Answer:
B) 4 hours
Explanation:
the equation relating speed , distance and time is as follows
speed = distance / time taken
the van moves 50 miles at 20 mph and the next 84 miles at 56 mph
so lets calculate the time taken at both speeds
substituting the values in the above equation
20 mph = 50 miles / time
time taken = 50 / 20 = 2.5 hours
56 mph = 84 miles / time
time taken = 1.5 hours
the totat time taken is - 2.5 + 1.5 = 4 hours
Answer:
If the mass of carbon in the signature is 10-12g, calculate. the number of carbon atoms in the signature. the answer is 5.01 x 10^10 atom.
Explanation:
wlcm
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The answer would be bromine because electronegativity increases as you move up and to the right on the periodic table, and if you keep moving right you will see that bromine has the highest electronegativity out of those four elements.
Answer:
pH = 11.9
Explanation:
First, we <u>determine the number of OH⁻ moles dissolved</u>:
<em>80% of Ca(OH)₂ is dissolved</em>:
- 0.0005 mol * 80/100 = 4x10⁻⁴ mol Ca(OH)₂
<em>There are two OH⁻ moles per Ca(OH)₂ mol</em>:
- 4x10⁻⁴ * 2 = 8x10⁻⁴ mol OH⁻
Now we can <u>calculate the molar concentration of OH⁻</u> (moles/L):
- 100 mL ⇒ 100/1000 = 0.1 L
- [OH⁻] = 8x10⁻⁴ mol / 0.1 L = 8x10⁻³ M
Then we <u>calculate the pOH of the solution</u>:
- pOH = -log[OH⁻] = -log(8x10⁻³ M) = 2.10
Finally, we can <u>calculate the pH of the solution</u> using the equation