As a 7 inch candle burns down, its height decreases 1/2 inch each hour. How many hours does it take for the candle to burn completely?

Answer:

[tex]8.42\ \text{mL}[/tex]

Explanation:

When the endpoint is reached the millimoles of sodium acetate and HCl will be equal.

[tex]\text{Volume of sodium acetate}=25\ \text{mL}[/tex]

[tex]\text{Molarity of sodium acetate}=0.033M[/tex]

[tex]\text{Molarity of HCl}=0.098M[/tex]

[tex]\text{Millimoles of sodium acetate}=25\times 0.033=0.825\ \text{mmol}[/tex]

Let [tex]V=\text{Volume of HCl}[/tex]

[tex]\text{Millimoles of HCl}=0.098V[/tex]

At end point the millimoles will be equal to that of sodium acetate

[tex]0.825=0.098V\\\Rightarrow V=\dfrac{0.825}{0.098}\\\Rightarrow V=8.42\ \text{mL}[/tex]

The volume of HCl required is [tex]8.42\ \text{mL}[/tex].

The volume of HCl required to required to reach endpoint is 8.42 mL

From the question,

We are to determine the volume of HCl required to reach endpoint

First, we will write a balanced chemical equation for the reaction.

The balanced chemical equation for the reaction is

CH₃COONa + HCl → CH₃COOH + NaCl

This means

1 mole of sodium acetate is required to completely neutralize 1 mole of HCl

Now, we will determine the number of moles of sodium acetate present

Using the formula

Number of moles = Concentration × Volume

Concentration of sodium acetate = 0.033 M

Volume of sodium acetate = 25.00 mL = 0.025 L

∴ Number of moles of sodium acetate present = 0.033 × 0.025

Number of moles of sodium acetate present = 0.000825 mole

Now,

Since, 1 mole of sodium acetate is required to completely neutralize 1 mole of HCl

Then,

0.000825 mole of sodium acetate would be required to completely neutralize 0.000825 mole of HCl

∴ The number of moles of HCl needed is 0.000825 mole

Now, for the volume of 0.098 M HCl required to reach endpoint

Using the formula

[tex]Volume = \frac{Number\ of\ moles}{Concentration}[/tex]

∴ Volume of HCl required to required to reach endpoint = [tex]\frac{0.000825}{0.098}[/tex]

Volume of HCl required to required to reach endpoint = 0.008418367 L

Volume of HCl required to required to reach endpoint = 8.418367 mL

Volume of HCl required to required to reach endpoint ≅ 8.42 mL

Hence, the volume of HCl required to required to reach endpoint is 8.42 mL

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Answer:

I think it might be:

NiO=2

CuO=4

BaO=2

Explanation:

Hope this helps.

Answer:

If the pH of a solution is less than 7, the solution is called acidic; if the pH is about 7, the solution is neutral; if the pH is greater than 7, the solution is is called basic. In an acidic solution, then, the concentration of hydrogen ions is greater than the concentration of hydroxide ions.

Explanation:

Not sure about the context of the question, but you can check with a ph scale tester.

Answer:

True

Explanation:

All irreversible reactions go to completion because the process cannot proceed in the backward direction.

A reversible reaction is one that does not go into completion in one direction.

An irreversible direction completely uses up the reactants to form the products and goes into completion.

These reactions can only proceed in one direction and not both.

Answer:

a

Explanation:

it's the most common thought of element when you need a compound from earth

Answer:

31.3grams

Explanation:

The amount of a radioactive element that remains, N(t), can be calculated by using the formula;

N(t) = N(o) × 0.5^{t/t(1/2)}

Where;

N(t) = mass of substance remaining

N(o) = mass of original substance

t(1/2) = half-life of substance

t = time elapsed

From the provided information; N(t) = ?, N(o) = 250g, t(1/2) = 1599 years, t = 4797 years

N(t) = 250 × 0.5^{4797/1599}

N(t) = 250 × 0.5^(3)

N(t) = 250 × 0.125

N(t) = 31.25g

N(t) = 31.3grams

.Answer:

.Marie Kondo

Answer:

Federal Government

Explanation:

:)))))))))

✌❤✌❤

Answer:

Cobalt/Electron configuration

Explanation:

[Ar] 3d7 4s2

Answer:

684

Explanation:

Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 684 g of lead would be required to make 119 grams of water.

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.

The balanced equation for the given reaction can be written as below

Pb + PbO[tex]_2[/tex] + 2H[tex]_2[/tex]SO[tex]_4[/tex] [tex]\rightarrow[/tex]2PbSO[tex]_4[/tex] + 2H[tex]_2[/tex]O

Mathematically,

The mole ratio between lead and water is 1:2

(119 g H2O) / (18.01532 g H2O/mol) x (1 mol Pb / 2 mol H2O) x (207.21 g Pb/mol) = 684 g Pb

The mass of lead comes out to be  684 g.

Therefore, 684 g of lead would be required to make 119 grams of water.

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Answer:

B. Sodium

Explanation:

The composition of sea water, smoke, and soft drinks are not consistent, and you can separate the parts that make up each. Sodium has a definite and consistent composition, so it is a pure substance.

Answer:

Unicellular organisms don't live as long and multicellular organisms. ... Disadvantages- Unicellular organisms only have one cell that is used to function their entire being. Short life span, can't grow lager then multicellular organisms.

HERE YA  GO FORTNITE KID

Answer:

liquid state is an intermediate phase between solid and gas phase

Answer is A. H20

Answer:

H2O

Explanation:

As H2 is a gas, and the question asks for the liquid state, it'd be H2O.

Answer:

I think it is chemical change

Answer:

In the electrolysis of dilute sulfuric acid, which electrolysis in aqueous solution to form hydrogen ions, H⁺, and sulfur IV ions SO₄²⁻ in the presence of H⁺ and OH⁻ ions from the water molecules

At the anode

The anode, positive electrode, attracts the negative OH⁻ and SO₄²⁻ ions where the OH⁻ gives up electrons to form water molecules and oxygen as follows;

4OH⁻ → 2H₂O + O₂ + 4e⁻

At the cathode

The positive H⁺ ions from the water molecules and the acid are attracted to the cathode where they combine with 2 electrons to form hydrogen gas as follows;

2e⁻ + 2H⁺ → H₂ (gas)

Explanation:

Answer:

Protons

Explanation:

Electrons have a negative charge which are found in shells around the nucleus. The nucleus consists of protons and neutron and the neutron has a neutral charge.

Answer:

b refraction

Explanation:

i saw on nasa's website lol

Answer:

Explanation:

uestion

If an atom of an element has a mass number of 45 and it has 20 neutrons in its nucleus, what is the atomic number of the

element?

Explanation:

element with atomic numbers 7 and 83 have 5 and 5 valence electrons

Answer:

3.1 moles of ammonia

18.67× 10²³ molecules

Mass = 52.7 g

Explanation:

Given data:

Number of atoms of hydrogen = 5.68×10²⁴ atoms

A) Number of molecules of ammonia = ?

Solution:

First of all we will calculate the number of moles of hydrogen.

1 mole = 6.022× 10²³ atoms

5.68×10²⁴ atoms × 1 mol / 6.022× 10²³ atoms

0.94×10¹ mol

9.4 moles of hydrogen

Moles of ammonia:

3 moles of hydrogen are present in one mole of ammonia.

9.4 moles of hydrogen = 1/3×9.4 =

3.1 moles of ammonia

Number of molecules of ammonia:

1 mole contain 6.022× 10²³ molecules.

3.1 mol × 6.022× 10²³ molecules / 1 mol

18.67× 10²³ molecules

c) Mass of sample = ?

Mass = number of moles × molar mass

Mass = 3.1 moles × 17 g/mol

Mass = 52.7 g

Answer:

beryllium has a higher ionization energy because its radius is smaller. boron has a higher ionization energy because its radius is smaller.

The final temperature : 79.07°C

Heat transferred can be formulated

Q=m.c.ΔT

Q= heat, J

m=mass,g

c=specific heat, for water 4.18 J/g C

ΔT = temperature

Heat transferred : 130 kcal

1 kcal = 4186 J

130 kcal =  

[tex]\tt 130\times 4186=544180~J[/tex]

mass = 2.5 kg =2500 g

t₁=27 °c

The final temperature :

[tex]\tt 544180=2500\times 4.18\times (t_2-27)\\\\t_2-27=52.07\\\\t_2=79.07^oC[/tex]

Answer:

Its B and D :)

Explanation:

I saw the answer key.

Answer:

weather

Explanation:

Answer:

slow

Explanation:

             according to kinetic molecular theory,as the temperature decreases the kinetic energy of molecules decreases

Answer:C - 3.115 g

Explanation:Correct