1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
gulaghasi [49]
2 years ago
8

The elements Beryllium (Be), Magnesium (Mg), Calcium (Ca) and Strontium (Sr) are all what?

Chemistry
1 answer:
AVprozaik [17]2 years ago
4 0

answer : alkaline earth metals ..

You might be interested in
Which of the following represents a chemical property of hydrogen gas?
Hoochie [10]

Answer: The option that represents the chemical properties of Hydrogen gas is A (It explodes with a flame.)

Explanation: Hydrogen gas is the lightest of all gases and the most abundant element in the universe. It's physical and chemical properties are the characteristics that distinguishes it from any other substance.

chemical properties of Hydrogen are the characteristics that determine how it will react with other substances or change from one substance to another. They include:

-It burns in air or oxygen to produce water.

-When mixed with air it can spontaneously explode by spark, flame or sunlight. I hope this helps. thanks.

4 0
3 years ago
My question is what is a cell?
frez [133]

The smallest functional and structural unit of an organism, usually microscopic and consisting of cytoplasm and a nucleus in a membrane.

5 0
3 years ago
In CaSO4, the oxidation number of Ca is<br> that of S is<br> and that of O is
Assoli18 [71]

Answer: In CaF2, the oxidation number of Ca is +2

, and that of F is -1

. In H2SO4, the oxidation number of H is +1

, that of S is +6

, and that of O is -2

. In CaSO4, the oxidation number of Ca is +2

, that of S is +6

, and that of O is -2

. In HF, the oxidation number of H is +1

, and that of F is -1

7 0
3 years ago
6. A 25.0-mL sample of 0.125 M pyridine is titrated with 0.100 M HCI. Calculate the pH
Vadim26 [7]

Answer:

a) pH = 9.14

b) pH = 8.98

c) pH = 8.79

Explanation:

In this case we have an acid base titration. We have a weak base in this case the pyridine (C₅H₅N) and a strong acid which is the HCl.

Now, we want the know the pH of the resulting solution when we add the following volume of acid: 0, 10 and 20.

To know this, we first need to know the equivalence point of this titration. This can be known using the following expression:

M₁V₁ = M₂V₂  (1)

Using this expression, we can calculate the volume of acid required to reach the equivalence point. Doing that we have:

M₁V₁ = M₂V₂

V₁ = M₂V₂ / M₁

V₁ = 0.125 * 25 / 0.1 = 31.25 mL

This means that the acid and base will reach the equivalence point at 31.25 mL of acid added. So, the volume of added acid of before, are all below this mark, so we can expect that the pH of this solution will be higher than 7, in other words, still basic.

To know the value of pH, we need to apply the following expression:

pH = 14 - pOH  (2)

the pOH can be calculated using this expression:

pOH = -log[OH⁻]  (3)

The [OH⁻] is a value that can be calculated when the pyridine is dissociated into it's ion. However, as this is a weak acid, the pyridine will not dissociate completely in solution, instead, only a part of it will be dissociated. Now, to know this, we need the Kb value of the pyridine.

The reported Kb value of the pyridine is 1.5x10⁻⁹ so, with this value we will do an ICE chart for each case, and then, calculate the value of the pH.

<u>a) 0 mL of acid added.</u>

In this case, the titration has not begun, so the concentration of the base will not be altered. Now, with the Kb value, let's write an ICE chart to calculate the [OH⁻], the pOH and then the pH:

       C₅H₅N + H₂O <-------> C₅H₅NH⁺ + OH⁻     Kb = 1.5x10⁻⁹

i)       0.125                                0             0

e)        -x                                   +x           +x

c)      0.125-x                              x             x

Writting the Kb expression:

Kb = [C₅H₅NH⁺] [OH⁻] / [C₅H₅N]    replacing the values of the chart:

1.5x10⁻⁹ = x² / 0.125-x --> Kb is really small, so we can assume that x will be very small too, and 0.125-x can be neglected to only 0.125, and then:

1.5x10⁻⁹ = x² / 0.125

1.5x10⁻⁹ * 0.125 = x²

x = [OH⁻] = 1.37x10⁻⁵ M

Now, we can calculate the pOH:

pOH = -log(1.37x10⁻⁵) = 4.86

Finally the pH:

pH = 14 - 4.86

<h2>pH = 9.14</h2>

<u>b) 10 mL of acid added</u>

In this case the titration has begun so the acid starts to react with the base, so we need to know how many moles of the base remains after the volume of added acid:

moles acid = 0.1 * (0.010) = 1x10⁻³ moles

moles base = 0.125 * 0.025 = 3.125x10⁻³

This means that the base is still in higher quantities, and the acid is the limiting reactant here, so the remaining moles will be:

remaining moles of pyridine = 3.125x10⁻³ - 1x10⁻³ = 2.125x10⁻³ moles

The concentration of pyridine in solution:

[C₅H₅N] = 2.125x10⁻³ / (0.025 + 0.010) = 0.0607 M

Now with this concentration, we will do the same procedure of before, with the ICE chart, but replacing this new value of the base, to get the [OH⁻] and then the pH:

        C₅H₅N + H₂O <-------> C₅H₅NH⁺ + OH⁻     Kb = 1.5x10⁻⁹

i)       0.0607                             0             0

e)        -x                                   +x           +x

c)      0.0607-x                           x             x

Writting the Kb expression:

Kb = [C₅H₅NH⁺] [OH⁻] / [C₅H₅N]    replacing the values of the chart:

1.5x10⁻⁹ = x² / 0.0607-x --> 0.0607

1.5x10⁻⁹ = x² / 0.0607

1.5x10⁻⁹ * 0.0607 = x²

x = [OH⁻] = 9.54x10⁻⁶ M

Now, we can calculate the pOH:

pOH = -log(9.54x10⁻⁶) = 5.02

Finally the pH:

pH = 14 - 5.02

<h2>pH = 8.98</h2>

<u>c) 20 mL of acid added:</u>

In this case the titration it's almost reaching the equivalence point and the acid is still reacting with the base, so we need to know how many moles of the base remains after the volume of added acid:

moles acid = 0.1 * (0.020) = 2x10⁻³ moles

moles base = 0.125 * 0.025 = 3.125x10⁻³

This means that the base is still in higher quantities, and the acid is the limiting reactant here, so the remaining moles will be:

remaining moles of pyridine = 3.125x10⁻³ - 2x10⁻³ = 1.125x10⁻³ moles

The concentration of pyridine in solution:

[C₅H₅N] = 1.125x10⁻³ / (0.025 + 0.020) = 0.025 M

Now with this concentration, we will do the same procedure of before, with the ICE chart, but replacing this new value of the base, to get the [OH⁻] and then the pH:

        C₅H₅N + H₂O <-------> C₅H₅NH⁺ + OH⁻     Kb = 1.5x10⁻⁹

i)       0.025                                0             0

e)        -x                                   +x           +x

c)      0.025-x                             x             x

Writting the Kb expression:

Kb = [C₅H₅NH⁺] [OH⁻] / [C₅H₅N]    replacing the values of the chart:

1.5x10⁻⁹ = x² / 0.025-x --> 0.025

1.5x10⁻⁹ = x² / 0.025

1.5x10⁻⁹ * 0.025 = x²

x = [OH⁻] = 6.12x10⁻⁶ M

Now, we can calculate the pOH:

pOH = -log(6.12x10⁻⁶) = 5.21

Finally the pH:

pH = 14 - 5.21

<h2>pH = 8.79</h2>
5 0
3 years ago
Which chemical family tends to get rid of electrons by forming a compound
lisov135 [29]

Answer:

group 1, 2 and 3 tend to get rid of electrons and start to form compounds with groups 7, 6, and 5.

Explanation:

7 0
3 years ago
Other questions:
  • There are six kingdoms of living things. Archaebacteria is one of these kingdoms. Which of the following are also kingdoms of li
    13·2 answers
  • Choose all that apply. Solids, liquids, and gases can be distinguished by their:molecular weight shape temperature kinetic energ
    11·1 answer
  • A partially-enclosed coastal region where sea water mixes with freshwater is called a(n) _______.
    14·1 answer
  • This type of triglyceride contains more than one double bond in the fatty acid carbon atoms
    15·1 answer
  • a dog is trained to sit and shake hands. These traits are most likely? a. inherited b. not inherited c. not acquired d. innate
    15·1 answer
  • A student dips a strip of metal into a liquid. Which is evidence that only a physical change has occurred? The metal bends more
    7·2 answers
  • Calculate the mass of 9.75x1021 atoms of helium.
    12·1 answer
  • Which statement best describes a possible way that
    14·1 answer
  • Help would be appreciated please!
    15·2 answers
  • What is the mass of 1.75 moles of HF?
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!