What is the mass of NaCl required to make 140 grams of a 12% solution of NaCl in water?
12 grams
14 grams
17 grams
18 grams

Answer:

0.723 moles (5 s.f.)

Explanation:

Whenever there is a chemical equation, ensure that it is balanced. This is because a balanced chemical equation tells us the mole ratio (not the ratio of their masses), which means the relationship of the number of moles of reactants or products with one another.

The chemical equation given has already been balanced. Looking at the coefficients of HBr and Ba(OH)₂, the mole ratio of HBr to Ba(OH)₂ is 2: 1.

• 1 mole of Ba(OH)₂ is needed to react with 2 mole of HBr

Find the number of moles of HBr present:

Number of moles= mass ÷mr

Amount of HBr

= 117 ÷(1 +79.9)

= 1.4462 moles (5 s.f.)

Since the amount of Ba(OH)₂ required is half the amount of HBr present,

amount of Ba(OH)₂ required

= 1.4462 ÷2

= 0.723 moles (3 s.f.)

Notes:

• mr

= relative molecular mass

= sum of relative atomic masses (which can be found in the periodic table) in a molecule

Answer:

3.1 kg

Explanation:

Step 1: Write the balanced combustion equation

C₈H₁₈ + 12.5 O₂ ⇒ 8 CO₂ + 9 H₂O

Step 2: Calculate the moles corresponding to 1.0 kg of C₈H₁₈.

The molar mass of C₈H₁₈ is 114.23 g/mol.

1.0 × 10³ g × 1 mol/114.23 g = 8.8 mol

Step 3: Calculate the moles of CO₂ produced from 8.8 moles of C₈H₁₈

The molar ratio of C₈H₁₈ to CO₂ is 1:8. The moles of CO₂ produced are 8/1 × 8.8 mol = 70 mol.

Step 4: Calculate the mass corresponding to 70 moles of CO₂

The molar mass of CO₂ is 44.01 g/mol.

70 mol × 44.01 g/mol = 3.1 × 10³ g = 3.1 kg

Answer:

two valence electrons

Explanation:

Magnesium is alkaline earth metal and belongs to group IIA of the periodic table. It has two valence electrons which are present in 3s subshell.

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Answer:

Magnesium has two valence electrons.

Explanation:

Magnesium is element 12 and belongs to Group 2 of the Periodic Table. An element in Group 2 has two valence electrons.

Here is a video which discusses how to determine the electron configuration of magnesium.

https://youtu.be/AOxaVdA-Sv0

Answer:

0.512 M

Explanation:

We'll begin by calculating the number of mole in 12 g of C₂H₆O₄. This can be obtained as shown below:

Mass of C₂H₆O₄ = 12 g

Molar mass of C₂H₆O₄ = (2×12) + (6×1) + (4×16)

= 24 + 6 + 64

= 94 g/mol

Mole of C₂H₆O₄ =?

Mole = mass /molar mass

Mole of C₂H₆O₄ = 12 / 94

Mole of C₂H₆O₄ = 0.128 mole

Next, we shall convert 250 mL to L. This can be obtained as follow:

1000 mL = 1 L

Therefore,

250 mL = 250 mL × 1 L / 1000 mL

250 mL = 0.25 L

Thus, 250 mL is equivalent to 0.25 L.

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

Mole of C₂H₆O₄ = 0.128 mole

Volume = 0.25 L

Molarity =?

Molarity = mole /Volume

Molarity = 0.128 / 0.25

Molarity = 0.512 M

Thus, the molarity of the solution is 0.512 M

Answer:

heat energy to keep you warm and light energy to be able to read your book

Explanation:

Answer:

Glycerol;Pyruvate

Explanation:

Metabolism of triglycerides occur through a process known as lipolysis. During triglyceride metabolism, Glycerol is converted to pyruvate or glucose through glycolysis or gluconeogenesis respectively. Glycerol enters these pathways by being converted to glycerol-3-phosphate (reaction catalyzed by glycerol kinase) which can in turn be converted to dihydroxyacetone phosphate (reaction catalyzed by glycerol-3-phosphate dehydrogenase).

NOTE: Dihydroxyacetone phosphate is a compound/substrate found in both glycolysis and gluconeogenesis.

The end product of glycolysis is pyruvate; this pyruvate, under aerobic condition is converted to acetyl coA (reaction catalyzed by pyruvate dehydrogenase complex), an intermediary of the Tricarboxylic acid cycle.

Answer:

2.0 × 10² g

Explanation:

Step 1: Write the balanced equation

2 NO₂ + 0.5 O₂ ⇒ N₂O₅

Step 2: Calculate the theoretical yield, in moles, of N₂O₅

The molar ratio of NO₂ to N₂O₅ is 2:1.

6.0 mol NO₂ × 1 mol N₂O₅/2 mol NO₂ = 3.0 mol N₂O₅

Step 3: Calculate the theoretical yield, in grams, of N₂O₅

The molar mass of N₂O₅ is 108.01 g/mol.

3.0 mol × 108.01 g/mol = 3.2 × 10² g

Step 4: Calculate the real yield, in grams, of N₂O₅

real yield = theoretical yield × percent yield

real yield = 3.2 × 10² g × 61.1% = 2.0 × 10² g

Answer:

The height of a column of ethanol is 13.1m

Explanation:

we begin by converting the density to SI unit= 0.789g/cm3* 1kg * [tex]100^{3}[/tex]* [tex]cm^{3}[/tex]

                                                                               cm * 1000g * [tex]1^{3}m^{3}[/tex]

                                                            = 789kg/m3

converting pressure to SI unit= 1 atm =101325 Pa

hence P= hdg

g= 9.81 m/s2

making h the subject of the formula

h= P/dg

h= 101325Pa/ 789kg/m3 * 9.81 m/s2

h= 13.1m

Answer:

C. Chemical reactions may have deteriorated the rubber

Explanation:

A tire ages with time and most of the time this happens due to chemical reactions in the rubber parts. This could happen faster due to heat and sun.

As a tire is deteriorating or aging, a chemical change happens. What happens is that more chemical bonds are going to be produced with time between the molecules. We call this the process of oxidation. This actually bad for the tire, because the rubber would turn out to be stuffs d strong causing the tires thread to separate and also disintegration would occur.

Answer:

179.5 feet

Explanation:

54.718 m converted to 179.5 feet.

Answer:

4 Fe  +   3 O2    ⇒  2  Fe2O3

Explanation:

iron metal reacts with oxygen gas to produce solid iron (III) oxide.

Fe   +   O2  ⇒  Fe2O3

4 Fe  +   3 O2    ⇒  2  Fe2O3

The balanced chemical equation for the reaction is

4Fe(s) + 3O₂(g) → 2Fe₂O₃(s)

From the question,

We are to write a balanced chemical equation for the reaction of iron metal with oxygen gas to produce solid iron (III) oxide

Iron metal is represented as Fe(s)

Oxygen gas is represented as O₂(g)

and Solid iron (III) oxide is represented as Fe₂O₃(s)

Now, we will write the balanced chemical equation for the reaction

The balanced chemical equation for the reaction is

4Fe(s) + 3O₂(g) → 2Fe₂O₃(s)

This means 4 moles of the iron metal reacts with 3 moles of oxygen gas to produce 2 moles of solid iron (III) oxide.

Hence, The balanced chemical equation for the reaction is

4Fe(s) + 3O₂(g) → 2Fe₂O₃(s)

Learn more here: https://brainly.com/question/23877810

Answer:

An example of a chemical property of iron would be that it is capable of combining with oxygen to form iron oxide, or rust.

Explanation:

You have no choice listed, so I provided an example.

Answer:

The answer would be [HCIO][OH-]

_________

[CIO-]

Explanation:

So, the answer would be (b).

Answer:

the last answer is right.

Answer:

See explanation

Explanation:

A system is said to have attained dynamic equilibrium when the rate of forward reaction and the rate of reverse reaction are equal.

Considering the system under consideration;

I2(s)⇄I2(g)

Heating the container converts solid iodine to purple coloured iodine vapour.

At equilibrium, there will be no net change in the amount of solid iodine and iodine vapour present in the system because the two processes (forward and reverse reactions) occur at the same rate at equilibrium.

Answer:

For the wavelenth of light spectrum, I believe the order would be red visible light, infrared, microwaves and radio waves.

Answer:

The combination of ions most likely to produce a precipitate is a group of answer choices:

lead nitrate soluble in water

Mg2+ and C2H3O2-.

Fe3+ and OH-.

Li+ and PO43-.

Pb2+ and NO3-.

NH4+ and SO42-.

Explanation:

Among the given options,

magnesium acetate, lithium phosphate, lead nitrate, ammonium sulfate are soluble in water.

The only one which is insoluble in water is [tex]Fe^3+[/tex] and [tex]OH^-[/tex] combination.

[tex]Fe(OH)_3[/tex] is insoluble in water. It forms a precipitate.

Answer:

This is because peroxy oxygen bonded to hydrogen can easily undergo nucleophilic protonation with the carbonyl carbon to form an alcohol

Explanation:

A ketone is a functional group that contains a carbonyl group (carbon-oxygen double bond ( R1R2-C=O).

The carbonyl carbon doubly bonded to the oxygen is electron deficient as a result of difference in electronegativity between carbon and oxygen, hence is susceptible to nucleophilic attacks

R1R2 - C = O

where R1 and R2 are organic substituents.

The peroxy oxygen that is bonded to hydrogen (H -O-O-R) is the electron-rich centre and easily attacks electron-deficient centres like the carbonyl carbon in ketones to form an alcohol.

The bond between the hydrogen attached to the peroxy oxygen is broken and the resultant hydrogen ion undergoes protonation with the oxygen of the carbonyl group to form an alcohol

R1R2 - C = O + H - O-O - R =>

R1R2- CH - OH + R - O-O-R1

Answer:

•cocoons are boiled in hot water for obtaining silk fibres from cocoons.

•camel wool considered a natural health product because it has excellent thermal proities

Answer:

hydronium and hydroxide ions are present both in pure water and in all aqueous solutions, and their concentrations are inversely proportional as determined by the ion product of water (Kw). The concentrations of these ions in a solution are often critical determinants of the solution’s properties and the chemical behaviors of its other solutes, and specific vocabulary has been developed to describe these concentrations in relative terms. A solution is neutral if it contains equal concentrations of hydronium and hydroxide ions; acidic if it contains a greater concentration of hydronium ions than hydroxide ions; and basic if it contains a lesser concentration of hydronium ions than hydroxide ions.

Answer:

hydronium and hydroxide ions are present both in pure water and in all aqueous solutions, and their concentrations are inversely proportional as determined by the ion product of water

Explanation:

Not my work! I hope this helps!  

Answer:

About 96 to 256 ATP molecules are produced.

Explanation:

About 96 to 256 ATP molecules may be synthesized in the full metabolism in oligosaccharide because one oligosaccharide molecule has 3 to 8 glucose atoms. About 30 to 32 ATP are produced from one glucose molecule so from three glucose molecule, 96 ATP produced whereas 256 ATP molecules are produced from 8 glucose molecules so we can say that About 96 to 256 ATP molecules from one oligosaccharide.

Answer:

TRUE

Explanation: because it is positively charged and protons are positive ions

Answer:

Matter is made up of many elements

Answer:

matter is made of smallest tiniest invisible particles.

Answer:

2HCl → H2 + Cl2 = decomposition

NaF + KBr → NaBr + KF = double replacement

Mg + MnCl2 → Mn + MgCl2 = single replacement

2Na + 02 → Na2O2 = combination

Explanation:

A chemical reaction involves the conversion of one or more substances called REACTANTS into other substances called PRODUCTS. There are different types of reactions depending on how it occurs, they include:

- Combination or synthesis reaction is a type of reaction in which two or more elements combine to form a single product. Example is:

2Na + 02 → Na2O2

- Single replacement is a type of reaction where one element is replaced by another in a compound or molecule. Example below shows that Manganese (Mn) is replaced by magnesium (Mg):

Mg + MnCl2 → Mn + MgCl2

- Double replacement is a type of reaction where two elements are replaced by other elements at a time. Example is:

NaF + KBr → NaBr + KF

- Decomposition is a type of reaction in which one molecule or compound is broken down into two or more products. Example is:

2HCl → H2 + Cl2

Answer:

infrared light

Explanation:

Answer:

mg2+ because it is a very good idea

Answer:

agua

Explanation:

por que estamos en la planeta