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Ymorist [56]
3 years ago
5

When a substance undergoes a chemical change its identity does not change true or false

Chemistry
1 answer:
quester [9]3 years ago
7 0
The answer is False....
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Suppose you combine two substances but no chemical reaction occurs. Which of the following best describes the result?
FromTheMoon [43]
What best describes the result is a mixture
7 0
3 years ago
Help plz:)))I’ll mark u Brainliest
4vir4ik [10]
Matter is anything that has mass and occupies space, It can exist in 3 states, or phases: solid, liquid, and gas.

Solid molecules are closely packed together and retain a fixed shape.

Liquid molecules aren't packed very closely, and take the shape of the bottom of the container.

Gas molecules are far apart and fill the container

completely.
7 0
2 years ago
Read 2 more answers
How many molecules of copper sulfate are needed to produce 5.0×1024 molecules of sodium sulfate?
lubasha [3.4K]

Answer:

5.0 × 10²⁴ molecules

Explanation:

Step 1: Write the balanced double displacement reaction

2 NaOH + CuSO₄ ⇒ Na₂SO₄ + Cu(OH)₂

Step 2: Calculate the moles corresponding to 5.0 × 10²⁴ molecules of Na₂SO₄

We will use Avogadro's number: there are 6.02 × 10²³ molecules in 1 mole of molecules.

5.0 × 10²⁴ molecule × 1 mol/6.02 × 10²³ molecule = 8.3 mol

Step 3: Calculate the moles of CuSO₄ required to produce 8.3 moles of Na₂SO₄

The molar ratio of CuSO₄ to Na₂SO₄ is 1:1. The moles of CuSO₄ required are 1/1 × 8.3 mol = 8.3 mol.

Step 4: Calculate the molecules corresponding to 8.3 moles of CuSO₄

We will use Avogadro's number.

8.3 mol × 6.02 × 10²³ molecule/1 mol = 5.0 × 10²⁴ molecule

4 0
3 years ago
Find [H+] of a 0.056 M hydrofluoric acid solution. Ka = 1.45 x 10-7
brilliants [131]

Answer:  [H^+] of 0.056 M HF solution is 8.96\times 10^{-5}

Explanation:

HF\rightarrow H^+F^-

 cM              0             0

c-c\alpha        c\alpha          c\alpha  

So dissociation constant will be:

K_a=\frac{(c\alpha)^{2}}{c-c\alpha}

Give c= 0.056 M and \alpha = ?

K_a=1.45\times 10^{-7}

Putting in the values we get:

1.45\times 10^{-7}=\frac{(0.056\times \alpha)^2}{(0.056-0.056\times \alpha)}

(\alpha)=0.0016

[H^+]=c\times \alpha

[H^+]=0.056\times 0.0016=8.96\times 10^{-5}  

Thus [H^+] of 0.056 M HF solution is 8.96\times 10^{-5}

8 0
3 years ago
The pH of a 0.150 molar solution of a weak acid is 4.10. What is the pKa of the acid?
Kamila [148]
Answer: 4.21×10⁻⁸

Explanation:


1) Assume a general equation for the ionization of the weak acid:

Let HA be the weak acid, then the ionization equation is:

HA ⇄ H⁺ + A⁻

2) Then, the expression for the ionization constant is:

Ka = [H⁺][A⁻] / [HA]

There, [H⁺] = [A⁻], and [HA] = 0.150 M (data given)


3) So, you need to determine [H⁺] which you do from the pH.

By definition, pH = - log [H⁺]

And from the data given pH = 4.1


⇒ 4.10 = - log [H⁺] ⇒ [H⁺] = antilog (- 4.10) = 7.94×10⁻⁵

4) Now you have all the values to calculate the expression for Ka:

ka = 7.94×10⁻⁵ × 7.94×10⁻⁵ / 0.150 = 4.21×10⁻⁸
3 0
3 years ago
Read 2 more answers
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