Which ones are false? need help please.

which of these pieces of equipment would be the most appropriate for precisely measuring 29 mL of liquid? Explain your reasoning

Anna007 [38]

Answer:

The best equipment would be the graduated cylinder. Why?

Firstly, the smallest marking on the graduated cylinder is 2 mL, while on all the others the smallest marking is way above that, like 25 mL and 100 mL.

Without even going into the details, we can first rule out the volumetric flask, since its smallest marking is 100 mL and even that is already bigger than our sample size, hence we would have no markings to accurately measure out 29 mL of our sample had we used the volumetric flask.

Next to be ruled out would be the Erlenmeyer flask, as you can see in the image, it only has three marking, and as the smallest marking is 25 mL, each marking is at least 25 mL, and even so far as going up to 50 mL. This cannot let us accurately measure 29 mL out at all, due to the markings being way too big to do that. Hence, the Erlenmeyer flask is ruled out.

Finally, the beaker seems to be a worthy candidate! Unfortunately, for the same reason as the Erlenmeyer flask, as you can see in the image each marking represents 10 mL. We cannot measure 9 mL in the beaker accurately, and hence the beaker is ruled too.

We are left with the graduated cylinder, and that is our answer.

Explanation:

Hope this helped!

5 0

3 years ago

It’s sometimes said that water is a “universal solvent.” Do a little research on this term. Why do some people call it this? Wha

Strike441 [17]

Water is called "universal solvent" because it is capable of dissolving various types of substances than any other solvent. The water's chemical composition such as its atoms that have a balance electrical charge and arrangement of polar makes it capable of dissociating different ionic compounds and balanced attraction to sodium and other elements, suitable to nature of any substances or life forms. However, this could be a problem in everyday life because given the title "universal solvent", it does not necessarily dissolve every compound. For example: water alone cannot be used in cleaning oils because it can't dissolve waxes and fats, and in dissolving large amounts of salt or sugar in our body.

4 0

4 years ago

Light bending as it passes through a rain drop is an example of... Question 11 options: Refraction Transmission Reflection Diffr

Karolina [17]

Hiya. Pretty sure it’s refraction

7 0

3 years ago

The prefab question someone help please !

lina2011 [118]

Answer: " 0.69 g / mL "

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Explanation:

______________________________________________

The "pre-lab question" given is:

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"The volume of an unknown liquid is 15 ml, and the mass of the liquid and the graduated cylinder it is in is 55.2g. If the mass of the graduated cylinder is 44.8g , what is the density of the unknown liquid? " .

____________________________________________

Note: The volume of the unknown liquid is 15 mL ; regardless of whether or not the "unknown liquid" is in the graduated cylinder.

The density of the unknown liquid is measured in: "g / mL " ;

that is, "grams per mL" .

____________________________________________

Note: "D = m / V " ; that is; "Density = mass/ volume" ;

that is: ["Density = mass per 'unit volume' ]" .

____________________________________________

So; to find the density, "D" , of the "unknown liquid" ; we would have to find the "mass" of the "unknown liquid" by "subtracting" :

the "known mass of liquid when the liquid is not in the cylinder"; that is: " 44.8g" ; From:

the "known combined value of the: 'mass of the liquid PLUS the mass of the cylinder" ; that is: "55.2g" ;

→ " 55.2g - 44.8g = 10.4g " .

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So: " D = m / V " ; (55.2g - 44.8 g) / 15 mL " ;

= (55.2g - 44.8 g) / 15 mL " ;

= (10.4g) / 15mL ;

____________________________________________

Note that the "Density" = mass per "unit volume" ;

→ So: D = m / V ; in units of: " g / mL " (grams per millileter) ;

= (10.4g) / 15mL ;

= [ (10.4) / 15 } g/ mL ;

= 0.693333333333333.... g / mL ;

→ We round to "2 (two) significant figures" ;

→ since we have: "10.4 g / 15 mL " ;

and 15 mL is considered a measured/experimental value;

and: 10.4g is considered a measured/experimental value;

→ so, the least precise value; 15 mL (has only 2 (two) significant figures ;

compared to other value: 10.4g (which has 3 (three) significant figures;

→ so we shall round off to 2 (two) significant figures:

= 0.69 g / mL

____________________________________________

→ which is our answer: " 0.69 g / mL " .

____________________________________________

3 0

3 years ago

How many oxygen atoms are in 1.90 g of quartz?

san4es73 [151]

The chemical formula for quartz is SiO₂. It has a molar mass of 60.08 g/mol. We use this to find the moles of quartz.

Moles of quartz = 1.90 g(1 mol/60.08 g) = 0.03162 moles

From the chemical formula, there are 2 moles of Oxygen per 1 mole of SiO₂.

Moles of oxygen = 0.03162 moles*2 = 0.063249 moles O

We use the Avogadro's number, 6.022×10²³ atoms/mole, to find the number of oxygen atoms.

0.063249 moles O * 6.022×10²³ atoms/mole = <em>3.81×10²² atoms of oxygen</em>

6 0

3 years ago