Which of the following does not have a uniform composition throughout? A) Compound B) Homogeneous mixture C) Heterogeneous mixture D) Solvent E) Element The mass of a sample is 550 milligrams. Which of the following expresses that mass in kilograms? A) 5.5 times 10^5 kg B) 5.5 times 10^-4 kg C) 5.5 times 10^-1 kg D) 5.5 times 10^8 E) 5.5 times 10^-6 kg What is the volume of a container that contains 14.3 g of a substance having a density of 0.988 g/cm^3? A) 691 cm^3 B) 14.1 cm^3 C) 14.5 cm^3 D) 141 cm^3 E) 0.0691 cm^3 How many neutrons are there in an atom of lead whose mass number is 208? A) 126 B) 82 C) 290 D) 208 E) none of them

Question

Chemistry

Ashtyn Andersen

4 April, 15:57

Which of the following does not have a uniform composition throughout? A) Compound B) Homogeneous mixture C) Heterogeneous mixture D) Solvent E) Element The mass of a sample is 550 milligrams. Which of the following expresses that mass in kilograms? A) 5.5 times 10^5 kg B) 5.5 times 10^-4 kg C) 5.5 times 10^-1 kg D) 5.5 times 10^8 E) 5.5 times 10^-6 kg What is the volume of a container that contains 14.3 g of a substance having a density of 0.988 g/cm^3? A) 691 cm^3 B) 14.1 cm^3 C) 14.5 cm^3 D) 141 cm^3 E) 0.0691 cm^3 How many neutrons are there in an atom of lead whose mass number is 208? A) 126 B) 82 C) 290 D) 208 E) none of them

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Jorge Dodson · Answer 1

Heterogeneous mixture = C

1 gram = 1000 milligram

1000gram = 1kg

1000x1000 milligram = 1kg

1,000,000milligram = 1kg

550milligram = 550/1,000,000 = 5.5 x 10 ^ - 4

5.5 times 10^-4 kg = B

Density = Mass / Volume

Volume = mass / density = 14.3/0.988 = 14.47cm^3

Lead has 82 protons,

An atom comprises of proton and neutrons.

the number of neutrons in an atom of lead given as 208 will then

Atom = proton + neutron

208 = 82 + neutron

208 - 82 = 126 neutrons