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4 years ago

On the pH scale, a 7 indicates _____. a base an acid neutrality

Chemistry

1 answer:

worty [1.4K]4 years ago

3 0

The correct answer is:

neutrality

on the pH scale 7 is neutral above 7 is basic and below 7 is acidic.

Explanation:

The pH is an example of how acidic/basic water is. The scale goes from 0 - 14, with 7 being neutral, pH of less than 7 designates acidity, whereas a pH of greater than 7 intimates a base. pH is really a pattern of the relative amount of free hydrogen and hydroxyl ions in the water.pH is a measure of how acidic/basic water is.

It is neutral because, at this pH, the molar concentrations of Hydroxide and Hydronium are same, therefore the substance is not a base nor an acid.

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Which of the following is an example of CHEMICAL weathering? (select all

larisa86 [58]

Rust on a rock that contains iron
Mineral absorbs water and changes into a new substance

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3 years ago

write down the balanced chemical equation of the reaction that takes place between iron and concentrated sulphuric acid

pishuonlain [190]

Answer:

2Fe + 3H2SO4 → Fe2(SO4)3 + 3H2

Explanation:

Iron is a metallic element with chemical symbol, Fe while concentrated sulphuric acid is a chemical compound with chemical formula, H2SO4. Both are involved in a chemical reaction as follows:

Fe + H2SO4 → Fe2(SO4)3 + H2

However, this reaction is not balanced as the number of moles of each atom in both the reactants and product side is not equal. To balance the equation, we have to ensure that each number of atom is equal. The balanced equation are as follows:

2Fe + 3H2SO4 → Fe2(SO4)3 + 3H2

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3 years ago

The element europium exists in nature as two isotopes: 151eu has a mass of 150.9196 amu, and 153eu has a mass of 152.9209 amu. t

Ratling [72]

Two isotopes of europium are 151eu and 153eu

Mass of 151eu = 150.9196 amu

Mass of 153eu = 152.9209 amu

Average atomic mass = 151.96 amu

Let x and y are the relative abundance of two isotopes of europium are 151eu and 153eu

So, x% times 150.9196 + y% times 152.9209 = 151.96

x150.9196 + y152.9209 = 151.96

And x + y = 100% = 1, from here x = 1 – y and y = 1 - x

Solve these equation by substitution,

By replacing x = 1-y, we get

(1-y)150.9196 + y152.9209 = 151.96

150.9196 – 150.9196y + y152.9209 = 151.96

2.0013y = 1.0404

Y =0.5199 = 51.99%

Using the value of y we get,

X = 1-y = 1-51.99 = 0.4801 = 48.01%

So, relative abundance of two isotopes of europium are 151eu and 153eu are 48.01% and 51.99% respectively

6 0

3 years ago

Read 2 more answers

When 0.422g of phosphorus is burned, 0.967g of a white oxide is obtained.

nata0808 [166]

Moles = mass / molar mass

moles P = 0.422 g / 30.97 g/mol = 0.01363 mol 
moles O = (0.967 g - 0.422g) / 16.00 g/mol = 0.03406 moles 

So ratio moles P : moles O 
= 0.01363 mol : 0.03406 mol 

Divide each number in the ratio by the smallest number 

(0.01363 / 0.01363) : (0.03406 / 0.01363) 
= 1 : 2.5 

The empirical formula needs to be the smallest whole number ratio of atoms in the molecules. Since you have a non-whole number, multiply the ratio by the smallest number needed to make both number whole numbers. In this case x 2 

2 x (1 : 2.5) 
= 2 : 5

5 0

3 years ago

Read 2 more answers

To measure the amount of citric acid (C3 H, oHn a certain candy, an analytical chemist dissolves a 16.00 g sample of the candy i

Naily [24]

Answer:

Acid-Base reaction (the reactanct acting as a base is NaOH)

mass percent = 1.93%

Explanation:

The reaction that takes place is:

C₃H₅O(CO₂H)₃(aq) + 3OH⁻ (aq) → C₃H₅O(CO₂)₃⁻³(aq) + 3H₂O(l)

This is a acid-base reaction, with the citric acid acting as the acid and the sodium hydroxide NaOH acting as the base.

We calculate the moles of citric acid using the information from the titration:

0.0142 L * 0.340 M * $\frac{1molAcid}{3molOH^{-}}$ = 1.609x10⁻³ mol citric acid

Now we convert moles to mass using the acid's molecular weight (192.13g/mol):

1.609x10⁻³ mol citric acid * 192.13g/mol = 0.3092 g citric acid

Finally we calculate the mass percent of citric acid in the sample:

0.3092 g / 16.00 g * 100% = 1.93%

3 0

3 years ago