A student observes a chemical
reaction where two liquids are mixed together. After the liquids are mixed the beaker feels cold to touch. This reactions is an
example of a
reaction.
Synthesis
Combustion
Exothermic
Endothermic

Answer:

b. glass and charcoal

Explanation:

Step 1: Given data

Step 2: Determine which material will float in molten lead

Density is an intrinsic property of matter. Less dense materials float in more dense materials. The materials whose density is lower than that of lead and will therefore float on it are glass and charcoal.

Answer: A molecule contains hydrogen bonding if it contains hydrogen covalently bonded to (fluorine, oxygen, or nitrogen)

Explanation:

A hydrogen bond is a strong dipole-dipole attraction which occurs between

--> the hydrogen atom attached to a strongly electronegative atom, and

--> another strongly electronegative atom with a lone pair of electrons.

When an electronegative atom such as fluorine, oxygen or Nitrogen is bonded to hydrogen, a dipole develops causing the hydrogen to be partially negative. The electrostatic attraction between the partially positive hydrogen atom in one molecule and the partially negative atom of the more electronegative element in another molecule gives rise to the strong dipole-dipole attraction called hydrogen bonding.

Hydrogen fluoride, water and ammonia contain the three most electronegative elements, fluorine, oxygen and nitrogen respectively, linked directly to hydrogen. In addition, lone pairs of electrons are present in the fluorine, oxygen and nitrogen atoms of the three hydrides, making hydrogen bonds to form easily between them. These compounds which exhibits hydrogen bonding always have higher melting and boiling points.

Answer:

This would make the reaction more energetically favourable

Explanation:

Fatty acid synthesis starts with the carboxylation of acetyl CoA to malonyl CoA. This irreversible reaction is the committed step in fatty acid synthesis. The synthesis of malonyl CoA is catalyzed by acetyl CoA carboxylase, which contains a biotin prosthetic group.

Answer:

2.9 × 10²⁴ atoms Cu; 3.3 × 10²¹ atoms C; 1.44 × 10²⁵ atoms Hg; 9.63 × 10²² atoms Na

Explanation:

To convert moles to atoms, we need a conversion factor: Avogadro's number. There are 6.02 × 10²³ atoms in 1 mole of atoms.

4.9 mol Cu × 6.02 × 10²³ atoms Cu/1 mol Cu = 2.9 × 10²⁴ atoms Cu

5.4 × 10⁻³ mol C × 6.02 × 10²³ atoms C/1 mol C = 3.3 × 10²¹ atoms C

24.0 mol Hg × 6.02 × 10²³ atoms Hg/1 mol Hg = 1.44 × 10²⁵ atoms Hg

0.160 mol Na × 6.02 × 10²³ atoms Na/1 mol Na = 9.63 × 10²² atoms Na

Answer:

The less electronegative atom

Explanation:

Water contains polar bonds. Water is made up of oxygen and hydrogen. Oxygen is more electronegative then hydrogen so it is partial negative (because electron spend more time around oxygen in the polar bond), whereas, hydrogen has a  partial positive charge as it is less electronegative (electrons spend less time around hydrogen in this polar bond).

The equation for the energy required to melt 2 kg of gold is 3440 kJ.

Energy is the ability to do work or cause change. It is an essential part of everyday life and is present in many forms, such as thermal energy, electrical energy, chemical energy, and mechanical energy. Energy can be converted from one form to another in order to do work.

The equation for calculating the energy required to melt a certain mass of material is Q = m x Lf, where Q is the energy required (in joules), m is the mass of the material (in kilograms), and Lf is the latent heat of fusion (in joules per kilogram).
Using the table below, we can see that the latent heat of fusion for gold is 1760 kJ/kg. Therefore, the equation for the energy required to melt 2 kg of gold is: Q = 2 kg x 1760 kJ/kg = 3440 kJ.

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Answer:

Explanation:

BrCl₃ is an interhalogen compound with a hybridization of sp³d. The approximate bond angles can be predicted from the structure (attached below). Although, the lewis structure might be predicted to be trigonal bipyramidal from the structure, it is however a T-shaped geometry because of it's two lone pairs.

Also, from the structure attached, it can be predicted that the approximate bond angles about the central atom is 120° (360 ÷ 3) since each of the three chlorine atoms is equally spaced about the central atom.

The Lewis structure for BrCl₃ is attached to the image below. The bond angles around the central atom, bromine (Br), are 90 degrees between the bromine and each chlorine atom. Therefore, option B is correct.

A Lewis structure, also known as an electron-dot structure or Lewis dot structure is a diagram that represents the valence electrons of an atom or molecule.

Bromine (Br) is in Group 7A and has 7 valence electrons, while each chlorine (Cl) atom in Group 7A also has 7 valence electrons.

Br: 1 atom × 7 valence electrons = 7 valence electrons

Cl: 3 atoms × 7 valence electrons = 21 valence electrons

Total valence electrons = 7 + 21 = 28

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Answer:

0.1775 M

Explanation:

The reaction that takes place is:

Where HA is the unknown weak acid.

At the equivalence point all HA moles are converted by NaOH. First we calculate how many NaOH moles reacted, using the given concentration and volume:

That means that in 4.00 mL of the weak acid solution, there were 0.71 weak acid mmoles. With that in mind we can now calculate the concentration:

Answer:

64 g

Explanation:

Step 1: Write the balanced equation

2 Na + Cl₂ ⇒ 2 NaCl

Step 2: Calculate the moles corresponding to 25 g of Na

The molar mass of Na is 22.98 g/mol.

25 g × 1 mol/22.98 g = 1.1 mol

Step 3: Calculate the moles of NaCl formed from 1.1 moles of Na

The molar ratio of Na to NaCl is 2:2. The moles of NaCl formed are 2/2 × 1.1 mol = 1.1 mol.

Step 4: Calculate the mass corresponding to 1.1 moles of NaCl

The molar mass of NaCl is 58.44 g/mol.

1.1 mol × 58.44 g/mol = 64 g

Answer:

because atoms is just a chemical ahahahah

Explanation:

hope it helps ☺️

Dalton's hypothesis of atomic theory was given by John Dalton. The atoms of one element are the same as another and are not part of Dalton. Thus, option E is correct.

Dalton gave the atomic theory where atoms are the fundamental unit of the element of the periodic table. More than one element and atoms combine to form molecules and compounds.

The property of the atoms to get rearranged is the basis of the chemical reaction that results in the formation of the new product. This resulted in the formulation of chemical combinations. The atoms of the given element are said to be the same like the potassium contains the same atom.

The atoms of one element cannot be the same as another atom, like the atom of sodium and chloride are not the same. They are different in physical and chemical properties.

These atoms follow the law of conservation of mass. The atoms are composed of sub-atomic particles that have been constituted of neutrons, electrons, and protons.

Therefore, in option E. the atoms of two elements can never be the same.

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The direction of heat flow is increased which means blocks temperature is higher and hotter than it was before

Answer:

The answer is "It takes 1,70 mol of ethanol".

Explanation:

To make acetic acid, we must first write the balanced reaction that occurs of ethanol with oxygen

The response is balanced:

[tex]CH_3CH_2OH+O_2\to CH_3COOH+H_2O[/tex]

1 mol of ethanol creates 1 mol of According the equilibrium Ethanol moles, therefore, required 1.70 mol of water = 1.70 mol

Answer:

the molar mass of the element

Answer:

it might reach to 4g per L

Answer:

This is an oxidation-reduction (redox) reaction:

2 Ni0 - 4 e- → 2 NiII

(oxidation)

2 O0 + 4 e- → 2 O-II

(reduction)

Ni is a reducing agent, O2 is an oxidizing agent.

Answer:

True I think

hope this helps

Answer:

true

Explanation:

because it reacts with the water molecules by giving a proton to them

Answer:

answer = 22.5m

Explanation:

using

[tex]s = \frac{ {v}^{2} - {4}^{2} }{2a} [/tex]

s= (0²-21²)/2(-9.8)

s= -441/19.6

s= 22.5m

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Answer:

Balance the following reactions and identify the species that have been oxidized and the species that have been reduced.

CL2 +I- -------------> I2 +CL-

WO2 + H2 ---------------> W + H2O

CA + H2O -----------------> H2 + CA(OH)2

AL+ O2 --------------------> AL2O3

Explanation:

Oxidation is the process where an atom loses electrons.

During oxidation, the oxidation number of the atom increases.

Reduction is the process where an atom gains electrons.

During reduction, the oxidation number of the atom decreases.

The balanced chemical equations for the given reactions are shown below:

[tex]Cl_2 +2I^- -> I_2 + 2Cl^-[/tex]

Iodine undergoes oxidation and chlorine undergoes reduction.

[tex]WO_2 +2 H_2 -> W+ 2 H_2O\\[/tex]

In this reaction, W (tungsten) undergoes reduction and hydrogen undergoes oxidation.

[tex]Ca+2 H_2O ->H_2+Ca(OH)_2\\[/tex]

Ca undergoes oxidation and hydrogen undergoes reduction.

[tex]4Al+3O_2->2Al_2O_3\\[/tex]

Al undergoes oxidation and oxygen undergoes reduction.

Answer:

zero

Explanation:

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

Answer:

The concentrations of hydronium and hydroxide ions in a solution with pH 2.6 are 2.51*10⁻³ and 3.98*10⁻¹² respectively.

Explanation:

pH is a measure of the acidity or alkalinity of an aqueous solution. The pH indicates the concentration of hydrogen ions present in certain solutions. Mathematically it is defined as the opposite of the base 10 logarithm or the negative logarithm of the activity of hydrogen ions, whose equation is

pH= -log [H⁺]

So, being pH= 2.6 and replacing in the definition of pH:

2.6= -log [H⁺]

[tex][H^{+} ]=10^{-2.6}[/tex]

[H⁺]=2.51*10⁻³

pOH is a measure of the concentration of hydroxide ions (OH⁻). The sum between the pOH and the pH results in 14:

pOH + pH= 14

So, being pH= 2.6:

pOH + 2.6= 14

pOH= 14 - 2.6

pOH= 11.4

The pOH is defined as the negative logarithm of the activity of the hydroxide ions. That is, the concentration of OH⁻ ions:

pOH= - log [OH⁻]

Being pOH= 11.4 and replacing

11.4= -log [OH⁻]

[tex][OH^{-} ]=10^{-11.4}[/tex]

[OH⁻]= 3.98*10⁻¹²

The concentrations of hydronium and hydroxide ions in a solution with pH 2.6 are 2.51*10⁻³ and 3.98*10⁻¹² respectively.

Answer:

See explanation

Explanation:

All molecules possess the London dispersion forces. However London dispersion forces is the only kind of intermolecular interaction that exists in nonpolar substances.

So, the only kind of intermolecular interaction that exists in dimethyl ether is London dispersion forces.

As for ethyl alcohol, the molecule is polar due to the presence of polar O-H bond. In addition to London dispersion forces, dipole-dipole interactions and specifically hydrogen bonding also occurs between the molecules.

Because ethyl alcohol is polar, it is more soluble in water than dimethyl ether.

Answer:

Explanation:

Sample Response: If global warming continues, corals will continue to expel the algae from their cells to avoid poisonous buildup. This will cause corals to die. Without corals, the algae are not protected and cannot perform photosynthesis. This will cause the algae to die as well.

Sodium metal reacts rapidly with water to form a solution of sodium hydroxide (NaOH) and hydrogen gas (H2). This reaction is exothermic.

Equation:

2Na + 2H²0 --------}- 2NaOH + H²

Answer:

The correct answer is Option c (0.163 g).

Explanation:

Given:

Heat energy,

Q = 0.21 J

Specific heat,

c = 4.184 J/g°c

Change in temperature,

ΔT = 0.308°C

As we know,

⇒ [tex]Q=mc \Delta T[/tex]

By substituting the values, we get

 [tex]0.21=m\times 4.184\times 0.308[/tex]

     [tex]m=\frac{0.21}{0.308\times 4.184}[/tex]

         [tex]=\frac{0.21}{1.28867}[/tex]

         [tex]=0.163 \ g[/tex]

Answer: At equilibrium, the partial pressure of [tex]PCl_{3}[/tex] is 0.0330 atm.

Explanation:

The partial pressure of [tex]PCl_{3}[/tex] is equal to the partial pressure of [tex]Cl_{2}[/tex]. Hence, let us assume that x quantity of [tex]PCl_{5}[/tex] is decomposed and gives x quantity of [tex]PCl_{3}[/tex] and x quantity of [tex]Cl_{2}[/tex].

Therefore, at equilibrium the species along with their partial pressures are as follows.

                         [tex]PCl_{5}(g) \rightarrow PCl_{3}(g) + Cl_{2}(g)\\[/tex]

At equilibrium:  0.123-x          x              x

Now, expression for [tex]K_{p}[/tex] of this reaction is as follows.

[tex]K_{p} = \frac{[PCl_{3}][Cl_{2}]}{[PCl_{5}]}\\0.0121 = \frac{x \times x}{(0.123 - x)}\\x = 0.0330[/tex]

Thus, we can conclude that at equilibrium, the partial pressure of [tex]PCl_{3}[/tex] is 0.0330 atm.

0.152 moles

The mass of the oxygen gas produced = 4.87 g

Also, The molar mass of oxygen gas,  =  = 32 g/mol

The formula for the calculation of moles is shown below:

moles = [tex]\frac{Mass-taken}{Molar-mass}[/tex] *

Thus,

moles = [tex]\frac{4.87g}{32g/mol }[/tex]

Both given values and the answer is in 3 significant digits.

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*i put a dash between mass and taken as formulas do no spaces

Answer:

For 1: The product is phosphoric acid and the solution is acidic in nature.

For 2: The product is sodium hydroxide and the solution is basic in nature.

For 3: The product is nitric acid and the solution is acidic in nature.

Explanation:

For the given options:

(1): When diphosphorus pentoxide reacts with water, it leads to the formation of phosphoric acid, which makes the solution acidic in nature.

The chemical equation for the reaction follows:

[tex]P_4O_{10}+6H_2O(l)\rightarrow 4H_3PO_4(aq)[/tex]

(2): When disodium oxide reacts with water, it leads to the formation of sodium hydroxide, which makes the solution basic in nature.

The chemical equation for the reaction follows:

[tex]Na_2O+H_2O(l)\rightarrow 2NaOH(aq)[/tex]

(3): When dinitrogen pentoxide reacts with water, it leads to the formation of nitric acid, which makes the solution acidic in nature.

The chemical equation for the reaction follows:

[tex]3N_2O_5+3H_2O(l)\rightarrow 6HNO_3(aq)[/tex]

Answer:

Melting-point apparatus

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]