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IrinaVladis [17]
3 years ago
8

Which element is located in period 4?

Chemistry
1 answer:
Lena [83]3 years ago
6 0

Answer:

i beleive iron

Explanation:

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A cube of butter weighs .254 pounds and has a volume of 129.4 milliliters what is the density
ira [324]
Density = Mass/Volume

d = .254/129.4
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3 years ago
Which best explains why a bacterial cell is classified as a prokaryote?
8090 [49]


b the absence of a nucleus


6 0
3 years ago
28. How many formula units are found in 0.250 moles of potassium nitrate?
Soloha48 [4]

Answer:

\boxed {\boxed {\sf B. \ 1.5 *10^{23} \ formula \ units}}

Explanation:

1 mole of any substance contains the same number of particles. The particles can vary (atoms, molecules, formula units), but there are always 6.022*10²³ particles. In this case, the particles are formula units of potassium nitrate or KNO₃.

Let's create a ratio.

\frac {6.022*10^{23} \ formula \ units  \ KNO_3}{1 \ mol \ KNO_3}

Since we are trying to find the formula units in 0.250 moles, we multiply by that number.

0.250 \ mol \ KNO_3 *\frac {6.022*10^{23} \ formula \ units  \ KNO_3}{1 \ mol \ KNO_3}

The units of moles of potassium nitrate cancel.

0.250  *\frac {6.022*10^{23} \ formula \ units  \ KNO_3}{1 }

The denominator of 1 can be ignored, so we can make a simple multiplication problem.

0.250  *{6.022*10^{23} \ formula \ units  \ KNO_3}

1.5055 * 10^{23} \ formula \ units \ KNO_3

If we round to the nearest tenth, the 0 in the hundredth place tells us to leave the 5 in the tenth place.

1.5 *10^{23} \ formula \ units \ KNO_3

0.250 moles of potassium nitrate is approximately equal to 1.5*10²³ formula units of potassium nitrate and choice B is correct.

7 0
3 years ago
You see a worm crawling along the ground and wonder if scientists consider it living or nonliving. Which item below would not be
lisov135 [29]

Answer: a. A worm can move so it must be living.

Explanation:

If a worm is moving it is classified as a moving worm also known to be living if moving.

A worm could reproduce therefore it is living.

Worms do pass dirt into and through there bodies to eat of the minerals and discarding things through and let out.

If you do cut a worm in half it may damage it but since it has basically two heads on girl one boy and cut in half it may split them up, and make damage but they will eventually grow back if the injuries are not severe.

        I Gave Some Facts and I Hope This Will Help!

HAPPY NEW YEAR!

4 0
3 years ago
Using the model of the periodic table, which two elements pictured have similar chemical properties?
Murljashka [212]

Answer:

1 and 3

Explanation:

The vertical columns (groups) of the periodic table are arranged such that all its elements have the same number of valence electrons. All elements within a certain group thus share similar properties.

5 0
3 years ago
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