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tangare [24]
3 years ago
13

A helium atom has 2 protons and 2 neutrons.what is the mass number of this atom?

Chemistry
1 answer:
Scrat [10]3 years ago
8 0
4. Just add the protons and neutrons together.
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How many grams of water are made from the reaction of 16.0 grams of o2? given the reaction: 2h2 o2 --> 2h2o
Jlenok [28]

Answer:

18.0 g H₂O

Explanation:

To find the mass of water (H₂O), you need to (1) convert grams O₂ to moles O₂ (via the molar mass), then (2) convert moles O₂ to moles H₂O (via mole-to-mole ratio from equation coefficients), and then (3) convert moles H₂O to grams H₂O (via the molar mass). It is important to arrange the conversions in a way that allows for the cancellation of units. The final answer should have 3 sig figs to match the sig figs of the given value.

Molar Mass (O₂): 2(15.998 g/mol)

Molar Mass (O₂): 31.996 g/mol

Molar Mass (H₂O): 2(1.008 g/mol) + 15.998 g/mol

Molar Mass (H₂O): 18.014 g/mol

2 H₂ + 1 O₂ -----> 2 H₂O

16.0 g O₂          1 mole            2 moles H₂O         18.014 g
---------------  x  ----------------  x  ---------------------  x  -----------------  = 18.0 g H₂O
                        31.996 g             1 mole O₂             1 mole

6 0
1 year ago
5 advantages of storing oil underground in salt dome?
jasenka [17]

Answer:

Salt domes storage has advantages in cost, security, environmental risk, and maintenance. Salt formations offer the lowest cost, most environmentally secure way to store crude oil for long periods of time. Stockpiling oil in artificially-created caverns deep within the rock-hard salt costs historically about $3.50 per barrel in capital costs. Storing oil in above ground tanks, by comparison, can cost $15 to $18 per barrel - or at least five times the expense. Also, because the salt caverns are 2,000-4,000 feet below the surface, geologic pressures will sea; any crack that develops in the salt formation, assuring that no crude oil leaks from the cavern. An added benefit is the natural temperature differential between the top of the caverns and the bottom - a distance of around 2,000 feet; the temperature differential keeps the crude oil continuously circulating in the caverns, giving the oil a consistent quality.

4 0
3 years ago
Which of the following best describes a mole as used in chemistry?
bazaltina [42]

Answer: a very large number of objects

Explanation: Mole is the amount of objects and it has the usually Avogadro number of atoms, molecules, ions, etc in chemistry

8 0
2 years ago
The is the si unit that expresses the amount of substance. Specifically, it is defined as the amount of substance containing the
Dmitry_Shevchenko [17]

The <u>Mole</u> is the SI unit that expresses the amount of substance.

Mole is defined as - The mole is the amount of substance containing the same number of entities as there are in the 12 grams of Carbon - 12.

Mole is denoted by using symbol mol.

      Mole = 6.022 x 10²³ elementary entities.

These number of elementary entities in 1 mole is equal to or called as an Avogadro's number.  Mole is equal to 6.022 x 10²³ because this number of entity is same as in exactly 12 g of carbon-12.

It is a very important SI unit of measured which is used by the chemists. Moles are used in measuring in small or tiny things such as atoms, molecules and the other tiny particles.

To learn more about the mole concept,

brainly.com/question/28498715

#SPJ4

3 0
1 year ago
Helium does not usually react with other substances. Does this mean that helium has no chemical properties? Explain.
Sedaia [141]
Everything has chemical properties it depends on the reactivity and the reactivity of the other element and what form it is in
3 0
3 years ago
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