If the room temperature is often expressed at 300K. What is the temperature in Celsius?

Jailah needs a replacement for lithium for a science experiment. She tries silicon, but it does not work. Using what you know ab

pentagon [3]

Answer:

C

Explanation:

6 0

3 years ago

What is the (a) frequency and (b) wavelength (in nm) of a source of purple light at the edge of the visible light spectrum?

stiv31 [10]

Answer: a) $Frequency=666\times10^{12}Hz-789\times10^{12}Hz$

b) $Wavelength=380nm-450nm$

Explanation: Visible light is a form of electromagnetic wave.

Wavelength is defined as the distance between two successive crests of a wave. It is represented as symbol $\lambda$ .

Frequency is defined as the number of complete cycles happening per second. It is represented by the symbol $\nu$ .

Wavelength and Frequency follow inverse relation,

$\nu=\frac{c}{\lambda}$

where, c = speed of light = $3\times10^8m/s$

Wavelength and frequency of a wave is usually expressed in a range.

a) $\text{Frequency of visible light}=666\times10^{12}Hz-789\times10^{12}Hz$

b) $\text{Wavelength of visible light}=380nm-450nm$

7 0

3 years ago

Which statement correctly describes diamond and graphite, which are different forms of solid carbon?

mart [117]

They differ in their molecular structures and properties.

5 0

3 years ago

Read 2 more answers

Which properties of a substance could change during a<br> PHYSICAL change?

olga2289 [7]

It’s appearance
It’s physical form
What it feels like
How hot it gets
If it melts
Shape
Color

4 0

2 years ago

In science, we like to develop explanations that we can use to predict the outcome of events and phenomena. Try to develop an ex

Kay [80]

The question is incomplete. The complete question is :

In science, we like to develop explanations that we can use to predict the outcome of events and phenomena. Try to develop an explanation that tells how much NaOH needs to be added to a beaker of HCl to cause the color to change. Your explanation can be something like: The color change will occur when [some amount] of NaOH is added because the color change occurs when [some condition]. The goal for your explanation is that it describes the outcome of this example, but can also be used to predict the outcome of other examples of this phenomenon. Here's an example explanation: The color of the solution will change when 40 ml of NaOH is added to a beaker of HCl because the color always changes when 40ml of base is added. Although this explanation works for this example, it probably won't work in examples where the flask contains a different amount of HCl, such as 30ml. Try to make an explanation that accurately predicts the outcome of other versions of this phenomenon.

Solution :

Consider the equation of the reaction between NaOH and $HCl$

NaOH (aq) + HCl (aq) → NaCl(aq) + $H_2O (l)$

The above equation tells us that $1 \text{mole}$ of $NaOH$ reacts with $1 \text{mole}$ of $HCl$ .

So at the equivalence point, the moles of NaOH added = moles of $HCl$ present.

If the volume of the $HCl$ taken = $V_1$ mL and the conc. of $HCl$ = $M_1$ mole/L

The volume of NaOH added up to the color change = $V_2 \text{ and conc of NaOH = M}_2$ mole/L

Moles of $HCl$ taken = $V_1 \ mL \times M_1 \ mol/100 \ mL = V_2M_2 \times 10^{-3}$ moles.

The color change will occur when the moles of NaOH added is equal to the moles of $HCl$ taken.

Thus when $V_1 M_1 \times 10^{-3} = V_2M_2 \times 10^{-3}$

or when $V_1M_1 = V_2M_2$

or $V_2=\frac{V_1M_1}{M_2}$ mL of NaOH added, we observe the color change.

Where $V_1, M_1$ are the volume and molarity of the $HCl$ taken.

$M_2$ is the molarity of NaOH added.

When both the NaOH and $HCl$ are of the same concentrations, i.e. if $M_1=M_2$ , then $V_2=V_1$

Or the 40 mL of $HCl$ will need 40 mL of NaOH for a color change and

30 mL of $HCl$ would need 30 mL of NaOH for the color change (provided the concentration $M_1=M_2$ )

7 0

2 years ago