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3 years ago

Help me please someone?

Chemistry

1 answer:

ElenaW [278]3 years ago

3 0

It could both the 2nd and the 3rd,
because if you add the exponents (2 + 1 + 6 = 9) you don't get 10.
and also each orbital level can and has to carry 2 electrons, and the 2s only has 1 there.

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What role do guanacos play in the Andes Mountains ecosystem?.

Nikitich [7]

Grasses and plants are producers, guanacos are herbivores and are primary consumers and pumas are predators and secondary consumers

5 0

2 years ago

How many grams of copper (II) hydroxide can be prepared from 2.4 grams of copper (II) nitrate (Cu(NO3)2 ) and excess sodium hydr

andreyandreev [35.5K]

Answer:

percentage yield = 67%

Explanation:

Mass of Cu(NO₃)₂ = 15.25 g

Mass of NaOH = 12.75 g

Percentage yield = ?

Solution:

Cu(NO₃)₂ + 2NaOH → Cu(OH)₂ + 2NaNO₃

Moles of Cu(NO₃)₂:

Number of moles = mass/ molar mass

Number of moles = 15.25 g /187.56 g/mol

Number of moles = 0.08 mol

Moles of NaOH :

Number of moles = mass/ molar mass

Number of moles = 12.75 g / 40 g/mol

Number of moles = 0.32 mol

Now we will compare the moles of Cu(OH)₂ with NaOH and Cu(NO₃)₂. NaOH : Cu(OH)₂

2 : 1

0.32 : 1/2×0.32 = 0.16 mol

Cu(NO₃)₂ : Cu(OH)₂

1 : 1

0.08 : 0.08

The number of moles produced by Cu(NO₃)₂ are less so it will limiting reactant.

Mass of Cu(OH)₂:

Mass = number of moles × molar mass

Mass = 0.08 mol × 97.6 g/mol

Mass = 7.808 g

Theoretical yield = 7.808 g

Percent yield:

percentage yield = Actual yield/ theoretical yield × 100

percentage yield = 5.23 g/ 7.808 g × 100

percentage yield = 0.67 × 100

percentage yield = 67%

5 0

2 years ago

3 organisms that help prevent infections

love history [14]

Infection control is the discipline concerned with preventing nosocomial or healthcare-associated infection, a practical (rather than academic) sub-discipline of epidemiology. It is an essential, though often underrecognized and undersupported, part of the infrastructure of health care. Infection control and hospital epidemiology are akin to public health practice, practiced within the confines of a particular health-care delivery system rather than directed at society as a whole. Anti-infective agents include antibiotics, antibacterials, antifungals, antivirals and antiprotozoals.[1]

Infection control addresses factors related to the spread of infections within the healthcare setting (whether patient-to-patient, from patients to staff and from staff to patients, or among-staff), including prevention (via hand hygiene/hand washing, cleaning/disinfection/sterilization, vaccination, surveillance), monitoring/investigation of demonstrated or suspected spread of infection within a particular health-care setting (surveillance and outbreak investigation), and management (interruption of outbreaks). It is on this basis that the common title being adopted within health care is "infection prevention and control." (got from google

8 0

3 years ago

Acetylene gas (ethyne; HC = CH) burns in an oxyacetylene torch to produce carbon dioxide and water vapor. The heat of reaction f

Yanka [14]

The mass of CO2 produced by 26g of acetylene is 88g.

Given ,

In an oxyacetylene torch, acetylene gas (ethyne; HCCH) burns to produce carbon dioxide and water vapour.

The acetylene combustion reaction is given by,

H2O + HCCH + 5/2 O=O 2CO2

Heat of reaction for acetylene combustion = 1259kj/mol

CO2 has a molecular mass of 44g/mol.

2 moles of CO2 have a molecular mass of 88g.

On combustion, 1 mole of acetylene yields 2 moles of CO2.

Thus, 26g of acetylene produces 88g of CO2 when burned.

As a result, the mass of carbon dioxide produced by 26g of acetylene is 88g.

Learn more about acetylene here :

brainly.com/question/15346128

#SPJ4

6 0

1 year ago

The hybridization for the B in Bcl3 is ?

Phoenix [80]

Answer:

sp²

Explanation:

You need to look at how many electron orbitals around the atom. Looking at the structure below, you can see that there are three electron orbitals. This gives you an sp² hybridization.

6 0

3 years ago