Please i really need help it's due today

pH of buffer solution : 4.32

A buffer solution is a solution that can maintain a good pH value due to the addition of a little acid or a little base or dilution.

The buffer solution can be acidic or basic

Acid buffer solutions consist of weak acids(H₂CO₃) and their salts.(NaHCO₃)

mol H₂CO₃

[tex]\tt 0.032\times 0.25=0.008[/tex]

mol NaHCO₃

[tex]\tt 0.02\times 0.15=0.003[/tex]

[tex]\tt [H^+]=Ka\dfrac{mole~weak~acid}{mole~salt}\\\\(H^+]=1.8\times 10^{-5}\dfrac{0.008}{0.003}=4.8\times 10^{-5}\\\\pH=5-log~4.8=4.32[/tex]

The procedure that Dr. Simmons will not include as part of her scientific experiment is uncontrolled variables.

When a scientific investigation is carried out, experiments are used as a method of verifying results. Generally, when an experiment is carried out, you want to verify that given circumstances generate a specific result.

The experiments must be as controlled as possible so that they can be repeated and thus create reliable laws. Therefore, Dr. Simmons will not include uncontrolled variables in her experiment, because these variables can modify the result of an investigation in many ways and limit the production of new knowledge.

Uncontrolled variables are generally not included in scientific investigations because they cannot be modified and they influence various results that cannot be considered reliable knowledge.

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We are given:

P1 = 1 atm                 P2 = 3 atm

T1 = 300 K               T2 = 600 K

V1 = 6 L                    V2 = v L

Finding the final Volume:

From the ideal gas equation:

PV = nRT

since in the given scenario, the universal gas constant (R) and number of moles(n) are constant

So, for both the cases, the value of n*R will be a constant k

Hence, we can write that:

PV / T = k        [where k is a constant]

Since the constant 'k' is the same for both the cases, we can write that:

P1V1 / T1 = P2V2 / T2

replacing the variables

1 * 6 / 300 = 3 * v / 600

1/50 = v / 200

v = 200/50

v = 4 L

Therefore, the volume of the gas at 600K and 3 atm will have a volume of 4 L

Answer:

The leftover is 15 g of oxygen rather than liquid hexane as the fuel limits the reaction.

Explanation:

Hello!

In this case, since the described combustion reaction is:

[tex]C_6H_{14}(l)+\frac{19}{2} O_2(g)\rightarrow 6CO_2(g)+7H_2O(g)[/tex]

Thus, since 5.2 g of hexane (86.2 g/mol) is reacted with 33.0 g of oxygen (32.0 g/mol) we can compute the mass of hexane that was actually consumed via stoichiometry with oxygen (1:19/2 mole ratio):

[tex]m_{C_6H_{14}}^{consumed \ by\ O_2}=33.0gO_2*\frac{1molO_2}{32.0gO_2}*\frac{1molC_6H_{14}}{\frac{19}{2}gO_2 } *\frac{86.2gC_6H_{14}}{1molC_6H_{14}} \\\\m_{C_6H_{14}}^{consumed \ by\ O_2}=9.36gC_6H_{14}[/tex]

It is proved then than the hexane won't have any leftover but oxygen does, as shown below:

[tex]m_{O_2}^{consumed \ by\ C_6H_{14}}=5.2gC_6H_{14}*\frac{1molC_6H_{14}}{86.2gC_6H_{14}} *\frac{\frac{19}{2}molO_2 }{1molC_6H_{14}} *\frac{32.0gO_2}{1molO_2} \\\\m_{O_2}^{consumed \ by\ C_6H_{14}}=18g[/tex]

It means the leftover of oxygen is:

[tex]m_{O_2}^{leftover}=33g-18g\\\\m_{O_2}^{leftover}=15g[/tex]

Regards!

Answer:

It emits 1.64 x 10⁻¹⁸J of energy

Explanation:

The n = 1 is a lower quantum level compared to n = 2.

When a hydrogen atom moves from a higher level to a lower one, it simply emits the energy difference between the two levels.

Answer:

A river and its tributaries make up a watershed (aka river system or drainage basin)

Pls mark me as brainliest

Answer:

river system

Explanation:

a river and all its tributaries make up a river system

Answer:

it is C

Explanation:

because Potassium iodide (KI) is an ionic compound which is made of the following ions: K+I−

Answer:

Carbohydrates

Explanation:

Answer:

ether group

Explanation: I looked it up

Answer: d

Explanation:

On edg

Answer:

A is probably ur answer

Explanation:

but if I'm wrong My bad and at least I tried

Electromagnetic energy

Explanation:

Growth is one of the characteristics of living things. It refers to the increase of an organism. A leaf is part of a plant, which is a photosynthetic organism i.e. an organism capable of producing its own food using energy from sunlight. Light energy is a part of the ELECTROMAGNETIC ENERGY.

This light energy is used to synthesize glucose (food) via photosynthesis. The glucose, which stores chemical energy in its bond is then broken down to yield ATP used for growth. Hence, the transformation of electromagnetic energy to light energy is how a leaf grow.

Answer:

An ionic bond forms when atoms transfer electrons.

Explanation:

Ionic bonds are formed when atoms transfer electrons. (In contrast, covalent bonds are formed when atoms share electrons.)

There's a distinction between the two: when two atoms react to form an ionic bond, one atom would completely lose one electron, while the other would completely gain that electron. The atom that loses the electron becomes a positively-charged ion called a cation, whereas the atom that gains the electron becomes a negatively-charged ion called an anion.

For example, consider the reaction between a sodium [tex]\rm Na[/tex] atom and a chlorine [tex]\rm Cl[/tex] atom: [tex]\rm Na + Cl \to NaCl[/tex].

When the sodium atom and the chlorine atom encounter, the sodium atom would lose one electron to form a positively-charged sodium ion, [tex]\rm Na^{+}[/tex]. The chlorine atom would gain that electron to form a negatively-charged chlorine ion [tex]\rm Cl^{-}[/tex].

These two ions will readily attract each other because of the opposite electrostatic charges on them. This electrostatic attraction (between two ions of opposite charges) is an ionic bond.

Overall, it would appear as if the sodium [tex]\rm Na[/tex] atom transferred an electron to the chlorine [tex]\rm Cl[/tex] atom to form an ionic bond.

In contrast, when two atoms react to form a covalent bond, they share electrons without giving any away completely. Therefore, it is possible to break certain covalent bonds apart (using a beam of laser, for example) and obtain neutral atoms.

On the other hand, when an ionic bond was broken, the result would be two charged ions- not necessarily two neutral atoms. The electron transfer could not be reversed by simply breaking the bond.

For example, when table salt [tex]\rm NaCl[/tex] is melted (at a very high temperature,) the ionic bond between the sodium ions and chloride ions would (mostly) be broken. However, doing so would only generate a mixture of [tex]\rm Na^{+}[/tex] and [tex]\rm Cl^{-}[/tex] ions- not sodium and chlorine atoms.

Answer:yea it’s transfer

Explanation:

Answer:

See explanation

Explanation:

The melting point range of a pure compound is about 1-2ºC of the expected melting point. An impure solid melts within a range   that is both larger than that of the pure substance  (>1ºC) and begin at a  lower temperature because impurities decrease the meting point. A melting range of 5º or more  indicates that a compound is impure.

Since the melting points of A and B are estimated  at 133 o C, the melting point range for each pure substance must be slightly different from each other. The melting point of the unknown is measured and its range is compared with the melting point ranges of pure A and B then decision can  now be made about the identity of the unknown solid.

Answer:

Changes in Properties Changes in properties result when new substances form. For instance, gas production, formation of a precipitate, and a color change are all possible evidence that a chemical reaction has taken place. ... Change in Color A color change can signal that a new substance has formed.

Explanation:

The chemical reaction indicate the formation of new substance by change in nature of original compound and shows chemical changes in the reaction.

Chemical reaction is defined as  process in which two or more molecules collide with the proper orientation and enough force to produce a new product.

It is also defined as a procedure in which one or more compounds, known as reactants, are changed into one or more distinct substances, known as products.

There are mainly seven types of reaction.

Thus, the chemical reaction indicate the formation of new substance by change in nature of original compound and shows chemical changes in the reaction.

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Answer:

1.089%

Explanation:

From;

ν =1/2πc(k/meff)^1/2

Where;

ν = wave number

meff = reduced mass or effective mass

k = force constant

c= speed of light

Let

ν =1/2πc (k/meff)^1/2  vibrational wave number for 23Na35 Cl

ν' =1/2πc(k'/m'eff)^1/2 vibrational wave number for 23Na37 Cl

The between the two is obtained from;

ν' - ν /ν  = (k'/m'eff)^1/2 - (k/meff)^1/2 / (k/meff)^1/2

Therefore;

ν' - ν /ν = [meff/m'eff]^1/2 - 1

Substituting values, we have;

ν' - ν /ν = [(22.9898 * 34.9688/22.9898 + 34.9688) * (22.9898 + 36.9651/22.9898 * 36.9651)]^1/2  -1

ν' - ν /ν = -0.01089

percentage difference in the fundamental vibrational wavenumbers of 23Na35Cl and 23Na37Cl;

ν' - ν /ν * 100

|(-0.01089)|  × 100 = 1.089%

Answer:

1.089%

Explanation:

From;

ν =1/2πc(k/meff)^1/2

Where;

ν = wave number

meff = reduced mass or effective mass

k = force constant

c= speed of light

Let

ν =1/2πc (k/meff)^1/2  vibrational wave number for 23Na35 Cl

ν' =1/2πc(k'/m'eff)^1/2 vibrational wave number for 23Na37 Cl

The between the two is obtained from;

ν' - ν /ν  = (k'/m'eff)^1/2 - (k/meff)^1/2 / (k/meff)^1/2

Therefore;

ν' - ν /ν = [meff/m'eff]^1/2 - 1

Substituting values, we have;

ν' - ν /ν = [(22.9898 * 34.9688/22.9898 + 34.9688) * (22.9898 + 36.9651/22.9898 * 36.9651)]^1/2  -1

ν' - ν /ν = -0.01089

percentage difference in the fundamental vibrational wavenumbers of 23Na35Cl and 23Na37Cl;

ν' - ν /ν * 100

|(-0.01089)|  × 100 = 1.089%

Answer:

2HBr + O2 = H20 +Br2

Explanation:

Answer:

4hbr(aq) + O2(g) = 2H2O + 2Br2

Explanation:

Answer:

4

Explanation:

[tex]\int\limits^a_b {x} \, dwetjernjtnx[/tex]

Answer:

32°c

Explanation:

Because in F it would be 0°f

Answer:

Check explanation section.

Explanation:

In order to be able to answer this question accurately,there is need to follow the formula below for the calculation;

Numbers of decades = total volume/ volume per decade. ----------------------(1).

So, we are given from the Question above that the volume of water in Lake Michigan = 13 billion gallons of water.

And if chicago uses 5 million gallons of water every decade.

Therefore, using the formula (1) above, we have;

Numbers of decades = 13 × 10^9/ 5 × 10^6 = 2.6 × 10^15 decades.

Answer:

vinegar and soap

Explanation:

Answer:

vinegar and soap

Explanation: just took the test

Answer:

c) H2O and HSO4-

Explanation:

The dehydration of 2-methylcyclohexanol occurs in the presence of H2SO4. Recall that acids are proton donors in solution; the equilibrium shown below is then set up,

H2SO4(aq)  +  H2O(l) ⇄H3O^+(aq) + HSO4^-(aq)

The species H2O and HSO4- are two proton acceptors in the system. According to the Brownstead- Lowry definition, a base is a proton acceptor in solution.

Hence H2O and HSO4- are bases present in the dehydration of 2-methylcyclohexanol.

Answer: The volume at an altitude of 20.0 km is 34.5289 L

Explanation:

Boyle's Law: This law states that pressure is inversely proportional to the volume of the gas at constant temperature and number of moles.

[tex]P\propto \frac{1}{V}[/tex]     (At constant temperature and number of moles)

[tex]P_1V_1=P_2V_2[/tex]

where,

[tex]P_1[/tex] = initial pressure of gas = 101.325 kPa ( at sea level)

[tex]P_2[/tex] = final pressure of gas = 10 kPa

[tex]V_1[/tex] = initial volume of gas = 3.40774 L

[tex]V_2[/tex] = final volume of gas = ?

Now put all the given values in the above equation, we get the final volume of gas.

[tex]101.325\times 3.40774=10\times V_2[/tex]

[tex]V_2=34.5289L[/tex]

Thus the volume at an altitude of 20.0 km is 34.5289 L

Therefore, the final pressure of the gas will be 3.75 atm

Answer:

747mL of the 0.157mL are needed

Explanation:

To find the grams of salt we need to convert these grams to moles using molar mass of magnesium nitrate (148.3g/mol). Then, with the molar concentration we can convert the moles to liters and, as last, to milliliters, as follows:

Moles Mg(NO₃)₂:

17.4g * (1mol / 148.3g) = 0.117 moles of magnesium nitrate

Volume:

0.117 moles * (1L / 0.157moles) = 0.747L

= 747mL of the 0.157mL are needed

In a 0.157M solution there are 0.157 moles per liter of solution

Answer:

it should be a base

Explanation:

this is because solutions such as bleach are usually slippery on the hands, and mostly bases are in cleaning solutions