The solutions are the following :
12. C
13. A.
Topaz and quartz
Explanation:
Topaz and quartz are minerals that will scratch feldspars but will not scratch corundum. Corundum is one of the hardest substance based on moh's scale.
The hardness of a mineral is its resistance to deformation. A mineral is harder than another if it can scratch it.
The moh's scale of hardness list minerals in the order of their hardness:
- Talc
- Gypsum
- Calcite
- Fluorite
- Apatite
- Orthoclase
- Quartz
- Topaz
- Corundum
- Diamond
Diamond is the hardest and talc is the softest.
Orthoclase is a feldspar.
learn more:
Rocks as mineral aggregates brainly.com/question/6568161
Silicate minerals brainly.com/question/4772323
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I'm assuming that C is carbon.

55.1259 g of C
Answer:

Explanation:
The given equation for the chemical reaction can be expressed as;

Using Hess Law to determine how much heat is produced by the decomposition of exactly 1 mole of H2O2 under standard conditions; we have the expression showing the Hess Law as follows:

At standard conditions;
the molar enthalpies of the given equation are as follows:



Replacing them into above formula; we have:


The above is the amount of heat of formation for two moles of hydrogen peroxide; thus for 1 mole hydrogen peroxide ; we have :


Hence; the heat produced after the decomposition of 1 mole of hydrogen peroxide is -54.04 kJ/mol
Answer:
Hydrogen is an example of an element because its displayed on the periodic table of elements
Explanation: