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Alexxx [7]
3 years ago
8

The scientific theory of _________ states that populations change over time in response to changes in the environment.

Chemistry
1 answer:
Leto [7]3 years ago
5 0
Natural selection I think
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The decomposition of NI3 to form N2 and I2 releases −290.0 kJ of energy. The reaction can be represented as 2NI3(s)→N2(g)+3I2(g)
EastWind [94]

Answer:

-7.34 kilo Joules is the change in enthaply when 20.0 grams of nitrogen triiodide decomposes.

Explanation:

Mass of nitrogen triiodide = 20.0 g

Moles of nitrogen triiodide = \frac{20.0 g}{395 g/mol}=0.05063 mol

2NI_3(s)\rightarrow N_2(g)+3I_2(g), \Delta H_{rxn}=-290.0 kJ

According to reaction, 2 moles of nitrogen triiodide gives 290.0 kilo Joules of heat on decomposition ,then 0.05063 moles of nitrogen triiodide will give :

\frac{-290.0 kJ}{2}\times 0.05063=-7.34 kJ

-7.34 kilo Joules is the change in enthaply when 20.0 grams of nitrogen triiodide decomposes.

3 0
3 years ago
True or false? the iron recommendation for girls exceeds that of boys during adolescence.
sashaice [31]

It is true that the iron recommendation for girls exceeds that of boys during adolescence.

During an adolescence, girls and boys require iron for a large growth spurt and the gain of adult phenotypes and biologic rhythms.

In this period of the life, iron recommendation increase in both girls and boys, because of the increase in lean body mass, the expansion of the total blood volume, the increase and start of menstruation at girls.

Iron is essential for oxygen transport, red blood cell creation, cognitive performance and immunological function.

The overall iron requirements for girls are up to twice as boys.

More about adolescence: brainly.com/question/13528489

#SPJ4

4 0
1 year ago
A. Clearly draw the Lewis structure for the PBr4- ion. Show your math where
Nataliya [291]

Answer:

   Br

    |

Br-P-Br

    |

   Br

Explanation:

To calculate the valance electrons, look at the periodic table to find the valance electrons for each atom and add them together. P is in column 5A, so it has 5, Br is in column 7A, so it has 7 (multiply by 4 since there are 4 Br atoms to give 28) and there is a 1- charge, so add one more electron. 5+28+1=34, so there are 34 electrons to place. P would be the central atom, so place it in the middle. Place each Br around the P (as shown above) with a a single line connecting it. Each line represents 2 electrons, so 8 total have been place, leaving 26 remaining. Place 6 electrons around each Br (2 on each of the unbonded sides), which leaves 2 electrons remaining. The remaining pair of unbound electrons will be attached to the P between any two Br atoms. Phosphorus doesn't have to follow the octet rule, so it actually ends up with 10 valance electrons.

4 0
3 years ago
Read 2 more answers
Which of the following structures are accessory structures of the digestive system?
professor190 [17]

the pancreas and the liver

7 0
3 years ago
Read 2 more answers
A vial containing radioactive selenium-75 has an activity of 3.0 mCi/mL. If 2.6 mCi are required for a leukemia test, how many m
oksian1 [2.3K]

Answer : The 866.66\mu L must be administered.

Solution :

As we are given that a vial containing radioactive selenium-75 has an activity of 3.0mCi/mL.

As, 3.0 mCi radioactive selenium-75 present in 1 ml

So, 2.6 mCi radioactive selenium-75 present in \frac{2.6mCi}{3.0mCi}\times 1ml=0.86666ml\times 1000=866.66\mu L

Conversion :

(1ml=1000\mu L)

Therefore, the 866.66\mu L must be administered.

4 0
3 years ago
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