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inessss [21]
4 years ago
14

how many grams of antifreeze would be required per 500 g of water to prevent the water from feezing at a temperature of -39° C​

Chemistry
1 answer:
andrezito [222]4 years ago
4 0

Answer:

333.7g of antifreeze

Explanation:

Freezing point depression in a solvent (In this case, water) occurs by the addition of a solute. The law is:

ΔT = Kf × m × i

Where:

ΔT is change in temperature (0°C - -20°C = 20°C)

Kf is freezing point depression constant (1.86°C / m)

m is molality of solution (moles solute / 0.5 kg solvent -500g water-)

i is Van't Hoff factor (1, assuming antifreeze is ethylene glycol -C₂H₄(OH)₂)

Replacing:

20°C = 1.86°C / m  × moles solute / 0.5 kg solvent × 1

5.376 = moles solute

As molar mass of ethylene glycol is 62.07g/mol:

5.376 moles × (62.07g / 1mol) = <em>333.7g of antifreeze</em>.

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Hurry PLEASE HELP!
avanturin [10]

B. 11,540

<h3>Further explanation </h3>

The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.  

Usually radioactive elements have an unstable atomic nucleus.  

General formulas used in decay:  

\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}

T = duration of decay  

t 1/2 = half-life  

N₀ = the number of initial radioactive atoms  

Nt = the number of radioactive atoms left after decaying during T time  

Nt=25 g

No=100 g

t1/2=5770 years

\tt 25=100\dfrac{1}{2}^{T/5770}\\\\\dfrac{1}{4}=\dfrac{1}{2}^{T/5770}\\\\2=T/5770\rightarrowT=11540~years

7 0
3 years ago
Needing help please help me
Elenna [48]

Answer:

18. E. 0%

19. D. 25%

Explanation:

Question 18:

Let's use "B" to represent the dominant allele of "light blue skin", and

"b" for recessive "light green skin".

Squidward => BB - light blue skin

Squidward's bride => bb - light green skin

When they cross, they will have the following offsprings:

(BB) × (bb) - Parent

(Bb) (Bb) (Bb) (Bb) - Offspring

All the offspring would be light green skin. The dominant allele of light green skin will express itself over the recessive allele.

Therefore, the chances of Squidward and his bride having light green skin is 0%

Question 19:

Squidward's son => Bb - light blue skin

Squidward's son's bride => Bb - light blue skin

(Bb) × (Bb) - parent

(BB) (Bb) (Bb) (bb) - offspring

They will have the following offspring:

BB and Bb - light blue - 75%

bb - light green - 25%

Chance of having offspring with light green skin is 25%

8 0
3 years ago
What do a mole of magnesium (Mg) and a mole of iron (Fe) have in common?
azamat
What they have in common is that they both have the same number of atoms.
9 0
3 years ago
This is due at 2:00 am today. I only have a few points. No links please I need a real answer.
GuDViN [60]

Answer:

7.5 g of AlCl3

Explanation:

The given equation is;

NaOH + AlCl3 --> Al(OH)3 + NaCI.

By inspection, it is not balanced because OH and Clare not equal on both sides of the equation.

Thus, let's make them equal by balancing the equation.

Cl has 3 on the left, so we will make it to have 3 on the right. Same thing with OH on the right and we will make it to have 3 on the left. Thus:

3NaOH + AlCl3 --> Al(OH)3 + 3NaCI

We can see that;

NaOH has 3 moles

While AlCl3 has 1 mole

Thus, to find how many grams of AlCl3 will be required to completely react with 2.25g of NaOH ;

2.25g of NaOH × (3 moles NaOH/39.997 g/mol of NaOH) × (1 mole of AlCl3/3 moles of NaOH) × (133.34 g/mol of AlCl3/1 mol AlCl3) = 7.5 g of AlCl3

5 0
3 years ago
In which of the following is the number of electrons the ion contains given correctly
larisa [96]

Answer:

B. K+ has 18 electrons

Explanation:

  • Ions are formed when atoms of element gain or loose electrons.
  • <em><u>When an atom looses electrons it forms a positively charged ion and when an atom gains electrons it forms a negatively charged ion.</u></em>
  • Metal atoms such as potassium, magnesium and aluminium looses outer most electrons to positively charged ions.
  • <u>Potassium atom has 19 electrons, 19 protons, with an electronic configuration of 2 : 8 : 8 : 1.</u> <u><em>To form an ion, K looses an electron to form a positively charged potassium ion (K+) with 18 electrons and 19 protons and an electronic configuration of 2:8:8.</em></u>
8 0
3 years ago
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