Elements A and Q form two compounds, AQ and A 2 Q 3 . The mass ratio (mass Q)/(m

Question

Elements A and Q form two compounds, AQ and A2Q3. The mass ratio (mass Q)/(mass A) for AQ is 0.574. What is the mass ratio (mass Q)/(mass A) for A2Q3?

Select one:

A. 1.16

B. 0.383

C. 0.861

D. 2.61

A baseball with a mass of 150 g is moving at a velocity of 40 m/s (90 mph). If the uncertainity in the velocity is 0.1 m/s, the uncertainty in position

Select one:

A. must be greater than or equal to 4 × 10-33 m.

B. must be less than or equal to 4 × 10-33 m.

C. must be 4 × 10-33 m.

D. may be zero.

The work function of copper metal is 437 kJ/mol. What is the maximum wavelength of light that can be used to eject electrons from copper?

Select one:

A. 2.74 × 10-7m

B. 6.36 × 10-7m

C. 2.65 × 10-7m

D. 5.42 × 10-7m

Which of the compounds, Li3P, PH3, C2H6, IBr3, are ionic compounds?

Select one:

A. only C2H6

B. only Li3P

C. PH3, C2H6, and IBr3

D. Li3P and PH3

Explanation / Answer

mQ/mA = 0.574
mQ = 0.574*mA

In A2Q3:
Mass of A = 2*mA
Mass of Q = 3*mQ
mass of Q/ mass of A = 3*mQ/2*mA = (3/2)*(mQ/mA) = (3/2)*0.574 = 0.861
Answer: C

use:
delta x * M* delta V >=h/2pi
delta x * 0.15* 0.1>= (6.626*10^-34)/2pi
delta x >= 7*10^-33
Answer: B. must be less than or equal to 4 × 10-33 m.

1 mol = 437000 J
1 atom = (437000)/(6.022*10^23) =
use:
E = h*c/lambda
7.3*10^-19= (6.626*10^-34)*(3*10^8 ) / lambda
lambda = 2.74*10^-7 m
Answer: A

Answer:B. only Li3P

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