The standard heat of formation is the heat released or absorbed when you obtain the CrO₃ compound. So, the reaction basically involves the individual elements of the compound. The complete balanced chemical reaction for the formation of CrO₃ is:

<em>2 Cr + 3 O₂ → 2 CrO₃</em>

6 0

3 years ago

Answer the questions about the characteristics of the elements in group 1 (the alkali metals). What happens when the elements in

irinina [24]

Answer:

See explanation

Explanation:

The elements in group form univalent positive ions and element in group 17 form univalent negative ions. Hence, when a group 1 element reacts with a group 17 element, a compound of the sort MX is formed. Hence, when a group 1 element reacts with bromine, a salt is formed with the general formula MBr.

Elements of group 1 are highly electro positive metals. They react with water to form the metal hydroxide and release hydrogen gas. Hence, when group 1 elements react with water, hydrogen gas is released.

A group 1 element forms a univalent positive ion while a group 16 element forms a divalent negative ion. Hence, when a groups 1 element reacts with oxygen, the compound formed must have the general formula M2O.

The reactivity of group 1 metal increases down the group hence Cs is the most reactive group 1 element.

Lithium displays a slightly different chemistry from other group 1 elements because of its small size.

6 0

3 years ago

why polychromatic light gives continious spectrum if passes throught prism and why polychromatic light gives line spectrum when

alukav5142 [94]

Answer:

I don’t know

Explanation:

4 0

3 years ago

) A technique once used by geologists to measure the density of a mineral is to mix two dense liquids in such proportions that t

sergeinik [125]

Hey there!

It is evident that the problem gives the mass of the bottle with the calcite, with water and empty, which will allow us to calculate the masses of both calcite and water. Moreover, with the given density of water, it will be possible to calculate its volume, which turns out equal to that of the calcite.

In this case, it turns out possible to solve this problem by firstly calculating the mass of calcite present into the bottle, by using its mass when empty and the mass when having the calcite:

$m_{calcite}=15.4448g-12.4631g=2.9817g$

Now, we calculate the volume of the calcite, which is the same to that had by water when weights 13.5441 g by using its density:

$V_{calcite}=V_{water}=\frac{13.5441g-12.4631g}{0.997g/mL}=1.084mL$

Thus, the density of the calcite sample will be:

$\rho _{calcite}=\frac{m_{calcite}}{V_{calcite}}\\\\\rho _{calcite}=\frac{2.9817g}{1.084mL}=2.750g/mL$

This result makes sense, as it sinks in chloroform but floats on bromoform as described on the last part of the problem, because this density is between 1.444 and 2.89. g/mL

Learn more:

Regards!

6 0

2 years ago