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Alja [10]
3 years ago
14

Chemistry test!!! no fake answers please and if you can explain then do it because I need all the help I can get!

Chemistry
1 answer:
ivanzaharov [21]3 years ago
8 0

Answer:

(−ΔH°1)+12(−ΔH°2)+(ΔH°3)+(ΔH°4)

I hope this helps you out!! :)

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The chart indicates the time, speed, and velocity of five runners.
Vitek1552 [10]

Answer:

garreth is the fasstis runner

luigi is the 2 fasts runner

elisa is the 3 fastes runner

Explanation:

3 0
3 years ago
1.
Serhud [2]

Explanation:

Given that,

The frequency of electromagnetic spectrum is 2.73\times 10^{16}\ Hz

(A) Let the wavelength of this radiation is \lambda. We know that,

c=f\lambda\\\\\lambda=\dfrac{c}{f}\\\\\lambda=\dfrac{3\times 10^8}{2.73\times 10^{16}}\\\\\lambda=1.09\times 10^{-8}\ m

So, the wavelength of this radiation is 1.09\times 10^{-8}\ m.

(B) Let E is the energy associated with this radiation. Energy of an electromagnetic radiation is given by :

E=hf

h is Planck's constant

E=6.63\times 10^{-34}\times 2.73\times 10^{16}\\\\E=1.8\times 10^{-17}\ J

1 kcal = 4184 J

It means,

1.8\times 10^{-17}\ J=\dfrac{1}{4184}\times 1.8\times 10^{-17}\\\\=4.3\times 10^{-21}\ \text{kcal}

Hence, this is the required solution.

3 0
3 years ago
Determining Density and Using Density to Determine Volume or Mass
Shalnov [3]

corrected question:

Determining Density and Using Density to Determine Volume or Mass

(a) Calculate the density of mercury if 1.00 × 10 g occupies a volume of 7.36 cm³

(b) Calculate the volume of 65.0 g of liquid methanol (wood alcohol) if its density is 0.791 g/mL.

(c) What is the mass in grams of a cube of gold (density = 19.32 g/cm) if the length of the cube is 2.00 cm?

(d) Calculate the density of a 374.5-g sample of copper if it has a volume of 41.8 cm³ A student needs 15.0 g of ethanol for an experiment. If the density of ethanol is 0.789 g/mL, how many milliliters of ethanol are needed? What is the mass, in grams, of 25.0 mL of mercury (density = 13.6 g/mL)?

Answer:

density = \frac{mass}{volume}

ρ=m/v ,m=ρv,    v=m/ρ

(a)m=1*10g  , v=7.36cm³

    ρ=10/7.36 =1.36g/cm³

(b) m=65g, ρ=0.791 g/mL.

   v= 65/0.791 =82.17g/mL

(c) ρ=19.32g/cm³, l=2cm, v=l³=8cm³

    m=19..32*8=154.56g/cm³

(d) mass of copper=374.5g , v=41.8cm³

   ρ=374.5/41.8 =8.96g/cm³

 mass of ethanol=15g,  density of ethanol=0.789g/mL

v=15/0.789 =19.01mL

volume of mecury=25mL, density of mercury=13.6g/mL

m=25*13.6=340g

4 0
3 years ago
A chemist requires 0.802 mol Na2CO3 for a reaction. How many grams does this correspond to?
Komok [63]

Answer:

Ok:

Explanation:

So grams = mols*MolarMass. Here, MolarMass (MM) = 105.99g which can be found using the periodic table. mols is given to be 0.802. We can then plug in to get that it corresponds to 85.0g.

7 0
2 years ago
Which of the following expressions best represents a second order rate law?
Ksivusya [100]
I think the correct answer would be C. The expression that would best represent a second order rate law would be r =k[X][Y]. Reaction with this rate law are those that depend on the concentration of two first order reactants or a second order reactant.
8 0
3 years ago
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