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Studentka2010 [4]

3 years ago

14

A chemical reaction takes place in a closed system. The mass of the reactants before the reaction was grams. What must the mass

of the products of the reaction be, according to the law of conservation of mass?
A. 35 grams B. 30 grams C. 70 grams D. 25 grams

1 answer:

Ad libitum [116K]3 years ago

7 0

Answer:

D. 25 grams

Explanation:

I think that's what the answer is

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Below are the steps of the engineering process (not necessarily in order): 1) Know the background 2) Do the work 3) Make a plan

LuckyWell [14K]

Answer:

4 - 1 - 3 - 2 - 6 - 5

Explanation:

During an engineering process, first, we need to identify the problem, or the need because the process only will occur because of some need. Then, it's necessary to know as much as possible about the problem and the things that already exist or already were tested to solve it. Knowing the background will make the work easy.

After that, it's necessary to plan the things we'll do, knowing the costs, the time needed for activities, how many people will be necessary for each step, etc. It's really important to make a plan. Then, do the work, following the plan. Thus, the process must be tested. During the test of the results, some problems must be found, so it's time to evaluate and redesign the process, to solve these problems found.

3 0

3 years ago

What is 30-9x2*2-21-4+4

IgorC [24]

Answer:
9 (1-2x²)

Explanation:
The given expression is:
30 - 9x²*2 - 21 - 4 + 4
The first step is to compute the multiplication. This will give:
30 - 18x² - 21 - 4 + 4
Then, we will add like terms as follows:
(30-21-4+4) - 18x²
= 9 - 18x²
Finally, we can take the 9 as a common factor from both terms, this will give:
9 (1-2x²)

Hope this helps :)

5 0

3 years ago

Glucose, C6H12O6,C6H12O6, is used as an energy source by the human body. The overall reaction in the body is described by the eq

Ilia_Sergeevich [38]

Answer:

Mass of oxygen = 61.824 g

Mass of carbon dioxide = 85.01 g

Explanation:

Given data:

Mass of glucose = 58 g

Mass of carbon dioxide = ?

Mass of oxygen = ?

Solution:

First of all we will write the balanced chemical equation,

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

Moles of glucose:

Number of moles = mass / molar mass

Number of moles = 58 g/180 g/mol

Number of moles = 0.322 mol

Now we compare the moles of oxygen with glucose from balance chemical equation.

C₆H₁₂O₆ : O₂

1 : 6

0.322 : 0.322×6 = 1.932 mol

Mass of oxygen:

Mass of oxygen = number of moles × molar mass

Mass of oxygen = 1.932 mol × 32 g/mol

Mass of oxygen = 61.824 g

Now we compare the moles of carbon dioxide with moles of glucose and oxygen.

C₆H₁₂O₆ : CO₂

1 : 6

0.322 : 0.322×6 = 1.932 mol

O₂ : CO₂

6 : 6

1.932 : 1.932

Mass of carbon dioxide;

mass of carbon dioxide = number of moles × molar mass

mass of carbon dioxide = 1.932 mol × 44 g/mol

mass of carbon dioxide = 85.01 g

7 0

3 years ago

4 Na + O2 → 2 Na2O<br><br> 6.79 moles of O2 will react to form how many moles of Na2O?

Nataly_w [17]

Answer:

13.94moles of Na₂O

Explanation:

The balanced reaction expression is given as:

4Na + O₂ → 2Na₂O

Given parameters:

Number of moles of O₂ = 6.97moles

Unknown:

Number of moles of Na₂O

Solution:

To solve this problem;

1 mole of O₂ will produce 2 moles of Na₂O ;

6.97 moles of O₂ will produce 6.97 x 2 = 13.94moles of Na₂O

6 0

2 years ago

Why the is ratio of magnesium ions to chloride ions in MgCl2 is 1:2?

Monica [59]

You should read up on Proust's law, better known as the Law of Definite Proportions. This is a chemical law that defines your question more generally, on why the ratio of elements and ions are always fixed.

Basically, this compound Magnesium(II) Chloride is MgCl2 because it has the same number of protons, neutrons, and electrons all the way. This defines the properties of the compound or atom.

5 0

3 years ago