really need help with this

Answer:

advantages:

. The error due to weighing the solute can be minimised by using concentrated stock solution that requires large quantities of solute. 2. We can prepare working standards of different concentrations by diluting the stock solution which is more efficient since consistency is maintained

3. Some of the concentrated solutions are more stable and are less likely to support microbial growth than working standards used in the experiments.

Answer:

Disinfecting (or boiling)

Explanation:

They'd want to disinfect everything so that it is germless. Boiling is a possible answer as well because you can boil certain things to rid them of germs.

Answer:

1.4 moles/ 2.0 L= 0.7 M

Explanation: Molarity= moles of solute/ Liters of solution

therefore just plug the numbers in and you'll find the molarity to equal. 0.7

Answer:

I won't say I'm confident with this because I'm not sure if the second one is even correct, but I hope I helped you and didn't make things worse lol.

No

B is your answer

If the ignition temperature of a fuel is lower than the room temperature, then it can catch fire very easily.

Therefore for an ideal fuel, the ignition temperature should be higher than the room temperature.

let's observe one by one

#1

If ignition temperature is below room temperature the fuel can catch fire at once.

#2

Ignition temperature above room temperature is applicable as the fuel won't catch fire easily

#3

It's boiling point of water not fuels

#4

Equal to room temperature is same as first one can cause damage

Answer:

The independent variable is the calculator

The dependent variable is the speed of solving the problem.

The constant variable is the same set of problems that were assigned to two groups of students.  

The dependent variable is the one that is being tested by experimentation. The dependent variable depends on the independent variable.  

The independent variable can b changed by the experimenter whereas the constant variable remains unchanged throughout the experiment.  

Answer:

Controlled Variable: The same math problems

Dependent Variable: The amount of time taken to answer

Independent Variable: One group using calculators and the other group not using calculators.

Explanation:

The dependent variable is the variable being tested and the independent variable is what is being changed. The controlled is what is staying the same.

Answer:

[tex]\huge\boxed{\sf v = 0.017 \ L}[/tex]

Explanation:

Given Data:

Mass = m = 0.08 g

Molar mass of C₂H₂F₄ = (12×2) + (1×2) + (19×4)

= 24 + 2 + 76 = 102 g/mol

Pressure = P = 1.14 atm

Temperature = T = 19.1 °C + 273 = 292.1 K

Gas Constant = R = 0.08206 L atm K⁻¹ mol⁻¹

Required:

Volume = v = ?

Formula:

Pv = nRT

Solution:

Firstly, finding moles (n)

[tex]\displaystyle n = \frac{mass}{molar \ mass} \\\\n = \frac{0.08 }{102} \\\\n =0.0008 \ mol[/tex]

Now, Finding volume (v)

Rearranging formula

[tex]\displaystyle v = \frac{nRT}{P} \\\\v = \frac{(0.0008)(0.08206)(292.1)}{1.14} \\\\v = \frac{0.019}{1.14} \\\\v = 0.017 \ L\\\\\rule[225]{225}{2}[/tex]

39 g H

2

O

 contains

1.3

×

10

24

molecules H

2

O

.

Explanation:

One mole of water has a molar mass of

18.015 g/mol

and

6.022

×

10

23

molecules H

2

O

. Therefore,

1 mol H

2

O

=

18.015 g H

2

O

=

6.022

×

10

23

molecules H

2

1O

Multiply the given mass of water times the conversion factors that cancel grams and moles of water, leaving molecules of water, as demonstrated below.

39

g H

2

O

×

1

mol H

2

O

18.015

g H

2

O

×

6.022

×

10

23

molecules H

2

O

1

mol H

2

O

=

1.3

×

10

24

molecules H

2

O

39 g H

2

O

 contains

1.3

×

10

24

molecules H

2

O

.

Explanation:

One mole of water has a molar mass of

18.015 g/mol

and

6.022

×

10

23

molecules H

2

O

. Therefore,

1 mol H

2

O

=

18.015 g H

2

O

=

6.022

×

10

23

molecules H

2

1O

Multiply the given mass of water times the conversion factors that cancel grams and moles of water, leaving molecules of water, as demonstrated below.

39

g H

2

O

×

1

mol H

2

O

18.015

g H

2

O

×

6.022

×

10

23

molecules H

2

O

1

mol H

2

O

=

1.3

×

10

24

molecules H

2

O

39 g H

2

O

 contains

1.3

×

10

24

molecules H

2

O

.

Explanation:

One mole of water has a molar mass of

18.015 g/mol

and

6.022

×

10

23

molecules H

2

O

. Therefore,

1 mol H

2

O

=

18.015 g H

2

O

=

6.022

×

10

23

molecules H

2

1O

Multiply the given mass of water times the conversion factors that cancel grams and moles of water, leaving molecules of water, as demonstrated below.

39

g H

2

O

×

1

mol H

2

O

18.015

g H

2

O

×

6.022

×

10

23

molecules H

2

O

1

mol H

2

O

=

1.3

×

10

24

molecules H

2

O

Methane in fuel cells are not burned and therefore, help to reduce pollutants commonly associated with fossil fuel combustion.

Fossils fuels are fuels wgich are produced from fossils which have decomposed under intense heat and pressure over a long period of time.

Fossils fuels include:

Fossils fuels combustion release pollutants into the atmosphere and have greatly contributed to global warming.

Since methane in fuel cells are not burned, it will help to reduce pollutants commonly associated with fossil fuel combustion.

Learn more about fossil fuels at: https://brainly.com/question/79954

Answer:

Morphine contains total 40 atom(s); 19 Hydrogen atom(s), 17 Carbon atom(s), 1 Nitrogen atom(s) and 3 Oxygen atom(s).

Explanation:

It gets basic

ie ph>7 for basic solutions

Answer:

[tex]\huge\boxed{\sf n = 7.36 \ mol}[/tex]

Explanation:

Given Data:

Volume = v = 42.19 L

Pressure = P = 428.792 kPa = 4.23 atm

Temperature = 27.871 °C + 273 = 300.871 K

R = the gas constant = 0.08206 L atm K⁻¹mol⁻¹

Required:

No. of moles = n = ?

Formula:

nRT = Pv

Solution:

Rearranging formula

[tex]\displaystyle n = \frac{Pv}{RT} \\\\n = \frac{(4.23)(42.19)}{(0.08206)(300.871)} \\\\n = \frac{181.467}{24.69} \\\\n = 7.36 \ mol\\\\\rule[225]{225}{2}[/tex]

Based on the data given, the energy required to remove an electron from a hydrogen atom in the n = 11 state is -0.112 eV

Ionization energy is the energy requiredto remove an electron from a neutral atom or a cation in its gaseous state.

To calculate the energy required to remove the electron from a hydrogen atom in the n = 11 state, the formula below is used:

where

[tex]E_0 \: is \: ground \: state \: energy \: of \: hydrogen \: atom \: = -13.6 eV \\ [/tex]

substituting the values:

[tex]E_n = \frac{ - 13.6 × 1^{2}}{11^{2}} \: = - 0.112 \: eV[/tex]

Therefore, the energy required to remove an electron from a hydrogen atom in the n = 11 state is -0.112 eV

Learn more about ionization energy at: https://brainly.com/question/1445179

Answer:

option C is the correct answer

Explanation:

it belongs to alkanes series

for alkane series the formula is

C n H 2n+2

so the formula of b utane is

C 4 H 10

The correct answer is option C.C4H10

These isomers occur because they can branch off at the carbon chain. For example, butane has two isomers, C4H10. One of them has a "linear" carbon atom and the other has a branched chain.

Butane is a 4-carbon alkane, so its molecular formula is C4H10. There are two isomers. n-Butane and isobutane. Here, n-butane is a linear compound with four carbon atoms connected by a single covalent bond.

\Compounds with the same molecular formula but different arrangements of carbon atoms in the straight or branched chain are called chain isomers. n-Butane and isobutane are chain isomers because they have different carbon atom arrangements

Learn more about  isomerism here: https://brainly.com/question/18474884

#SPJ2.

Explanation:

Big C carbon surrounded by He helium

Answer:

determiner is a word that introduces a noun or provides information about the quantity of a noun.

Explanation:

The metal cans are recyclable. (determiner before the adjective describing a plural noun to specify which cans)

Metal cans are recyclable. (no determiner because it's optional for plural nouns and noun phrases)

Answer:

Because X-rays have wavelengths similar to the size of atoms

X rays are used to probe the crystal structure of a material because this have same wavelength as atoms of crystal have.

X rays are the type of electromagnetic radiations and it is produced when the fast moving electron collide with the target anode and sudden deceleration takes place.

X rays have the high energy so that it easily penetrate in any crystal molecule as they also have same wavelength as atoms of the crystals have.

Hence due to high energy and same wavelength was of atoms of crystal it is used to probe the crystal.

To know more about x rays, visit the below link:

https://brainly.com/question/11305216

#SPJ4

The plants which have a fibrous root system are

A fibrous root system is a root system which consists of large mass of roots of nearly equal size

Some few examples of plants with fibrous roots system are as follows:

In conclusion; the plants which have a fibrous root system are grasses and corns.

Learn more about fibrous root system:

https://brainly.com/question/1600214

Answer:

When Chinese researchers first edited the genes of a human embryo in a lab dish in 2015, it sparked global outcry and pleas from scientists not to make a baby using the technology, at least for the present.

When Chinese researchers first edited the genes of a human embryo in a lab dish in 2015, it sparked global outcry and pleas from scientists not to make a baby using the technology, at least for the present.It was the invention of a powerful gene-editing tool, CRISPR, which is cheap and easy to deploy, that made the birth of humans genetically modified in an in vitro fertilization (IVF) center a theoretical possibility

Explanation:

Now, it appears it may already be happening.

According to Chinese medical documents posted online this month (here and here), a team at the Southern University of Science and Technology, in Shenzhen, has been recruiting couples in an effort to create the first gene-edited babies. They planned to eliminate a gene called CCR5 in hopes of rendering the offspring resistant to HIV, smallpox, and cholera.

Answer:

joules per gram per degree (J/goC) or calories per gram per degree (cal/goC).

Explanation:

Answer:

Joules, Kelvin, or calories

Explanation:

The hydrogen ion concentration [H3O+] in an egg white containing 6.3 × 10-⁷M of [OH-] is 1.5 × 10-⁸M.

The hydrogen ion concentration of a solution can be calculated as follows:

pOH = - log [OH-]

pOH = - log [6.3 × 10-⁷M]

pOH = - [-6.2]

pOH = 6.2

Since pOH + pH = 14

pH = 14 - 6.2

pH = 7.8

pH = - log [H3O+]

7.8 = - log [H3O+]

[H3O+] = 10-⁷:⁸

[H3O+] = 1.5 × 10-⁸M

Therefore, the hydrogen ion concentration [H3O+] in an egg white containing 6.3 × 10-⁷M of [OH-] is 1.5 × 10-⁸M.

Learn more about hydrogen ion concentration at: https://brainly.com/question/15082545

Answer:  [tex]3.45*10^{-7}[/tex]

Explanation:

we can use the equation Ka * Kb = Kw

Kw is the equilibrium constant and always equals to [tex]1*10^{-14}[/tex]

we plug the given numbers into the equation, [tex]Ka * (2.9*10^{-8} )=(1*10^{-14} )[/tex]

now we just solve for Ka, [tex]Ka=\frac{1*10^{-14} }{2.9*10^{-8} }[/tex]

which gives us the value, [tex]Ka=3.45*10^{-7}[/tex]

hope this helped! ♡

The ka of the weak acid ha, whose conjugate base has kb 2. 9 × 10⁻⁸ is 3.45 × 10⁻⁷.

Ka value is the equilibrium constant found by the dissociation of acid.

By the equation

[tex]\rm ka \times kb = kw[/tex]

where kb = [tex]2.9 \times 10^-^8[/tex]

kw = [tex]1 \times 10^-^4[/tex]

Now, putting the values in the equation

[tex]1 \times 10^-^1^4 = ka \times 2.9 \times 10^-^8\\\\ka = \dfrac{1 \times 10^-^1^4}{2.9 \times 10^-^8} \\\\ka = 3.45 \times 10^-^7[/tex]

Thus, the ka of the weak acid ha, whose conjugate base has kb 2. 9 × 10⁻⁸ is 3.45 × 10⁻⁷.

Learn more about ka values

https://brainly.com/question/2796803

#SPJ4

Answer:

I have no clue this qestion is kinda stumping but it a really good question it got me thinking but i don't know if there is a right answer

Explanation:

I don't know

Answer:

the compound that has the smallest ions with the greatest charge

The compound that has the smallest ions with the greatest charge will have the strongest ionic bonds. Therefore, option C is correct.

Ionic compounds can be defined as solids formed by closely packed ions of opposite charge. An Ionic compound is commonly formed when metal combines with non-metal.

In ionic compounds, the ions are held together by ionic bonds. The ions are created by accepting or losing electrons in order to get their nearest noble gas configuration. In a reaction, the metals have a tendency to lose electrons to complete their octet while non-metals will gain electrons to fill their octet.

An ionic bond or electrovalent bond is a type of linkage generated from the electrostatic attraction between oppositely charged ions. Such a bond produces when the valence electrons of one atom are transferred permanently to another.

The more the charge on the ions and the smaller the ions stronger the ionic bond will be formed.

Learn more about ionic compounds, here:

brainly.com/question/17217225

#SPJ2

For a liter of a buffer that is 1. 5 m in acetic acid and 0. 70 m in sodium acetate, and with a  result in a buffer pH of 4.01, the moles of HCl required is mathematically given as x=0.313mol

Generally, the equation for the pH   is mathematically given as

pH=pKa+logsalt/acid

Generally, the equation for the Chemical Reaction   is mathematically given as

HCl+CH3CooNa---->NaCl+CH3OOH

Therefore

4.01=4.74+log\frac{0.8-x}{1.3+x}

-0.52=log\frac{0.8-x}{1.3+x}

x=0.313mol

In conclusion, The moles of HCl required is

x=0.313mol

Read more about Chemical Reaction

https://brainly.com/question/6876669

Buffer is a solution that prevents pH variation in a solution when base or acid is added. In a liter of buffer 0.313 mol of hydrochloric acid must be added.

pH is the potential of hydrogen and is given as,

[tex]\rm pH =\rm pKa + log \dfrac{salt}{acid}[/tex]

The chemical reaction is given as,

[tex]\rm HCl+CH_{3}COONa \rightarrow NaCl+CH_{3}OOH[/tex]

Given,

pH =4.01

pKa = 4.74

Concentration of salt = 0.8 - x

Concentration of acid = 1.3 + x

Substituting values in the pH formula:

[tex]\begin{aligned} 4.01 &= 4.74 + \rm log \dfrac{(0.8 - x)}{ (1.3 + x)}\\\\-0.52 &= \rm log \dfrac{(0.8 - x)}{ (1.3 + x)}\\\\&= 0.313 \;\rm mol\end{aligned}[/tex]

Therefore, 0.313 moles of HCl are needed.

Learn more about buffers here:

https://brainly.com/question/9875355

#SPJ4

Answer:

Ammonium carbonate is a neutral molecule. Charge on NH4 is +1 , so on (NH4)2 is +2 ( +1 * 2) ,lets take the charge on C to be x and O is -2 , so on O3 is -6 (3*-2). Therefore x= + 4. Hope it helps.

Explanation: