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2 years ago

Round off 318.90 to 2 significant figures

Chemistry

1 answer:

motikmotik2 years ago

6 0

Answer:

320

Explanation:

Because the question is asking for 2 significant figures, you want to try to get rid of all of the numbers to the right of the 1. That way, the only numbers that will be significant are the numbers in the position of the 3 and the 1.

Before you can make the rest of the numbers equal 0, you need to correctly round the number in the last significant position (the number 1).

If the number to the right of the 1 is from 0-4, the number stays the same. If the number is from 5-9, the 1 needs to be increased by a unit.

Since the number to the right is an 8, you need to change the 1 to a 2. Now, you can make all of the other numbers a 0. There should be no decimal place because it would mean that the zero to the left of it is significant.

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When 35.0 mL of 0.400 M hydrobromic acid and 35.0 mL of 0.400 M ammonia are combined, the pH of the resulting solution will be :

Kay [80]

Answer:

B. Equal to 7.

Explanation:

Hydrobromic acid is a strong acid that decreases pH and ammonia is a strong base that increases pH.

As the initial pH of water is 7,0 the addition of 35.0mL of 0.400M HBr will produce a pH less than 7,0. But, the same effect of decreasing pH is reverted for the addition of 35.0mL of 0.400M HNO3.

That means the net effect of the two addition is to have a pH:

B. Equal to 7.

I hope it helps!

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3 years ago

The Hawaiian islands formed as a result of a hot spot. A.)True B.)False

choli [55]

Hello,

That is true.

8 0

3 years ago

Read 2 more answers

A sample of gas with an initial volume of 28.4 Liters at a pressure of 725 mmHg and a temperature of 305 K is compressed to a vo

Lerok [7]

Answer:

The final pressure is 2.25 atm or 1710 mm Hg

Explanation:

Step 1: Data given

The initial volume = 28.4 L

The initial pressure = 725 mm Hg ( = 725/760 atm) = 0.953947 atm

The initial temperature = 305 K

The new volume is 14.8 L

The new temperature = 375 K

Step 2: Calculate the new pressure

(P1*V1)/T1 = (P2*V2)/T2

⇒ with P1 = the initial pressure = 725 mmHg = 0.953947 atm

⇒ with V1 = the initial volume = 28.4 L

⇒ with T1 = The initial temperature = 305 K

⇒ with P2 = the new pressure = TO BE DETERMINED

⇒ with V2 = the new volume = 14.8 L

⇒ with T2 = the new temperature = 375 K

(0.953947 * 28.4)/305 = (P2 * 14.8)/375

P2 = 2.25 atm = 1710 mm Hg

The final pressure is 2.25 atm or 1710 mm Hg

6 0

3 years ago

Match the set of measurements of the boiling point of water with the best

Mashcka [7]

Answer:

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Explanation:

6 0

3 years ago

A solution is prepared by adding 0.0231moles of H3O+ ions to 3.33L of water. What is the pH of this solution

MrMuchimi

Answer:

2.15

Explanation:

For this question, we have to remember the pH formula:

$pH~=~-Log[H_3O^+]$

By definition, the pH value is calculated when we do the -Log of the concentration of the hydronium ions ( $H_3O^+$ ). So, the next step is the calculation of the concentration of the hydronium ions. For this, we have to use the molarity formula:

$M=\frac{mol}{L}$

We already know the number of moles (0.0231 moles) and the volume (3.33 L). So, we can plug the values into the molarity formula:

$M=\frac{0.0231~moles}{3.33~L}=0.00693~M$

With this value, now we can calculate the pH value:

$pH~=~-Log[0.00693~M]~=~2.15$

The pH would be 2.15

I hope it helps!

8 0

3 years ago