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3 years ago

The steps in every scientific investigation must_______________________.

Chemistry

1 answer:

Marizza181 [45]3 years ago

6 0

Answer:

B. begin with a hypothesis

Explanation:

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Which of the following accurately pairs the part of an atom to its charge? A. Electron—no charge B. Proton—no charge C. Neutron—

Aneli [31]

Answer:

D: Electron - Negative Charge

Explanation:

Protons have a positive charge, (pro = +)

Neutrons have a negative charge, (neutral = 0

Electrons have a negative charge.

An element is determent by the number of protons in the atom, the Isotope of an element is determined by the number of neutrons, and the charge of an atom is determined by its electrons, which is equal to the number of protons.

7 0

3 years ago

I PLEASE HELP! How many liters of a 2.25 molar hydrobromic acid (HBr) solution would be needed to react completely with 100.0 gr

PtichkaEL [24]

Moles of calcium metal used = 100/40.1=2.5
Moles of HBr need to react = 5 moles
As the molar ratio is 1 is to 2 among them
so
Moles=molarity x volume
5=2.25 x volume
volume=2.22 litres of HBr required for this reaction
ANSWER IS 2.22 LITRES

8 0

2 years ago

What change in volume results if 60 mL of a gas is cooled from 33 C to 5 C?

Eva8 [605]

Answer:

Change in volume on changing temperature from 33 $^{\circ}C$ to 5 $^{\circ}C$ is 5.49 mL

Explanation:

Initial volume of gas = V = 60 mL

Assuming final volume of gas to be V' mL

Initial temperature = T = 33 $^{\circ}C$ = 306 K

Final temperature = T' = 5 $^{\circ}C$ = 278 K

The relationship between volume and temperature of gas at constant pressure is shown below

$\displaystyle \frac{V}{V'}=\displaystyle \frac{T}{T'} \\\displaystyle \frac{60\textrm{ mL}}{V'} = \displaystyle \frac{306\textrm{ K}}{T} \\V' = 54.51 \textrm{ mL} \\\textrm{Change in volume} = \left ( V-V' \right ) \\\textrm{Change in volume} = \left ( 60-54.51 \right )\textrm{ mL} \\\textrm{Change in volume} = 5.49 \textrm{ mL}$

Change in volume on changing temperature = 5.49 mL

6 0

3 years ago

An experiment requires 40.0g of ethylene glycol, a liquid whose density is 1.114 g/mL. Rather than weigh the sample on a balance

uranmaximum [27]

Density= mass/volume
volume=mass/density
volume= 40.0g/1.114g per mL
volume= 35.90664273 mL
volume = 35.9 mL

6 0

3 years ago

A scuba diver knows that she needs 50.0mol of air for an upcoming dive. What size (volume) tank will she need to fill for this d

erica [24]

Answer:

1120 L.

Explanation:

Hello!

In this case, as no conditions of pressure of temperature are given for this problem, we can assume that the scuba diver dives at STP (1 atm and 273.15 K), which means that 1 mole of air would occupy a volume of 22.4 L.

In such a way, since she needs 50.0 moles of air, the following ratio is useful to compute the size (volume) of the tank she needs:

$V_2=\frac{V_1*n_2}{n_1}$

Thereby, we plug in to obtain:

$V_2=\frac{22.4L*50.0mol}{1mol}\\\\V_2=1120 L$

Best regards!

4 0

3 years ago