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3 years ago

Please answer this I need it answered really soon thank you so much whoever answers this and I will give BRAINLIEST!!

Chemistry

2 answers:

max2010maxim [7]3 years ago

3 0

Answer:

B extinction

Explanation:

as the species does not exist any more, the species is extinct, therefore making the pictured fossil of an extinct species

hope this helps

LiRa [457]3 years ago

3 0

Answer:

Explanation:

As the species no longer exists, it is an example of extinction, the termination of a species.

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Can you please help with question 1 and 4

larisa86 [58]

Answer:

i) 24.305 u

iv) The number of protons determines an element's atomic number and is used to distinguish one element from another.

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3 years ago

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When sodium is excited in a flame, two ultraviolet spectral lines at lambda - 372.1 nm and lambda = 376.4 nm respectively are em

suter [353]

The wavelength that represented photons is at lambda = 376.4 nm.
The wavelength with the higher energy is at lambda - 372.1 nm.
The longer wavelength is, of course, at lambda 376.4 nm.
The wavelength with the higher frequency is 376.4 nm.

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3 years ago

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Cryolite (Na3AlF6) is used in the production of aluminum from its ores. It is made by the reaction 6 NaOH 1 Al2O3 1 12 HF 8n 2 N

kap26 [50]

Answer: The mass of cryolite produced in the reaction is 1181.8 g

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

Given mass of aluminium oxide = 287 g

Molar mass of aluminium oxide = 102 g/mol

Putting values in equation 1, we get:

$\text{Moles of aluminium oxide}=\frac{287g}{102g/mol}=2.814mol$

The given chemical reaction follows:

$6NaOH+Al_2O_3+12HF\rightarrow 2Na_3AlF_6+9H_2O$

By Stoichiometry of the reaction:

1 mole of aluminium oxide produces 2 moles of cryolite

So, 2.814 moles of aluminium oxide will produce = $\frac{2}{1}\times 2.814=5.628mol$ of cryolite

Now, calculating the mass of cryolite by using equation 1:

Moles of cryolite = 5.628 moles

Molar mass of cryolite = 210 g/mol

Putting values in equation 1, we get:

$5.628mol=\frac{\text{Mass of cryolite}}{210g/mol}\\\\\text{Mass of cryolite}=(5.628mol\times 210g/mol)=1181.8g$

Hence, the mass of cryolite produced in the reaction is 1181.8 g

5 0

3 years ago

The Henry's law constant (kH) for O2 in water at 20°C is 1.28e-3 mol/l atm. How many grams of O2 will dissolve in 3.5 L of H2O t

Sophie [7]

Answer : The mass of $O_2$ dissolved will be, 0.2365 grams

Explanation :

First we have to calculate the concentration of $O_2$ .

As we know that,

$C_{O_2}=k_H\times p_{O_2}$

where,

$C_{O_2}$ = concentration of $O_2$ = ?

$p_{O_2}$ = partial pressure of $O_2$ = 1.65 atm

$k_H$ = Henry's law constant = $1.28\times 10^{-3}mole/L.atm$

Now put all the given values in the above formula, we get:

$C_{O_2}=(1.28\times 10^{-3}mole/L.atm)\times (1.65atm)$

$C_{O_2}=2.112\times 10^{-3}mole/L$

The concentration of $O_2$ = $2.112\times 10^{-3}mole/L$

Now we have to calculate the moles of $O_2$

$\text{Moles of }O_2=\text{Concentration of }O_2\times \text{volume of solution}$

$\text{Moles of }O_2=(2.112\times 10^{-3}mole/L)\times (3.5L)=7.392\times 10^{-3}mole$

Now we have to calculate the mass of $O_2$

$\text{Mass of }O_2=\text{Moles of }O_2\times \text{Molar mass of }O_2$

$\text{Mass of }O_2=(7.392\times 10^{-3}mole)\times (32g/mole)=0.2365g$

Therefore, the mass of $O_2$ dissolved will be, 0.2365 grams

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3 years ago

A molecule of antifreeze, ethylene glycol, has the formula c2h4(oh)2. how many atoms are there in one molecule of antifreeze?

kifflom [539]

Answer is: there are ten atoms in one molecule of antifreeze.
One molecule of ethylene glycol (C₂H₄(OH)₂) has two carbon atoms, six hydrogen atoms (4 + 2 · 1) and two oxygen atoms (2 · 1). So there are:
2 + 6 + 2 = 10 atoms.
Ethylene glycol (C₂H₄(OH)₂) is an odorless, sweet-tasting, colorless viscous liquid.

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3 years ago

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