Which type of chemistry studies the chemical reactions that occur in the human body?
O biochemistry
O materials chemistry
O physical chemistry
O environmental chemistry

Answer:

C. 12 × 16

Explanation:

Let mH be the mass of atoms of hydrogen and mO be the mass of atoms of oxygen.  The atoms of oxygen have 16 times the mass of atoms of hydrogen. That is,

mO = 16 mH   [1]

Let mX be the mass of the atoms of X. Atoms of element X have 12 times the mass of atoms of oxygen. That is,

mX = 12 mO   [2]

If we substitute [1] in [2], we get

mX = 12 × 16 mH

If mH is 1, we get,

mX = 12 × 16 × 1

mX = 12 × 16

Answer:

Glass 1

Explanation:

Molarity is measured in moles of substance per liter.

For the sake of calculations, let's say that each glass contains 1 mole of juice and 1 liter after it is divided between the glasses. If you add an equal amount of water to glass 1 ( another liter), you now have:

Glass 1 = 1 mole / 2 liters = 0.5 M

Glass 1 = 1 mole/ 1 liter = 1 M

So glass 1 will have a lower molarity

Answer:

Explanation:

Answer:

Part A

Ag+ is the Lewis acid and NH3 is the Lewis base.

Part B

AlBr3 is the Lewis acid and NH3 is the Lewis base.

Part C

AlCl3 is the Lewis acid and Cl− is the Lewis base.

Explanation:

A Lewis acid is any specie that accepts a lone pair of electrons. Ag^+, AlBr3 and AlCl3 all accepted lone pairs of electrons according to the three chemical reaction equations shown. Hence, they are Lewis acids.

A Lewis base donates a lone pair of electrons. They include neutral molecules having lone pair of electrons such as NH3 or negative ions such as Cl- .

Answer: The value of [tex][H_{3}O^{+}][/tex] is 0.0012 M and [tex][OH^{-}][/tex] is [tex]1.02 \times 10^{-14}[/tex].

Explanation:

pH is the negative logarithm of concentration of hydrogen ion.

It is given that pH is 2.89. So, the value of concentration of hydrogen ions is calculated as follows.

[tex]pH = - log [H^{+}]\\2.89 = - log [H^{+}]\\conc. H^{+} = 0.0012 M[/tex]

The relation between pH and pOH value is as follows.

pH + pOH = 14

0.0012 + pOH = 14

pOH = 14 - 0.0012 = 13.99

Now, pOH is the negative logarithm of concentration of hydroxide ions.

Hence, [tex][OH^{-}][/tex] is calculated as follows.

[tex]pOH = - log [OH^{-}]\\13.99 = - log [OH^{-}]\\conc. OH^{-} = 1.02 \times 10^{-14} M[/tex]

Thus, we can conclude that the value of [tex][H_{3}O^{+}][/tex] is 0.0012 M and [tex][OH^{-}][/tex] is [tex]1.02 \times 10^{-14}[/tex].

Answer:

SO < CO2 < C3H8

Explanation:

Entropy refers to the degree of disorderliness of a system. The standard molar entropy of a substance refers to the entropy of 1 mole of the substance vunder standard conditions.

The molar entropy depends on the number of microstates in the system which in turn depends on the number of atoms in the molecule.

C3H8 has 11 atoms and hence the highest number of microstates followed by CO2 having three atoms and least of all SO having only two atoms.

Answer:

0.10 M Ca(CH3COO)2- Less soluble than in pure water.

0.10 M K2SO3- Less soluble than in pure water.

0.10 M NaNO3 - More soluble than in pure water.

0.10 M KCH3COO- Similar solubility as in pure water.

Explanation:

We have to cast our minds back to the idea of common ions effect. If any ion is already present in solution, the presence of that ion in solution prevents any solute containing a common ion with the solution from dissolving in that solution. In order words, the presence of a common ion makes a solute less soluble in a solvent than it is in pure water.

For instance, 0.10 M Ca(CH3COO)2 and K2SO3 both contain Ca^2+ and SO3^2- ions respectively which are also contained in the solute calcium sulfite.

The presence of these common ions in solution makes calcium sulfite less soluble in these solutions than it is in pure water because the equilibrium position for the dissolution of the solute lies towards the left hand side.

However, calcium sulfite is more soluble in 0.10 M NaNO3 than in pure water due to displacement reaction between the ions in solution.

The solubility of calcium sulfite and 0.10 M KCH3COO in pure water is quite comparable.

Answer:

Số gam muối ăn cần là 76:42,7%=177,986 g

Explanation:

Answer:

a) will react with water: K

b) will react with steam or acid, but not water: Cr & Sn

d) will not react with water, steam, or acid: Cu

Explanation:

K reacts violently with water.

Cr will react with steam to form an oxide + H gas and will react with most acids

Sn will react with steam to form SnO₂ + H gas and, though it does not react as rapidly as other metals in acid, it dissolves easily in concentrated acids

Cu is an extremely nonreactive metal, which is what makes it so suitable for wiring

Answer: The molar concentration of acetic acid in the vinegar is 0.539 M.

Explanation:

The formula used is:

[tex]M_1V_1=M_2V_2[/tex]

where,

[tex]M_1[/tex] and [tex]V_1[/tex] are the concentration and volume of base.

[tex]M_2[/tex] and [tex]V_2[/tex] are the concentration and volume of an acid.

Given:

Molar concentration of NaOH = 0.1798 M

Volume of NaOH = 30.01 mL

Volume of acetic acid = 10.0 mL

Now putting all the given values in the above formula, we get:

[tex]M_1V_1=M_2V_2\\\\0.1798M\times 30.01mL=M_2\times 10.0mL\\\\M_2=0.539M[/tex]

Thu, the molar concentration of acetic acid in the vinegar is 0.539 M.

Answer: The standard way to report this result is [tex]32.9\pm 0.3 mL[/tex]

Explanation:

The standard method of representing a result is:

[tex]\text{Calculated value }\pm \text{ Standard deviation}[/tex]

The reporting of a result is done in correct significant figures.

We are given:

Calculated value = 32.9 mL

Standard deviation = 0.3 mL

Rule of significant figures applied when numbers are added or subtracted:

The number having less number of significant figures after the decimal point will determine the number of significant figures in the final answer.

Number of significant figures after the decimal point = 1

Hence, the standard way to report this result is [tex]32.9\pm 0.3 mL[/tex]

Answer:

Hi so your answer is that to helping fix the climate change you have to : speak up , power your home with renewable engery , reduce water waste , dont waste food , and finally invest energy .

Explanation:

Really hope i helped , have a nice day :)

Answer:

we can reduce air pollution,which is one of the main cause of climate change.Climate change is not a hoxe if it is not attending the upcoming generations will suffer greatly.

Answer:

ZnCl2=ionic

MgS=ionic

CH4=molecular

Explanation:

ZnCl₂=ionic, MgS=ionic and CH₄=molecular compounds.

Thus, Ions with opposing charges that are kept together by electrostatic forces make up ionic compounds. Typically, a metal and a nonmetal combine to make them.

Atoms share electrons through covalent bonds to form molecular compounds.

When atoms of various elements share electrons through covalent bonds, molecules are created, also known as covalent compounds. These compounds consist of molecules made up of joined atoms, and the shared electrons strengthen the bonds between the atoms.

Thus, ZnCl₂=ionic, MgS=ionic and CH₄=molecular compounds.

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Answer:

3.93g are recovered

Explanation:

Pb(NO3)2 reacts with KCl as follows:

Pb(NO3)2 + 2KCl → 2KNO3 + PbCl2

To solve this question we need to find the moles of each reactant in order to find the limiting reactant:

Moles Pb(NO3)2 -Molar mass: 331.2 g/mol-

5.72g * (1mol/331.2g) = 0.01727 moles

Mole KCl -Molar mass: 74.5513g/mol-

5.85g * (1mol/74.5513g) = 0.07847 moles

For a complete reaction of 0.07847 moles of KCl are required:

0.07847 moles KCl * (1mol Pb(NO3)2 / 2mol KCl) = 0.03923 moles Pb(NO3)2

As there are just 0.01727 moles, Pb(NO3)2 is limiting reactant. Assuming 100% of yield:

Moles PbCl2 = Moles Pb(NO3)2

Mass PbCl2 -Molar mass: 278.1g/mol-

0.01727 moles * (278.1g / mol) = 4.80g

As percent yield is 81.9% = 0.819, the mass of PbCl2 recovered was:

4.80g * 0.819 = 3.93g are recovered

Answer:

Limiting reagent is the potassium carbonate.

Percent yield of calcium carbonate is: 39.3 %

Explanation:

The reaction is:

CaCl₂ + K₂CO₃ → CaCO₃ + 2KCl

Formula for percent yield is:

(Produced yield / Thoeretical yield) . 100

Firstly we determine the moles of each reactant, in order to say what is the limiting reagent: ratio is 1:1.

1 mol of chloride need 1 mol of carbonate.

14.570 g . 1 mol /110.98 g = 0.131 moles of CaCl₂

12.285 g . 1 mol / 138.2g = 0.0889 moles of carbonate.

Limiting reagent is carbonate. For 0.131 moles of CaCl₂ we need the same amount of carbonate and we have less moles.

Ratio is also 1:1, with calcium carbonate.

1 mol of potassium carbonate produces 1 mol of calcium carbonate

then, 0.0889 moles will produce the same amount of CaCO₃

We convert moles to mass: 0.0889 mol . 100.08g /mol = 8.89 g

That's the theoretical yield; to find the percent yield:

(3.494 g / 8.89g) . 100 = 39.3%

Answer:

còmo supòtànté insígídà pàtàtàk

Answer:

A physical change is a change in form.

A Chemical change is a change in materials.

Explanation:

Example of a physical change would be an ice cube meting.

Example of a chemical change would be mixing food coloring into a cup of water.

Explanation:

Efficiency = (output/input)×100%

70% = output/(800 W)

which means

output = 0.70×(800 W) = 560 W

Answer:

A form of energy that can be used by cells.

Explanation:

Answer:

Explanation:

Let us define oxidation and reduction.

Oxidation and reduction deal with the transferring of electrons between reactants. The reactant that loses electrons is oxidized, while the reactant that gains electrons is reduced.

In an oxidation-reduction reaction, the substance oxidized always loses electrons and the correct option is option D.

An oxidation-reduction (redox) reaction is a type of chemical reaction that involves the transfer of electrons between species. It consists of two half-reactions: an oxidation half-reaction, where a species loses electrons and increases its oxidation state, and a reduction half-reaction, where a species gains electrons and decreases its oxidation state.

In an oxidation half-reaction, the species that is oxidized is called the reducing agent or the electron donor, as it donates electrons. In a reduction half-reaction, the species that is reduced is called the oxidizing agent or the electron acceptor, as it accepts electrons.

Thus, the ideal selection is option D.

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Answer:

On heating, the van der Waals dispersion forces existing then will easily break as it has a low boiling point and sublimates into gas. On heating iodine in the test tube, iodine evolves as violet fuming gas.

Explanation:

Answer:

C) Polar

Explanation:

The correct answer is polar

The attraction of sodium and chloride ions by the water is mediated by the polar nature of water. Thus, option C is correct.

The polarity is given as the formation of the partial positive and negative charge over the species in the ionization process.

Water molecule is having one hydrogen bounded with 2 oxygen atoms, and oxygen being more electronegative develops a partial negative charge, while hydrogen develops a partial positive charge.

The positive charge hydrogen and the negative charge oxygen attracts the opposite charge sodium and chloride ions. Thus, the attraction is mediated due to the polar nature of water. Hence, option C is correct.

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Answer:

pH = 8.87

Explanation:

Hydroiodic acid, HI, is a strong acid that reacts with ammonia, NH3, to produce ammonium ion, NH⁴⁺. That means the moles of HI added = moles of NH3 consumed and moles of NH4⁺ produced.

Initial moles NH₄⁺:

0.225L * (0.298mol/L) = 0.06705 moles

Initial moles NH3:

0.225L * (0.478mol/L) = 0.10755 moles

After the reaction the moles are:

0.10755moles NH3 - 0.0560moles = 0.05155 moles NH3

0.06705moles NH4+ + 0.0560moles = 0.12305 moles NH4+

Using H-H equation for weak bases:

pOH = pKb + log ([NH4+] / [NH3])

pKb for ammonia is 4.75, [NH4+] could be the moles of NH4+ = 0.12305mol,

[NH3] = 0.05155moles

Replacing:

pOH = 4.75 + log (0.12305mol / 0.05155moles)

pOH = 5.13

pH = 14-pOH

Explanation:

the answer is in the image above

Answer:

Kc = 0.630

Explanation:

The equilibrium of the thiocyanate system occurs as follows:

FeSCN²⁺(aq) ⇄ Fe³⁺(aq) + SCN⁻(aq)

And equilibrium constant, kc, is:

Kc = [SCN⁻] [Fe³⁺] / [FeSCN²⁺]

Replacing with the gven concentrations:

Kc = 0.639M*0.494M / 0.501M

Answer:

D.) ±0.01 cm?​

Explanation:

Since 32.23 cm has two decimal places, the uncertainty is taken as one-half the last decimal pace.

The last decimal place is 0.03. Half of this is 0.03 cm/2 = 0.015 cm.

Since we cannot go below two decimal places, we ignore the 5 in 0.015 cm.

So, we have our uncertainty as 0.01 cm.

So, the best expression of the uncertainty in the measurement 32.23 cm is ± 0.01 cm.

So, the answer is D. which is ± 0.01 cm.

Answer:

Eu(ClO3)3

Explanation:

The chlorate ion is written as follows, ClO⁻ ₃. We can see from this that the ion is univalent.

From the formula, Eu203, it is easy to see that the europium ion is trivalent.

Hence, when a compound is formed between the europium ion and chlorate ion, the compound will be written as Eu(ClO3)3.

This is so because, when ionic compounds are formed, there is an exchange of valence between the ions in the compound. This gives the final formula of the ionic substance.

Answer:

a) [NOCl] = 0.968 M

[NO] = 0.032M

[Cl²] = 0.016M

b) [NOCl] = 1.992M

[NO] = 0.008 M

[Cl2]  = 1.004 M

Explanation:

Step 1: Data given

Temperature = 35°C = 308K

K = 1.6 × 10^-5

Step 2: The reaction

2 NOCl(g) ⇌ 2 NO(g) + Cl2(g)

For 2 moles NOCl we'll have 2 moles NO and 1 mol Cl2

Step 3

a. 2.0 mol pure NOCl in a 2.0 L flask

Concentration at the start:

Concentration = mol / volume

[NOCl] = mol / volume

[NOCl] = 2.0 / 2.0 L

[NOCl] = 1.0 M

[NO] = 0 M

[Cl] = 0M

Concentration at the equillibrium

[NOCl] = 1.0M - 2x

[NO] = 2x

[Cl2]= x

K = [Cl2][NO]² / [NOCl]² = 1.6*10^-5

1.6*10^-5 = ((2x)² * x) / (1.0-2x)²

x = 0.016

[NOCl] = 1.0 -  2*0.016 = 0.968 M

[NO] = 2*0.016 = 0.032M

[Cl²] = 0.016M

b. 2.0 mol NOCl and 1.0 mol Cl2 in a 1.0 L flask

Concentration at the equillibrium

[NOCl] = 2.0 mol / 1.0 L = 2.0 M

[NO] = 0 M

[Cl2]= 1.0 mol / 1.0 L = 1.0 M

Concentration at the equillibrium

[NOCl] = 2.0M - 2x

[NO] = 2x

[Cl2]= 1.0 + x

K = [Cl2][NO]² / [NOCl]² = 1.6*10^-5

1.6 *10^-5 = (2x)²*(1.0+x) / ((2.0-2x)²)

1.6 *10^-5= (2x)² * 1 )/2.0²

1.6 *10^-5= 4x² / 4 = x²

x = [tex]\sqrt{1.6 *10^-5}[/tex] = 4.0*10^-3

[NOCl] = 2.0 - 2*0.004 = 1.992M

[NO] = 2*0.004 = 0.008 M

[Cl2] = 1+ 0.004M = 1.004 M