation:

An element in group 13 = Boron ,valence electrons = 3 , therefore, valence electrons in group 13 = group no. -10

An element in group 18 = Neon, valence electrons = 8 , therefore, valence electrons in group 18 = group no. - 10

For groups 13 through 18, the number of valence electrons in an atom is equal to the group number minus 10. Therefore, option (A) is correct.

Valence electrons in an atom can be described as the electrons occupying the outer most electron shell of an atom while the electrons in the inner shell are core electrons. Lewis structures can be helpful to calculate the number of valence electrons.

Valence electrons can be filled in several electron shells as they are caused interaction between atoms and responsible for the formation of chemical bonds. Only valence electrons can contribute to the formation of a chemical bond and decide the reactivity of the element.

The general electronic configuration of group 13 is ns²np¹ has three valence electrons. It can be determined as group number - 10 = 13 - 10 = 3.

The general electronic configuration of group 18 is ns²np⁶ has eight valence electrons. It can be determined as group number - 10 = 18 - 10 = 8.

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Answer:

only one substrate could be converted to product by the enzyme

Explanation:

If an enzyme obeys the lock and key model, it then follows that the design of the enzyme is unique to a particular substrate.

Just as only the correct key can effectively fit into a lock, only the appropriate substrate whose design matches that of the enzyme can fit into the enzyme.

Owing to the lock and key model of enzyme activity, only one enzyme could interact with a substrate to yield particular product.

Answer:

zero

Explanation:

I I think one should be so accurate with measurements and experiments

Answer:

As either mass increases, the gravitational force between them

increases.

Explanation:

According to Newton's law of universal gravitation;

F α m1m2/r^2

That is, the force between two masses in a gravitational field is directly proportional to the product of the two masses and inversely proportional to their distance apart.

Hence, as either of the masses increase, the force of gravitation between the two masses increases. Hence the answer.

Answer:

KBr dissolved in water.

Explanation:

A substance conducts electricity as a result of the presence of mobile ions in the substance.

An ionic substance such as KBr when dissolved in water releases free ions which become charge carriers in solution hence the solution conducts electricity. Solid ionic substances such as solid KBr and solid baking soda do not conduct electricity because the ions are strongly bound to each other in the crystal lattice.

Molecular substances such as sugar and alcohol do not conduct electricity even in solution.

Answer:

acetaldehyde

When acetaldehyde is heated with Fehling's solution, a red precipitate is formed.

Explanation:

Answer:

True

Explanation:

The word Organic refers to the methods used to cultivate and process farm agricultural products. Organic foods are edible and nutritious substances consumed (both plants and animals) that are free from the use of synthetics and chemicals. In plants, the include the use of organic manure that serves as fertilizers and carrying out the weeding process by hand weeding. In animals, diseases can be prevented by maintaining a clean house or rotational grazing.

The benefit of organic foods are to produce food substances with no chemical substances.

Answer:

Percentage of carbon:

[tex] { \tt{ = \frac{24}{30} \times 100\%}} \\ = 80\%[/tex]

Percentage of hydrogen:

[tex]{ \tt{ = \frac{6}{30} \times 100\%} } \\ = 20\%[/tex]

Answer:

Higher than the actual value

Explanation:

Titration is a volumetric process in which a known volume of solution is dispensed from a burette to react with a known volume of solution in a conical flask.

When acid-base titration is carried out in such a way that the base is in the burette and the acid is in the conical flask and drops of the base adhere to the inner walls of the flask, but do not actually mix with the solution, the calculated acid concentration would be higher than the actual value.

This is because;

From CA= CBVBnA/VAnB

When VB(volume of base) that reacted is lower than the actual volume recorded, then the calculated volume of CA(concentration of acid) is much higher than the actual value since drops of the base adhere to the inner walls of the flask.

Answer:

118.06 mL

Explanation:

The neutralization reaction between HBr (acid) and Ba(OH)₂ (base) is the following:

2HBr + Ba(OH)₂ → BaBr₂ + 2H₂O

According to the equation, 2 moles of HBr react with 1 mol Ba(OH)₂. Thus, at the equivalence point the moles of acid and base react completely:

2 moles HBr = 1 mol Ba(OH)₂

We can replace the moles by the product of the molar concentration (M) and volume (V):

2 x (M HBr) x (V HBr) = M Ba(OH)₂ x V Ba(OH)₂

Now, we introduce the data in the equation to calculate the volume in mL of Ba(OH)₂:

V Ba(OH)₂ = (2 x (M HBr) x (V HBr))/M Ba(OH)₂

                 = (2 x 0.311 M x 57.7 mL)/(0.304 M)

                 = 118.06 mL

Therefore, 118 mL of Ba(OH)₂ are needed.

Answer:

Copper iodide. I think

Answer:

hope it helps

Answer:

That is, the atom is a solid and indivisible mass. However, the fenomenom by which an iron atom emits particles when it is struck by light (known as the photoelectric effect) can not be explaind by this indivisible atom model.

Answer:

Explanation:

First we convert the given masses into moles, using the compounds' respective molar mass:

Then we multiply each amount by Avogadro's number, to calculate the number of molecules:

Answer:

See explanation

Explanation:

First we divide the percentage by mass of each element by it's relative atomic mass then we divide the quotients obtained by the lowest ratio obtained in the first step.

C- 76.57/12, H= 6.43/1, O = 17.00/16

C- 6.38/1.06, H= 6.43/1.06, O= 1.06/1.06

C- 6, H- 6, O- 1

Empirical formula: C6H6O

[(12 ×6) + (6 × 1) + (16 × 1)]n=94.11

[72 + 6 +16]n = 94.11

n = 94.11/94

n= 1

Molecular formula = C6H6O

2)

C- 53.30/12, H- 11.19/1, O- 35.51/16

C- 4.44/2.22, H- 11.19/2.22, O- 2.22/2.22

C- 2, H- 5, O- 1

Empirical formula: C2H5O

[(2×12) + (5× 1) + (1×16)]n = 90.12

[24 + 5 + 16] n = 90.12

n= 90.12/45

n= 2

Molecular formula = C4H10O2

Answer:

-270.76°C

Explanation:

Given that metal Thallium becomes superconducting below the temperature of 2.39 kelvin i.e. this temperature is critical temperature for Thallium and below critical temperature a metal offers no resistance to the flow of electric current. Also the metal below its critical temperature expels the magnetic field in such a way that they do not penetrate the metal and pass through its surface only.

We have the relation between kelvin scale and degree Celsius scale of temperature measurement as:

[tex]C = K - 273.15[/tex]

[tex]C=2.39-273.15\\ C=-270.76^{o}C[/tex]

Answer:

2.33 mol C

Explanation:

Step 1: Write the balanced generic chemical equation

3 A ⟶ C + 4 D

Step 2: Establish the appropriate molar ratio

According to the balanced equation, the molar ratio of A to C is 3:1.

Step 3: Calculate the number of moles of C produced from 7 moles of A

We will use the previously established molar ratio.

7 mol A × 1 mol C/3 mol A = 2.33 mol C

Answer:

a. Na+ is pH neutral

b. Ni2+ = weak acid

c. NH4+ = Weak acid

Explanation:

To know the nature of the cation we need to find the nature of its conjugate base.

If the conjugate base of the ion is a strong base, the ion is neutral.

If the conjugate base is a weak base, the ion is a weak acid:

a. Conjugate base Na+ = NaOH

Sodium hydroxide is a strong base:

Na+ is pH neutral

b. Conjugate base Ni²⁺: Ni(OH)2 is a weak base because is not completely soluble in water. That means:

Ni2+ = weak acid

c. Conjugate base NH4+: NH4OH. Weak base:

NH4+ = Weak acid

Answer:

O B. Alkaline earth metals

Explanation:

Noble gases → 8th column.

Alkali metal → first column.

Halogen → 7th

Answer:

B. Alkaline earth metals

Explanation:

Alkaline-earth metals: The alkaline-earth metals make up Group 2 of the periodic table, from beryllium (Be) through radium (Ra). Each of these elements has two electrons in its outermost energy level, which makes the alkaline earths reactive enough that they're rarely found alone in nature. But they're not as reactive as the alkali metals. Their chemical reactions typically occur more slowly and produce less heat compared to the alkali metals.