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3 years ago

Fireweed is often one of the first plants to grow after a forest fire or volcanic eruption. What adaptation might fireweed have?

Chemistry

1 answer:

SSSSS [86.1K]3 years ago

8 0

I think it has the ability to survive in cold temperatures as it grows mostly in colder months

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A typical aspirin tablet contains 5.00 grains of pure aspirin analgesic compound. The rest of the tablet is

Pavel [41]

Answer:

$Tablets=193$

Explanation:

Hello,

In this case, given that a typical aspirin tablet contains 5.00 grains of pure aspirin, the first step here is to compute the mass of those grans per tablet given that 1.00 g = 15.4 grains:

$m=5.00grains*\frac{1.00g}{15.4grains}=0.325g$

In such a way, the number of aspirin tablets are computed considering the total mass of aspirin and the mass per tablet:

$Tablets=\frac{62.7g}{0.325g}\\ \\Tablets=193$

Best regards.

8 0

3 years ago

2. Given the unbalanced equation:

zheka24 [161]

2 Na + 2 H2O → 2 NaOH + H2 (balanced equation)
The answer would be 2, since 2 in the coefficient of both Na and NaOH

7 0

3 years ago

A solution of sodium chloride in water has a vapor pressure of 19.6 torr at 25°C. What is the mole fraction of NaCl in this solu

Debora [2.8K]

Answer:

Mole fraction of Nacl is 0.173

Explanation:

we know that

$P_{sol}=\chi_{solvent}P^0_{solvent}$

where,

P sol - the vapor pressure of the solution

χ solvent - the mole fraction of the solvent

P ∘ solvent - the vapor pressure of the pure solvent

This means that in order to be able to calculate the mole fraction of sodium chloride, you need to know what the vapor pressure of pure water is at

25 ° C You can use an online calculator to find that the vapor pressure of pure water at 25 C is equal to about 23.8 torr .

$\chi_{water}= \frac{P{sol}}{P^0{water}}$

$\chi_{water}= \frac{19.6}{23.8}$

=0.827

Also we know that

$\chi_{water}+\chi_{Nacl}= 1$

This means that the mole fraction of sodium chloride is

χ_{Nacl}= 1-Χ_{water}

= 1-0.827 =0.173

3 0

3 years ago

Round off the following to three significant figures 0.032000000cg

tino4ka555 [31]

0.032000000 cg

Rounding off ........>

0.0320 cg

The last zero means the measurement is accurate to that digit

6 0

3 years ago

Given the following at 25C calculate delta Hf for HCN (g) at 25C. 2NH3 (g) +3O2 (g) + 2CH4 (g) ---> 2HCN (g) + 6H2O (g) delta

AysviL [449]

Answer: The $\Delta H_f$ for HCN (g) in the reaction is 135.1 kJ/mol.

Explanation:

Enthalpy change is defined as the difference in enthalpies of all the product and the reactants each multiplied with their respective number of moles. The equation used to calculate enthalpy change is of a reaction is:

$\Delta H_{rxn}=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)]$

For the given chemical reaction:

$2NH_3(g)+3O_2(g)+2CH_4(g)\rightarrow 2HCN(g)+6H_2O(g)$

The equation for the enthalpy change of the above reaction is:

$\Delta H_{rxn}=[(2\times \Delta H_f_{(HCN)})+(6\times \Delta H_f_{(H_2O)})]-[(2\times \Delta H_f_{(NH_3)})+(3\times \Delta H_f_{(O_2)})+(2\times \Delta H_f_{(CH_4)})]$

We are given:

$\Delta H_f_{(H_2O)}=-241.8kJ/mol\\\Delta H_f_{(NH_3)}=-80.3kJ/mol\\\Delta H_f_{(CH_4)}=-74.6kJ/mol\\\Delta H_f_{(O_2)}=0kJ/mol\\\Delta H_{rxn}=-870.8kJ$

Putting values in above equation, we get:

$-870.8=[(2\times \Delta H_f_{(HCN)})+(6\times (-241.8))]-[(2\times (-80.3))+(3\times (0))+(2\times (-74.6))]\\\\\Delta H_f_{(HCN)}=135.1kJ$

Hence, the $\Delta H_f$ for HCN (g) in the reaction is 135.1 kJ/mol.

8 0

3 years ago