Which statement best characterizes chemical reactions

There are seven types of crystals. Which of these is not one of the seven?

Gelneren [198K]

The answer is B. tetraclinic

3 0

3 years ago

Read 2 more answers

What is atomic hydrogen?<br>

goldenfox [79]

A hydrogen atom is an atom of the chemical element hydrogen. The electrically neutral atom contains a single positively charged proton and a single negatively charged electron bound to the nucleus by the Coulomb force. Atomic hydrogen constitutes about 75% of the baryonic mass of the universe.

8 0

3 years ago

Read 2 more answers

A 0.1326 g sample of magnesium was burned in an oxygen bomb calorimeter. the total heat capacity of the calorimeter plus water w

Sladkaya [172]

Answer: Th enthalpy of combustion for the given reaction is 594.244 kJ/mol

Explanation: Enthalpy of combustion is defined as the decomposition of a substance in the presence of oxygen gas.

W are given a chemical reaction:

$Mg(s)+\frac{1}{2}O_2(g)\rightarrow MgO(s)$

$c=5760J/^oC$

$\Delta T=0.570^oC$

To calculate the enthalpy change, we use the formula:

$\Delta H=c\Delta T\\\\\Delta H=5760J/^oC\times 0.570^oC=3283.2J$

This is the amount of energy released when 0.1326 grams of sample was burned.

So, energy released when 1 gram of sample was burned is = $\frac{3283.2J}{0.1326g}=24760.181J/g$

Energy 1 mole of magnesium is being combusted, so to calculate the energy released when 1 mole of magnesium ( that is 24 g/mol of magnesium) is being combusted will be:

$\Delta H=24760.181J/g\times 24g/mol\\\\\Delta H=594244.3J/mol\\\\\Delta H=594.244kJ/mol$

4 0

3 years ago

What is the name of the process that plants use to remove carbon from the atmosphere

Studentka2010 [4]

Photosynthesis is the process by which plants take in carbon and use it for energy and produce oxygen.

8 0

3 years ago

Label each of the following changes as a physical change or chemical change. Give evidence to support your answer.

SVEN [57.7K]

Answer:

A catalytic converter changes nitrogen dioxide to nitrogen gas and oxygen gas is a chemical change.

Explanation:

Hello.

In this case, since physical changes do not modify the molecular composition and structure of the material undergoing it whereas the chemical change does, for catalytic converters we should know they promote chemical reaction in which the composition is changed; for instance, for the given example, the following chemical reaction is the evidence:

$2NO_2\rightarrow N_2+O_2$

As you can see, nitrogen and oxygen are no longer bonded but separated by themselves, therefore, this is a chemical change.

Best regards.

3 0

3 years ago