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2 years ago

An atom has 18 protons and 8 valence electrons which statement would best identify this element

Chemistry

2 answers:

lorasvet [3.4K]2 years ago

7 0

Argon has 18 protons which identifies the element and is in group Noble Gases which has 8 valence electrons.

fgiga [73]2 years ago

3 0

It would argon because the atomic number is the same as the protons.

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A student places four identical cells into four different liquids. Over time which cell will look the smallest WXY or Z

marta [7]

Answer: W

Explanation:

The cell in liquid W will look the smallest out of the four because of Osmosis.

Osmosis is a process by which water molecules move from an area of relatively higher concentration of water to an area with a relatively lower concentration through a selectively permeable membrane(cell membrane).

With W being saltier than the cell, water molecules will move from the cell to liquid W to balance the concentrations inside and outside the cell which will lead to the cell in W being smaller.

3 0

2 years ago

This is the chemical formula for acetic acid (the chemical that gives the sharp taste to vinegar): An analytical chemist has det

murzikaleks [220]

Answer:

0.11 mol

Explanation:

This is the chemical formula for acetic acid (the chemical that gives the sharp taste to vinegar): CH₃CO₂H. An analytical chemist has determined by measurements that there are 0.054 moles of oxygen in a sample of acetic acid. How many moles of hydrogen are in the sample?

Step 1: Given data

Formula of acetic acid: CH₃CO₂H

Moles of oxygen in the sample of acetic acid: 0.054 moles

Step 2: Establish the appropriate molar ratio

According to the chemical formula of acetic acid, the molar ratio of H to O is 4:2.

Step 3: Calculate the moles of atoms of hydrogen

We will use the theoretical molar ratio for acetic acid.

0.054 mol O × (4 mol H/2 mol O) = 0.11 mol H

3 0

2 years ago

5. Rubbing alcohol is a commonly used disinfectant and has a cooling effect when applied to the skin. The active ingredient in r

WITCHER [35]

Answer:

Explanation:

70% (vol/vol) means

cotnaimns 70 %(vol/vol) 70 ml of isoprapnol is there in 100 ml of Rubbing sold alcohol.

if it is 200 ml then obvouly it has the 70*2 =140 ml of isoproanol required.

8 0

2 years ago

What does the number represent in the isotope platinum-194?

vazorg [7]

The number in isotope platinum-194 stands for the total amount of protons and neutrons. In other words, this is the mass. =)

4 0

2 years ago

one method for generating chlorine gas is by reacting potassium permanganate and hydrochloric acid. how many liters of Cl2 at 40

Ronch [10]

Answer: The volume of chlorine gas produced in the reaction is 2.06 L.

Explanation:

For potassium permanganate:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Given mass of potassium permanganate = 6.23 g

Molar mass of potassium permanganate = 158.034 g/mol

Putting values in above equation, we get:

$\text{Moles of potassium permanganate}=\frac{6.23g}{158.034g/mol}=0.039mol$

For hydrochloric acid:

To calculate the moles of hydrochloric acid, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Molarity of HCl = 6.00 M

Volume of HCl = 45.0 mL = 0.045 L (Conversion factor: 1 L = 1000 mL)

Putting values in above equation, we get:

$6.00mol/L=\frac{\text{Moles of HCl}}{0.045L}\\\\\text{Moles of HCl}=0.27mol$

For the reaction of potassium permanganate and hydrochloric acid, the equation follows:

$2KMnO_4+16HCl\rightarrow 2MnCl_2+5Cl_2+2KCl+8H_2O$

By Stoichiometry of the reaction:

16 moles of hydrochloric acid reacts with 2 moles of potassium permanganate.

So, 0.27 moles of hydrochloric acid will react with = $\frac{2}{16}\times 0.27=0.033moles$ of potassium permanganate.

As, given amount of potassium permanganate is more than the required amount. So, it is considered as an excess reagent.

Thus, hydrochloric acid is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

16 moles of hydrochloric acid reacts with 5 moles of chlorine gas.

So, 0.27 moles of hydrochloric acid will react with = $\frac{5}{16}\times 0.27=0.0843moles$ of chlorine gas.

To calculate the volume of gas, we use the equation given by ideal gas equation:

$PV=nRT$

where,

P = pressure of the gas = 1.05 atm

V = Volume of gas = ? L

n = Number of moles = 0.0843 mol

R = Gas constant = $0.0820\text{ L atm }mol^{-1}K^{-1}$

T = temperature of the gas = $40^oC=[40+273]K=313K$

Putting values in above equation, we get:

$1.05atm\times V=0.0843\times 0.0820\text{ L atm }mol^{-1}K^{-1}\times 313K\\\\V=2.06L$

Hence, the volume of chlorine gas produced in the reaction is 2.06 L.

3 0

2 years ago