of the above 33 Which of the following produees the characteristie color of a B)

Question

of the above 33 Which of the following produees the characteristie color of a B) molecules energy levels c) electrons dropping to lower D) meelel dropping to lower eneruy levels none of the above 34) How many atoms of cobalt equal a mass of sa 93 g7 (Refer to the E) 6.02 1023 as What is the number of magnesium atoms that equal a mass of g? 24.31 B) 12 D) 6.02 E) none of the above 36) Which of the following is equal to 1.00 mole of substance? AJ 6.02 x 1023 um atoms, Na B) 6.02 x 1023 iodine molecules, 12 c) 6.02 x 1023 sodium iodide formula units, Nal D) all of the above E) none of the above

Explanation / Answer

Answer 34:

given mass = 58.93g

molecular weight of cobalt = 58.93 g/mol

moles of cobalt = 58.93/58.93 = 1 mole

1 mole contains = 6.022*1023 atoms

Hence, the number of cobalt atoms in 58.93g = 6.022*1023 atoms
Answer is E= 6.02*1023

Answer 35:

given mass = 24.31 g

molecular weight of Magnesium = 24.31g/mol

hence, moles of magnesium given = 24.31/24.31 = 1 mole

Hence, number of magnesium atoms will be = 6.022*1023 atoms, as 1 mole contains these many atoms.

Answer will be: D = 6.02*1023

Answer 36:

1 mole of any substance contains = 6.022*1023 atoms. Hence answer will be D-all of the above

Answer 37:

1 mole contains = 6.022*1023 krypton atoms. Hence, 2.5 moles will contain

= 2.5*6.022*1023

= 15.055*1023

= 1.5055*1024 Kr atoms

Hence answer is option C: 1.51*1024 atoms

Answer 38:

atomic weights of

oxygen (O) = 16 g/mol

hydrogen (H) = 1 g/mol

Carbon (C) = 12 g/mol

molecular weight of C9H8O4 = (12*9) + (8*1) + (16*4) = 180 g/mol

Hence, answer is C:180.17 g/mol

Answer 39:

atomic masses of:

carbon (C) = 12 g/mol

Nitrogen (N) = 14 g/mol

oxygen (O) = 16 g/mol

hydrogen (H) = 1 g/mol

given compound = C7H5(NO2)3

molecular weight will be = (7*12) + (5*1) + (14*3) + (16*6)

= 227 g/mol

Answer will be: D = 227.15 g/mol

Answer 40:

given mass = 3.2 g

molecular mass of CH4 = (12*1)+(4*1) = 16 g/mol

moles of methane given = 3.2/16 = 0.2 moles

1 mole = 6.022*1023 molecules of methane

hence, 0.2 moles = 0.2*6.022*1023

= 1.2044*1023 molecules

Hence, answer is option A = 1.2*1023 molecules

Answer 41:

1 mole of every gas occupies 22.4L volume at STP. Hence, answer will be D=all of the above

Answer 42:

1 mole of any substance occupies 22.4 L volume at STP and 6.022*1023 molecules/atoms.

Hence answer will be D = 6.02*1023

Answer 43:

from ideal gas law, PV = nRT

P = pressure in atm

V = volume in L

n = number of moles

R = gas constant = 0.082 Latm/molK

T = temperature in Kelvin

At STP

P = 1 atm and T = 273.15 K

n = PV/RT

= 1*5/(0.082*273.15)

= 0.223 moles

mass in 0.223 moles of oxygen gas = 0.223*32 = 7.14g

32 is the molecular weight of oxygen gas (O2)

Answer: 44

from ideal gas law:

PV = nRT

density, d = mass/volume and moles = mass/molecular weight (i.e m/MW)

PV = (m/MW)*RT

P*MW = (m/V)*RT

P*MW = dRT

d = P*MW/RT

P = 1 atm and T = 273.15 K at STP

MW = 28 g/mol for nitrogen gas

substituting values, we get

d = (1*28)/(8.314*273.15) = 0.0125 kg/m3 = 1.25 g/L

Answer is C = 1.25 g/L

Answer 45:

moles of nitrogen gas given = 0.75/28 = 0.02678 moles

from ideal gas law

PV = nRT

P = 1 atm . T = 273.15 K R = 0.082 Latm/molK and n = 0.02678 moles

substituting, we get V = 0.6 L

answer is A = 0.6 L

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