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Sever21 [200]
3 years ago
10

If a sample of pure sodium has a mass of 8.2 grams and sodium has an average atomic mass of 22.99 g/mol, how many sodium atoms a

re there in the sample?
3.21 x 1021 atoms
2.15 x 1023 atoms
1.69 x 1024 atoms
1.13 x 1026 atoms
Mathematics
1 answer:
Nonamiya [84]3 years ago
7 0
8.2 grams = 1 mol
Na ________
22.99 grams

First multiply the value of 8.2 to 1. Then divide by the value of 22.99 to determine the number of moles of sodium present in the 8.2 gram sample.

Then use the following equation to solve for sodium atoms.

Number of moles of Na • Avogadro Number = Number of sodium atoms.

0.3566782 • (6.02 X 10^23). = 2.1472 X 10 ^ 23. Or 2.15 X 10 ^ 23.

The answer is the second option - 2.15 X 10 ^ 23.
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I need to know the surface area.
egoroff_w [7]
Id say it 93.57 i believe

8 0
3 years ago
1. (You may get teacher help with this during tutoring)
Nezavi [6.7K]

Answer:

1A --- 25

1B --- (5 + 4) x 2 + 6 - 2 x 2 - 1 = 19

2A --- -206

2B --- ?

3A --- 5.8 × 10⁷

3B --- 2.5 × 10⁻³

4A --- 4.67 × 10¹³

4B --- 3.5 × 10⁻³

5A --- 9 × 10⁶

5B --- 1.68 × 10¹⁰

5C --- All ants combined weigh 112.46 times more than all humans combined

Step-by-step explanation:

(I am using PEMDAS for Order of Operations)

1A -----------------------------------------------

6 × 7 - 3² × 9 + 4³

<u>Parenthesis</u>

No parenthesis.

<u>Exponents</u>

6 × 7 - 3² × 9 + 4³

6 × 7 - 9 × 9 + 64

<u>Multiplication</u>

6 × 7 - 9 × 9 + 64

42 - 81 + 64

<u>Division</u>

No division.

<u>Addition</u>

42 - 81 + 64 (the 81 is negative)

42 + -17

25

1B --------------------------------------

5 + 4 x 2 + 6 - 2 x 2 - 1 = 14

(5 + 4) x 2 + 6 - 2 x 2 - 1 = 19

9 x 2 + 6 - 2 x 2 - 1

18 + 6 - 2 x 2 - 1

18 + 6 - 4 - 1

24 - 5

19

2A --------------------------------------------

3 × 7 - 3³ × 9 + 4²

<u>Parenthesis</u>

No parenthesis

<u>Exponents</u>

3 × 7 - 27 × 9 + 16

<u>Multiplication</u>

21 - 27 × 9 + 16

21 - 243 + 16

<u>Addition</u>

21 - 243 + 16

21 - 227

<u>Subtraction</u>

21 - 227

-206

2B ---------------------------------------------

5 + 3 × 2 + 6 - 2 × 3 - 7 = 4

(sorry cant figure this one out)

3A ------------------------------------------------

Move the decimal point in 58,000,000.0 over x times until you have 5.8000000. It was moved to the left 7 times, so the answer is 5.8 × 10⁷.

3B -----------------------------------------------

Move the decimal point in 0.0025 over x times until you have 2.5. It was moved to the right 3 times, so the answer is 2.5 × 10⁻³.

4A -----------------------------------------------

Move the decimal point in 46,700,000,000,000.0 x times until you have 4.67. It was moved to the left 13 times so the answer is 4.67 × 10¹³.

4B ----------------------------------------------

Move the decimal point in 0.0035 x times until you have 3.5. It was moved to the right 3 times, so the answer is 3.5 × 10⁻³.

5A -------------------------------------------------

(4.5 × 10³)(2 × 10³)

4.5 × 2 = 9

10³ × 10³ = 10⁶

9 × 10⁶

5B ------------------------------------------------------

(1.4 × 10⁵)(1.2 × 10⁵)

1.4 × 1.2 = 1.68

10⁵ * 10⁵ = 10¹⁰

1.68 × 10¹⁰

5C ---------------------------------------------------------

An adult human is 65 kilograms.

6.5 × 10¹ grams

An ant is (you didnt say how many so im going with) 5 grams.

5 × 10⁰ grams

6.84 billion humans

6,840,000,000.0 humans

6.84 × 10⁹ humans

10,000 trillion ants

1 × 10¹⁶ ants

Weight of humans:

(6.5 × 10¹)(6.84 × 10⁹)

44.46 × 10¹⁰

All humans weigh 4.446 × 10¹¹ kilograms

Weight of ants:

(5 × 10⁰)(1 × 10¹⁶)

All ants weigh 5 × 10¹⁶ grams

1000 grams per kilogram

1000 = 1 × 10³

5 × 10¹⁶ ÷ 1 × 10³

5 ÷ 1 = 5

16 - 3 = 13

All ants weigh 5 × 10¹³ kilograms

All humans weigh 4.446 × 10¹¹ kilograms

5 × 10¹³ ÷ 4.446 × 10¹¹ = 112.46

All ants combined weigh 112.46 times more than all humans combined


7 0
3 years ago
Please help me this will mark brainiest thx I will appreciate it thank you
Savatey [412]

Answer:

z=40 degrees

x=90 degrees

y=40 degrees

Step-by-step explanation:

To solve z you know that 50+90+z= 180 degrees. So z equals 40. To solve x you subtract 90 from 180 to get 90 degrees. To solve you add 50+x+y. You know that x= 90. You would add the angles together to get 180 degrees. 50+90=140 and 180-140 equals 40. Sorry if i'm wrong.

6 0
3 years ago
Are all congruent rectangles similar?
shusha [124]

All congruent rectangles similar because comparable shapes are not always congruent.

Given that,

We have to find are all congruent rectangles similar.

We know that,

Each side's length and the angles that separate them match those of the other shape's corresponding sides and angles. Comparable shapes are not always congruent, whereas congruent shapes are always similar.

So,

Similar figures are not always congruent, whereas congruent figures are always similar. For similar figures, we simply take into account the shapes, however for congruent triangles, we take into account both the shapes and sizes of the figure.

Therefore, All congruent rectangles similar because comparable shapes are not always congruent.

To learn more about congruent visit: brainly.com/question/26044249

#SPJ4

5 0
1 year ago
Angles C and E are complementary angles. Angle C measures (4× + 50). Angle E measures 28 degrees. Solve for x.​
julsineya [31]

Answer:

x = 3

Step-by-step explanation:

4x + 50 + 28 = 90

4x + 78 = 90

4x = 12

x = 3

7 0
3 years ago
Read 2 more answers
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