Approximately ____ days have passed when 20% of Cobalt (Co) remains? A) 19 B) 20 C) 21 D) 29

PLEASE HELP ME I HAVE NO IDEA “Heat (thermal) energy is being applied to the substance whenever the Bunsen Burner is on. Before

svetlana [45]

TLDR: The energy was being used simply to heat the substance up.

Whenever something melts, it performs what is called a "phase transition", where the state of matter moves from one thing to something else. You can see this in your iced drink at lunch; as the ice in the cup of liquid heats up, it reaches a point where it will eventually "change phase", or melt. The same can be achieved if you heat up that water enough, like if you're cooking; when you boil eggs, the water has so much thermal energy it can "change phase" and become a gas!

However, water doesn't randomly become a boiling gas, it has to heat up for a while before it reaches that temperature. For a real-life example, the next time you cook something, hold you hand above the water before it starts boiling. You'll see that that water has quite a high temperature despite not boiling.

There's a lot of more complex chemistry to describe this phenomena, such as the relationship between the temperature, pressure, and what is called the "vapor pressure" of a liquid when describing phase changes, but for now just focus on the heating effect. When ice melts, it doesn't seem like its heating up, but it is. The ice absorbs energy from its surroundings (the warmer water), thus heating up the ice and cooling down the water. Similarly, the bunsen burner serves to heat up things in the lab, so before the solid melts in this case it was simply heating up the solid to the point that it could melt.

Hope this helps!

5 0

3 years ago

In which circumstance is displacement the same as distance traveled?

Ede4ka [16]

Distance travelled will be equal to displacement when the line drawn is completely straight.

Hopefully, this helps.

8 0

2 years ago

Read 2 more answers

10. Liquid changing to gas only at the surface is called

mina [271]

Answer:

Evaporation

Explanation:

Though it doesn't require high temperatures to do so

3 0

2 years ago

In a titration, 4.7 g of an acid (HX) requires 32.6 mL of 0.54 M NaOH(aq) for complete reaction. What is the molar mass of the a

katrin2010 [14]

Answer : The molar mass of an acid is 266.985 g/mole

Explanation : Given,

Mass of an acid (HX) = 4.7 g

Volume of NaOH = 32.6 ml = 0.0326 L

Molarity of NaOH = 0.54 M = 0.54 mole/L

First we have to calculate the moles of NaOH.

$\text{Moles of }NaOH=\text{Molarity of }NaOH\times \text{Volume of solution}=0.54mole/L\times 0.0326L=0.017604mole$

Now we have to calculate the moles of an acid.

In the titration, the moles of an acid will be equal to the moles of NaOH.

Moles of an acid = Moles of NaOH = 0.017604 mole

Now we have to calculate the molar mass of and acid.

$\text{Moles of an acid}=\frac{\text{Mass of an acid}}{\text{Molar mass of an acid}}$

Now put all the given values in this formula, we get:

$0.017604mole=\frac{4.7g}{\text{Molar mass of an acid}}$

$\text{Molar mass of an acid}=266.985g/mole$

Therefore, the molar mass of an acid is 266.985 g/mole

3 0

3 years ago

As with other ionic compounds, potassium bromate, KBrO3, dissociates into ions when it dissolves in water. If 13.8 g of KBrO3 is

chubhunter [2.5K]

Answer:

ΔH of dissociation is 38,0 kJ/mol

Explanation:

The dissociation reaction of KBrO₃ is:

KBrO₃ → K⁺ + BrO₃⁻ 

This dissolution consume heat that is evidenced with the decrease in water temperature.

The heat consumed is:

q = CΔTm

Where C is specific heat of water (4,186 J/mol°C)

ΔT is the temperature changing (18,0°C - 13,0°C = 5,0°C)

And m is mass of water (150,0 mL ≈ 150,0 g)

Replacing, heat consumed is:

q = 3139,5 J ≡ 3,14 kJ

13,8 g of KBrO₃ are:

13,8 g×(1mol/167g) = 0,0826 moles

Thus, ΔH of dissociation is:

3,14kJ / 0,0826mol = 38,0 kJ/mol

I hope it helps!

3 0

2 years ago