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3 years ago

Methods scientist use to determine a change in physical or chemical change in an Item

1 answer:

8 0

They'd observe any new substances or new color, and temp. that is irreversible.

If this helped and you have any other questions, feel free to comment on my wall. Hope this helped.

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After air enter the body through the nose or mouth it then goes to the what?

spin [16.1K]

Answer:

your lungs

Explanation:

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3 years ago

At STP, adding salt to a 200 mL sample of water produces a saturated 1.7 M solution. How many grams of salt (NaCl) must be added

Illusion [34]

Answer:

$m_{NaCl}=19.9gNaCl$

Explanation:

Hello!

In this case, since the formula for the calculation of molarity is:

$M=\frac{n}{V}$

Whereas we can compute the moles of the solute as shown below, making sure the volume is in liters:

$n=M*V$

Thus, by plugging in we obtain:

$n=0.200L*1.70mol/L=0.170molNaCl$

Next, since the molar mass of NaCl is 58.44 g/mol, we obtain the following mass:

$m_{NaCl}=0.170molNaCl*\frac{58.44gNaCl}{1molNaCl}\\\\m_{NaCl}=19.9gNaCl$

Best regards!

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3 years ago

How many grains are in spaghetti

MissTica

Answer:

100,284,896

Explanation:

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3 years ago

Help which one will it be

salantis [7]

Answer:

Explanation:

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3 years ago

Read 2 more answers

A government laboratory wants to determine whether water in a certain city has any traces of fluoride and whether the concentrat

nexus9112 [7]

Answer: The given sample of water is not safe for drinking.

Explanation:

We are given:

Concentration of fluorine in water recommended = 4.00 ppm

ppm is the amount of solute (in milligrams) present in kilogram of a solvent. It is also known as parts-per million.

To calculate the ppm of fluorine in water, we use the equation:

$\text{ppm}=\frac{\text{Mass of solute}}{\text{Mass of solution}}\times 10^6$

Both the masses are in grams.

We are given:

Mass of fluorine = $0.152mg=0.152\times 10^{-3}g$ (Conversion factor: 1 g = 1000 mg)

Mass of water = 5.00 g

Putting values in above equation, we get:

$\text{ppm of fluorine in water}=\frac{0.152\times 10^{-3}}{5}\times 10^6\\\\\text{ppm of fluorine in water}=30.4$

As, the calculated concentration is greater than the recommended concentration. So, the given sample of water is not safe for drinking.

Hence, the given sample of water is not safe for drinking.

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3 years ago