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babymother [125]

3 years ago

13

What does it mean when there is a physical change?

1 answer:

stiks02 [169]3 years ago

3 0

Answer:

The matter has changed size, shape, or form.

Explanation:

A new substance that is formed is creation.

if the matter changed from one substance to another this is called a chemical reaction.

Surely not. It won't change the molecular level.

Hope that helps.

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A 360. g iron rod is placed into 750.0 g of water at 22.5°C. The water temperature rises to 46.7°C. What was the initial tempera

Grace [21]

Answer: The initial temperature of the iron was $515^0C$

Explanation:

$heat_{absorbed}=heat_{released}$

As we know that,

$Q=m\times c\times \Delta T=m\times c\times (T_{final}-T_{initial})$

$m_1\times c_1\times (T_{final}-T_1)=-[m_2\times c_2\times (T_{final}-T_2)]$ .................(1)

where,

q = heat absorbed or released

$m_1$ = mass of iron = 360 g

$m_2$ = mass of water = 750 g

$T_{final}$ = final temperature = $46.7^0C$

$T_1$ = temperature of iron = ?

$T_2$ = temperature of water = $22.5^oC$

$c_1$ = specific heat of iron = $0.450J/g^0C$

$c_2$ = specific heat of water= $4.184J/g^0C$

Now put all the given values in equation (1), we get

$-360\times 0.450\times (46.7-x)=[750\times 4.184\times (46.7-22.5)]$

$T_i=515^0C$

Therefore, the initial temperature of the iron was $515^0C$

4 0

3 years ago

Help please! please answer with a good answer

KonstantinChe [14]

Answer:

what the heck what is that?

Explanation:

5 0

3 years ago

Need help figuring out these questions did I do them right

Bas_tet [7]

Answer:

The answer to your question is: more less

Explanation:

I suggest you these answers:

a) PCl₅ (s) ⇒ PCl₃ (s) + Cl₂ (g)

b) ZnBr₂ (aq) + Li₃CO₃ (aq) ⇒ ZnCO₃ (s) + LiBr (aq)

c) C₂H₄ + O₂ ⇒ CO₂ (g) + H₂O (l)

Do you have to balance them?

8 0

3 years ago

Calculate the pH of a solution that is 0.235M benzoic acid and 0.130M sodium benzoate, a salt whose anion is the conjugate base

lesantik [10]

Hello!

We have the following data:

ps: we apply Ka in benzoic acid to the solution.

[acid] = 0.235 M (mol/L)

[salt] = 0.130 M (mol/L)

pKa (acetic acid buffer) =?

pH of a buffer =?

Let us first find pKa of benzoic acid, knowing that Ka (benzoic acid) = $6.20*10^{-5}$

So:

$pKa = - log\:(Ka)$

$pKa = - log\:(6.20*10^{-5})$

$pKa = 5 - log\:6.20$

$pKa = 5 - 0.79$

$\boxed{pKa = 4.21}$

Now, using the abovementioned data for the pH formula of a buffer solution or (Henderson-Hasselbalch equation), we have:

$pH = pKa + log\:\dfrac{[salt]}{[acid]}$

$pH = 4.21 + log\:\dfrac{0.130}{0.235}$

$pH = 4.21 + log\:0.55$

$pH = 4.21 + (-0.26)$

$pH = 4.21 - 0.26$

$\boxed{\boxed{pH = 3.95}}\end{array}}\qquad\checkmark$

Note:. The pH <7, then we have an acidic solution.

I Hope this helps, greetings ... DexteR! =)

8 0

2 years ago

What is an orderly, three dimensional arrangement formed by ions called?

Morgarella [4.7K]

I believe it is a crystal, read it in a chemistry book over last summer so might be off

3 0

3 years ago