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3 years ago

Describe how you could feel weightless on Earth.

1 answer:

5 0

Gravity is a force that acts between the Earth's mass and the mass of other objects that surround it. ... Astronauts merely feel weightless because there is no external contact force pushing or pulling upon their body. They are in a state of free fall.

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Draw the lewis dot structures for each of the following molecules. show the resonance structures, if they exist

jonny [76]

What dont u understand about lewis dot structures???.
.how to determine the number of dots ..or

5 0

3 years ago

If 2.68 g of benzaldehyde are involved with the mixed aldol condensation reaction, how many moles of benzaldehyde are present? R

Zielflug [23.3K]

Answer:

The number of moles of benzaldehyde = 0.0253 moles

Explanation:

The molecular formula of benzaldehyde is C₇H₆O

Its molecular mass is calculated from the atomic masses of the constituent atoms.

C = 12.0 g: H = 1.0 g; O = 16.0 g

Molecular mass = ( 12 * 7) + (1 * 6) + (16 * 1) = 106.0 g/mol

Number of moles of substance = mass of substance/ molar mass of the substance

mass of benzaldehyde = 2.68; molar mass = 106.0 g/mol

Number of moles of benzaldehyde = 2.68 g/ 106 g/mol = 0.0253 moles

Therefore, the number of moles of benzaldehyde = 0.0253 moles

8 0

3 years ago

Distinguish between accuracy and precision in measurements

nignag [31]

The accuracy is associated with magnitude of fractional error or relative error in that measurement

the precision of a measurement is associated with least count of the measuring instrument.

precision does not mean accuracy but both are highly demanded while making measurements in physics.

7 0

3 years ago

in an experiment 3.425g of lead oxide was reduced to form 3.105g of lead the empirical formula of the lead oxide is?

Romashka-Z-Leto [24]

Answer:

Pb3O4

Explanation:

According to this question, 3.425g of lead oxide was reduced to form 3.105g of lead in an experiment. Since lead oxide contains both lead (Pb) and oxygen (O) element,

Mass of lead oxide = 3.425g

Mass of lead = 3.105g

Mass of oxygen = (3.425g - 3.105g) = 0.320g

Next, we convert each mass value to mole by dividing by respective molar mass

Pb = 3.105g ÷ 207.2 = 0.0149mol

O = 0.320g ÷ 16 = 0.02mol

Next, we divide each mole value by the smallest (0.0149)

Pb = 0.0149mol ÷ 0.0149mol = 1

O = 0.02mol ÷ 0.0149mol = 1.342

Multiply each ratio value by 3 to get:

Pb = 1 × 3 = 3

O = 1.342 × 3 = 4.026

The whole number ratio, approximately, of Pb and O is 3:4, hence, their empirical formula is Pb3O4.

4 0

3 years ago

Which type of relationship exists between Alaskan brown bears and salmon? A. predation B. mutualism C. competition D. commensali

aksik [14]

Answer:

A. predation.

Explanation:

Predation is a type of ecological interaction in which one organism which is known as predator feeds upon another organism thereby killing it. The organism which is killed by predator is known as prey. In such interaction one organism is benefited while another one is harmed.

Brown bears of Alaska feed upon salmon. In order to so they have developed many ways which include waiting at the bottom of falls from where salmons pass by or standing at the bottom of the falls.

3 0

3 years ago