What is the pH of a 75.0 mL solution that is 0.045 M in weak base and 0.053 M in the conjugate weak acid

Answer:

visual ob

Explanation:

Answer:

all of the above

because these use all of your 5 senses

Answer:

3.63s take for the concentration of NO₂ to decrease from 0.62M to 0.28M

Explanation:

The general equation for a second-order reaction is:

1/[A] = kt + 1/[A]₀

Where [A] is actual concentration of the reactant (0.28M)

k is rate constant (0.54M⁻¹s⁻¹)

t is time the reaction takes (Our incognite)

And [A]₀ is initial concentration of reactant (0.62M)

Replacing:

1/0.28M = 0.54M⁻¹s⁻¹t + 1/0.62M

3.5714 = 0.54t + 1.6129

1.9585 = 0.54t

3.63s = t

Answer:

Substance D would be the correct answer.

Answer:

thoracic cavity

Explanation:

The ventral body cavity in human body is the front aspect of the human body. Ventral body cavity is combined with the combination of three components that include the thoracic cavity, the pelvic cavity and the abdominal cavity.

So, Thoracic cavity is the  components of the anterior cavity that refers to the the ventral internal organs above the diaphragm.

Hence, the correct answer is "thoracic cavity".

Answer:

H₂O is the excess reactant

Explanation:

A reactant is in excess when the other reactant is over and the first reactant is still present.

For the reaction:

Mg₂Si (s) 4H₂O (l) → 2Mg(OH)₂(aq) + SiH₄ (g)

We need to convert mass of each reactant to moles in order to find which reactant is in excess as follows:

Moles Mg₂Si -Molar mass: 76.7g/mol-:

50.0g * (1mol / 76.7g) = 0.652 moles of Mg₂Si

Moles H₂O - Molar mass: 18.02g/mol-:

50.0g * (1mol / 18.02g) = 2.78 moles of H₂O

For a complete reaction of 2.78 moles of H₂O are required:

2.78mol H₂O * (1mol Mg₂Si / 4mol H₂O) = 0.694 moles Mg₂Si

As there are just 0.652 moles, Mg₂Si is limiting reactant and

Answer:

D. H2SO4

Explanation:

The chemical  formula of a compound is an expression that stares out the elements (in form of symbols)present in a compound and the number of the atoms.

In the image;

There is one sulphur (S) atom, 4 oxygen(O) atoms and 2 hydrogen (H) atoms

The chemical formula is;

H2SO4.

The correct option is option D.

Answer:

Cr₂S₃

Explanation:

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

Mass of chromium (Cr) = 0.67 g

Mass of chromium sulfide = 1.2888 g

Empirical formula =?

Next, we shall determine the mass of sulphur (S) in the compound. This can be obtained as follow:

Mass of chromium (Cr) = 0.67 g

Mass of chromium sulfide = 1.2888 g

Mass of sulphur (S) =?

Mass of S = (Mass of chromium sulfide) – (Mass of Cr)

Mass of S = 1.2888 – 0.67

Mass of S = 0.6188 g

Finally, we shall determine the empirical formula of the compound. This can be obtained as follow:

Mass of Cr = 0.67 g

Mass of S = 0.6188 g

Divide by their molar mass

Cr = 0.67 / 52 = 0.013

S = 0.6188 / 32 = 0.019

Divide by the smallest

Cr = 0.013 / 0.013 = 1

S = 0.019 / 0.013 = 1.46

Multiply by 2 to express in whole number

Cr = 1 × 2 = 2

S = 1.46 × 2 = 3

Therefore, the empirical formula of the compound is Cr₂S₃

The empirical formula will be "[tex]Cr_2 S_3[/tex]".

Given:

Mass of Cr,

Mass of product,

Now,

→ [tex]Mass \ of \ Sulphur = Mass \ of \ product -Mass \ of \ Cr[/tex]

                                [tex]= 1.2888-0.67[/tex]

                                [tex]= 0.6188 \ g[/tex]

then,

→ [tex]Moles \ ratio \ of \ Cr:S = (\frac{0.67}{51.996} ): (\frac{0.61888}{32} )[/tex]

                                       [tex]= 0.0129: 0.0194[/tex]

                                       [tex]= 2:3[/tex]

Thus the above response is right.

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Answer: Photosynthesis

Explanation:

Answer:2

Explanationb

Answer:

d 1 1/2 oz.. of 80-proof liquor

1 1/2 oz. of 80-proof liquor is not equivalent to one drink. Hence, option D is correct.

Oz is an abbreviation for ounce. An ounce is equal to 1/16 pound (437 1/2 grains) and equal to 480 grains, or 1/12 pound.

1 1/2 oz. of 80-proof liquor is not equivalent to one drink.

Hence, option D is correct.

Learn more about oz here:

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#SPJ5

Answer:

dt = 4.32°C

Explanation:

Given the following data;

Mass = 16.33g

Quantity of heat, Q = 63.4J

Specific heat capacity = 0.899 J/g °C

To find the temperature change;

Heat capacity is given by the formula;

[tex] Q = mcdt[/tex]

Where;

Making dt the subject of formula;

[tex] dt = \frac {Q}{mc} [/tex]

Substituting into the equation, we have;

[tex] dt = \frac {63.4}{16.33*0.899} [/tex]

[tex] dt = \frac {63.4}{14.6807} [/tex]

dt = 4.32°C

Therefore, the change in temperature for this aluminum is equal to 4.32°C.

Answer:

B.) A Liquid turns into Gas.

Answer:

The type of plate boundary between the South American Plate and the African Plate is a divergent one.

The two plates move apart from each other.

Explanation:

The boundary between the South American Plate and the African Plate is a divergent boundary. The plates moved, and between them, there is an oceanic basin. The plates move on top of the mantle, and magma goes up the divergent areas creating new surfaces when it solidifies. The new surface is called a ridge.

Answer:

K

Explanation:

Ionization energy refers to the energy required to remove an electron from an atom. It usually increases across the period due to the increase in the size of the nuclear charge and decreases down the group due to increase in the number of shells.

If we look at the element, K, it has only one electron in its outermost shell. This implies that after this one electron is removed, the second ionization energy involves the removal of an electron from a filled shell.

This usually requires a lot of energy. Hence, the element having the highest difference in energy between first and second ionization energy is K.  

Answer:

0.8878 mol KClO4

Explanation:

Molar mass of KClO4 = 39.0983 + 35.453 + ( 15.9994 x 4 ) = 39.0983 + 35.453 + 63.9976 = 138.5489g/mol

but,

number of moles = mass in grams / molar mass where mass in grams = 123g, molar mass = 138.5489g/mol

number of moles = 123g / 138.5489g/mol = 0.8878mol

Therefore the number of moles present in 123 g of [tex] KClO_4[/tex] is 0.888 moles.

Given,

The weight of the [tex] KClO_4[/tex] is 123. grams

molecular weight of [tex] KClO_4[/tex] is [tex]39+35.5+16\times4=138.5 g[/tex]

138.5 g of [tex]KclO_4[/tex] is equal to one mole

Gram molecular wt. of a substance is equal to one mole

No. of moles = [tex]\frac{Wt}{GMW} [/tex]

123 g of [tex]KClO_4[/tex] is equal to [tex]\frac{123}{138.5}=0.888 moles [/tex]

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Answer:

12.7 mol

Explanation:

A chemist measures the amount of fluorine gas produced during an experiment. He finds that 482. g of fluorine gas is produced. Calculate the number of moles of fluorine gas produced.

Step 1: Given data

Mass of fluorine (m): 482. g

Step 2: Determine the molar mass (M) of fluorine

Fluorine is a diatomic molecule of chemical formula F₂. Its molar mass is:

mF₂ = 2 × mF = 2 × 19.00 g/mol = 38.00 g/mol

Step 3: Determine the number of moles (n) corresponding to 482. g of fluorine

We will use the following expression,.

n = m/M

n = 482. g/(38.00 g/mol)

n = 12.7 mol

Answer:

Chemical because it alters the identity of the substance

Answer:

formula of starch is (C6H10O5)n, where n is the number of glucose molecules in the chain.

Explanation:

Answer:

3.02

Explanation:

Step 1: Given and required acid

pH of the solution: 4.34

pKa of lactic acid: 3.86

Step 2: Calculate the ratio of the lactate concentration to the lactic acid concentration in this solution

We have a buffer system formed by a weak acid (lactic acid) and its conjugate base (lactate ion). We can find the ratio of the lactate concentration to the lactic acid concentration in this solution using the Henderson-Hasselbach equation.

pH = pKa + log [lactate]/[lactic acid]

4.34 = 3.86 + log [lactate]/[lactic acid]

[lactate]/[lactic acid] = 3.02

Answer:

Because heat causes alcohol to volatilize, instead of burning it.

The combustion is not fulfilled since this is detached from the surface of the banknote that would be the necessary product to burn, in addition to considering that the necessary temperature is not reached

Explanation:

When water and alcohol are joined, they form a solution with high evaporation power, plus alcohol that has a higher degree of volatility than water, this is how these liquids are not retained on the surface of the banknote with heat and they are not it burns.

Answer:

A and 3

B and 2

C and 1

Explanation:

Ionic bonding is the transfer of electrons from a cation to an anion.

Covalent bonding is the sharing of electrons between nonmetal atoms.

Metallic bonding is the sea of electrons metal cations.

Hope this helped!

Answer:

an unbalanced force

Explanation:

I think this statement is True.

Answer:

Gravitational force of attraction G(f) = 2.44 x 10⁻⁷ (approx.)

Explanation:

Given:

Mass M1 = 26 kg

Mass M2 = 5.1 kg

Distance r = 0.19 m

Find:

Gravitational force of attraction G(f)

Computation:

Gravitational force of attraction G(f) = G(m1)(m2)/r²

Gravitational force of attraction G(f) = [6.67 x 10⁻¹¹](26)(5.1)/(0.19)²

Gravitational force of attraction G(f) = 8.84 x 10⁻⁹ / 0.0361

Gravitational force of attraction G(f) = 2.44 x 10⁻⁷ (approx.)

Answer:

[tex]m_{H_2O}=2.22gH_2O[/tex]

Explanation:

Hello!

In this case, since the combustion of butane is:

[tex]C_4H_{10}+\frac{13}{2} O_2\rightarrow 4CO_2+5H_2O[/tex]

As there is an excess of oxygen, we can compute the mass of water by simply using the molar masses of butane and water and the 1:5 mole ratio between them as shown below:

[tex]m_{H_2O}=1.43gC_4H_{10}*\frac{1molC_4H_{10}}{58.14gC_4H_{10}} *\frac{5molH_2O}{1molC_4H_{10}} *\frac{18.02gH_2O}{1molH_2O} \\\\m_{H_2O}=2.22gH_2O[/tex]

Best regards!

Answer:

The alkyl ether was yet to be totally dried off after the student recrystallize it .

The suggestion to the student is to redry the alkyl ether product and then reweigh

Explanation:

Based on the information the likely explanation for the problem that arise is that the alkyl ether was not totally dried after the student recrystallize the product which lead to the increase in mass from 270mg to 280mg gaining extra mass of 10mg (270mg -280mg).

Therefore what would be my suggestion to the student is that they should redry the alkyl ether product again and make sure that the water is totally dried off and then reweigh or weigh the product again for the second time .

Answer:

I think that it might be C. I'm not an expert so please don't blame me, I'm sorry if i'm wrong!

Explanation:

Answer:There are two types of atomic bonds - ionic bonds and covalent bonds. They differ in their structure and properties. Covalent bonds consist of pairs of electrons shared by two atoms, and bind the atoms in a fixed orientation. Relatively high energies are required to break them (50 - 200 kcal/mol). Whether two atoms can form a covalent bond depends upon their electronegativity i.e. the power of an atom in a molecule to attract electrons to itself. If two atoms differ considerably in their electronegativity - as sodium and chloride do - then one of the atoms will lose its electron to the other atom. This results in a positively charged ion (cation) and negatively charged ion (anion). The bond between these two ions is called an ionic bond.

Answer:

I think the answer is h

Explanation:

when you let the balloon go, all the air the is inside comes out causing it to move forard

Answer:

Not all conflicts are harmful to an organization

Explanation:

Not all conflicts in an organization are harmful to that organization.

Conflicts can be good for an organization. Even though conflicts may always seem difficult, they could bring about growth and changes which are good for all organizations.

Conflict may have positive or negative results when they occur. How these conflicts are approached is what determines the result.

Positive conflict can be constructive, it births new ideas, gives opportunities for creativity and skills expansion and can solve continuous problems.