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sp2606 [1]
3 years ago
11

Which elements do hydrogen fuel cells combine to produce electricity? (9TH GRADE SCIENCE)

Chemistry
1 answer:
Andrej [43]3 years ago
5 0
<span>it will convert the energy produced by a chemical reaction into usable electric power.</span>
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The titration of Na2CO3 with HCl has the following qualitative profile: a. Identify the major species in solution at points A-F.
exis [7]

Answer:

Answer is explained in the explanation section below.

Explanation:

Solution:

Note: This question is incomplete and lacks very important data to solve this question. But I have found the similar question which shows the profiles about which question discusses. Using the data from that question, I have solved the question.

a) We need to find the major species from A to F.

Major Species at A:

1. Na_{2} CO_{3}

Major Species at B:

1. Na_{2} CO_{3}

2. NaHCO_{3}

Major Species at C:

1. NaHCO_{3}

Major Species at D:

1. NaHCO_{3}

2. H_{2}CO_{3}

Major Species at E:

1. H_{2}CO_{3}

Major Species at F:

1. H_{2}CO_{3}

b) pH calculation:

At Halfway point B:

pH = pKa_{1} + log[CO_{3}.^{-2}]/[HCO_{3}.^{-1}]

pH = pKa_{1} = 6.35

Similarly, at halfway point D.  

At point D,

pH = pKa_{2} + log [HCO_{3}.^{-1}]/[H2CO_{3}]

pH = pKa_{2} = 10.33

8 0
3 years ago
Help me please :3 :3 :3 ;3
Alona [7]
I think the answer is C.
8 0
3 years ago
The ionization constant (Ka) of HF is 6.7 X 10 ^-4. Which of the following is true in a 0.1 M solution of this acid?
spin [16.1K]
The ionization equation is:

HF ⇄ H(+) + F(-)

The ionization constant is Ka = [H(+)] * [H(-)] / [HF]

=> [H(+)] * [F(-)] = Ka * [HF]

Given that Ka < 1

[H(+)] * [F(-)] < [HF]

Which is [HF] >  [H(+)] * [F(-)] the option a. fo the list of choices.
8 0
2 years ago
Read 2 more answers
2. Extract the relevant information from the question: NaOH V = 30 mL , M = 0.10 M HCl V = 25.0 mL, M = ?
Andrei [34K]

Answer:

0.12M

Explanation:

A balanced equation for the reaction will go a great deal in obtaining our desired result. So, let us write a balanced equation for the reaction

HCl + NaOH —> NaCl + H2O

From the above equation,

nA (mole of the acid) = 1

nB (mole of the base) = 1

Data obtained from the question include:

Vb (volume of the base) = 30mL

Mb (Molarity of the base) = 0.1M

Va (volume of the acid) = 25mL

Ma (Molarity of the acid) =?

The molarity of the acid can be obtained as follow:

MaVa/MbVb = nA/nB

Ma x 25/ 0.1 x 30 = 1

Cross multiply to express in linear form

Ma x 25 = 0.1 x 30

Divide both side by 25

Ma = (0.1 x 30) / 25

Ma = 0.12M

The molarity of the acid is 0.12M

5 0
3 years ago
Question 9 rank the effective nuclear charge z * experienced by a valence electron in each of these atoms:
AlexFokin [52]
To rank the effective nuclear charge Z* experienced by a valence electrons of a set of atoms that belong to a same period, you only need to apply the rule of trend: it increases as you move from left to right in the period.

So, lets do it for these atoms: P,  Al, Si, Cl

The belong to a same period and the order is Al, Si, P, Cl (just see a periodic table). So the rank is Al < Si < P < Cl

Now, lets do it for these atoms:, Be, Ne, O, C

They belong to the second period. The order is Be, C, O, Ne

So, the rank is Be < C < O < Ne.


7 0
3 years ago
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