A sample of gold has a mass of 67.2 g and a volume of 3.5 cm3. the density of gold is

The laser in a 3D printer uses light with a frequency of 3.844 × 1014 Hz. Calculate the wavelength of this light in nm. Show all

Natali5045456 [20]

Answer:

The wavelength of this light is 780.4 nm.

Explanation:

Given that,

The frequency of laser light, $f=3.844 \times 10^{14}\ Hz$

We need to find the wavelength of this light.

We know that,

$c=f\lambda$

Where

$\lambda$ is the wavelength of light

So,

$\lambda=\dfrac{c}{f}\\\\\lambda=\dfrac{3\times 10^8}{3.844 \times 10^{14}}\\\\=7.804\times 10^{-7}\ m\\\\=780.4\ nm$

So, the wavelength of this light is 780.4 nm.

5 0

3 years ago

Where on the periodic table are the metals found?

White raven [17]

On the left side. The alkali metals are group 1, the alkaline earth metals are group 2, and the transition metals are groups 3-12.

6 0

4 years ago

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In the reaction, Zn(s) + 2 HCl(aq) --> ZnCl2 (aq)+ H2(g), 25 grams of Zn are reacted with 17.5 g of HCl. How many grams of H2

Gennadij [26K]

Answer:

0.480 g of H₂ are produced, in the reaction.

Explanation:

This is the reaction:

Zn(s) + 2HCl → ZnCl₂ (aq) + H₂ (g)

We havethe mass of both reactants, so we must work with them to find out the limiting reactant and then, determine the amount of H₂ produced.

Let's convert the mass to moles ( mass / molar mass)

25 g / 65.41 g/mol = 0.382 moles Zn

17.5 g / 36.45 g/mol = 0.480 moles HCl

Ratio is 1:2, so 1 mol of Zn react with the double of moles of HCl.

0.382 moles of Zn would need the double of moles to react, so (0.382 .2) = 0.764 moles of HCl. → We only have 0.480 moles, so the acid is the limiting.

Now let's determine the moles of H₂ formed.

Ratio is 2:1, so If i take account the moles I have, I will produce the half of moles of my product.

0.480 moles / 2 = 0.240 moles of H₂ are produced.

To find out the mass, we must multiply mol . molar mass

0.240 mol . 2g/mol = 0.480 g

3 0

3 years ago

Consider a mixture of NaCl and NaNO3 that is 31.8% Na by mass. Calculate the percentage by mass of NaCl in the mixture.

lutik1710 [3]

Answer: The percentage by mass of NaCl in the mixture is 38.5 %

Explanation:

To calculate the mass percentage of element in compound, we use the equation:

$\text{Mass percent of element}=\frac{\text{Mass of element}}{\text{Mass of compound}}\times 100$ .......(1)

For NaCl:

Mass of sodium element = 23 g

Mass of NaCl = 58.5 g

Putting values in equation 1, we get:

$\text{Mass percent of sodium element}=\frac{23g}{58.5g}\times 100=39.32\%$

Mass fraction of sodium metal in NaCl = 0.3932

For $NaNO_3$ :

Mass of sodium element = 23 g

Mass of $NaNO_3$ = 85 g

Putting values in equation 1, we get:

$\text{Mass percent of sodium element}=\frac{23g}{85g}\times 100=27.1\%$

Mass fraction of sodium metal in sodium nitrate = 0.271

Let us assume the mass fraction of NaCl in the mixture is 'x'

So, the mass fraction of $NaNO_3$ in the mixture will be '(1-x)'

We are given:

Percent by mass of Na in the mixture = 31.8 %

Mass fraction of Na in the mixture = 0.318

Evaluating the mass fraction of NaCl in the mixture:

$[(x\times 0.3932)+((1-x)\times 0.271)]=0.318$

x = 0.385

Percent by mass of NaCl in the mixture will be = $(0.385\times 100)=38.5\%$

Hence, the percentage by mass of NaCl in the mixture is 38.5 %

4 0

3 years ago

Absolute proof about the origin of a crater on the moon or the "star of Bethlehem" cannot be determined

IgorC [24]

Your answer is False love!

8 0

3 years ago

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