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2 years ago

During which stage of the cell cycle dies the cell condense chromosomes and break down the nuclear envelope

Chemistry

1 answer:

saveliy_v [14]2 years ago

5 0

Answer:

Prophase

Explanation:

During prophase, the chromosomes condense, the nucleolus disappears, and the nuclear envelope breaks down.

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A laser used to read CDs emits red light of wavelength 700 nm. How many photons does it emit each second if its power is?(a) 0.1

Elenna [48]

power = work/time

watt = joule/sec

a) power = 0.10 watt = 0.1joules/sec

work = power * time

= 0.10 * 1 =0.1joules

work is northing but energy

therefore energy is 0.1joules

according to planks quantum theory E = nhν where nis the no. of photons ; h is planks constant; ν isfrequency

hence, n = E/hν

or n = Eλ/hc (ν = c/λ)

n = (0.1*700*10^-9)/6.625*10^-34*3*10^8 = 0.3522*10^18photons

b) similar to the above calculation

here E = 1.0joules

n = (1.0*700*10^-9)/6.625*10^-34*3*10^8 = 0.3522*10^17photons

4 0

3 years ago

Water is a source of ______________ for chemical reactions in cells.

S_A_V [24]

Answer:Electrolyte

Explanation:Electrolyte is a compound either in solution or in molten form that gets decomposed by thee passage if electricity through it. Water is polar,but a weak electrolyte, so in cells,water is used as an electrolyte

5 0

2 years ago

Dissolution of KOH, ΔHsoln:

swat32

Using Hess's law we found:

1) By adding reaction 10.2 with the reverse of reaction 10.1 we get reaction 10.3:

KOH(aq) + HCl(aq) → H₂O(l) + KCl(aq) ΔH (10.3)

2) The ΔHsoln must be subtracted from ΔHneut to get the total change in enthalpy (ΔH).

The reactions of dissolution (10.1) and neutralization (10.2) are:

KOH(s) → KOH(aq) ΔHsoln (10.1)

KOH(s) + HCl(aq) → H₂O(l) + KCl(aq) ΔHneut (10.2)

1) According to Hess's law, the total change in enthalpy of a reaction resulting from differents changes in various reactions can be calculated as the sum of all the enthalpies of all those reactions.

Hence, to get reaction 10.3:

KOH(aq) + HCl(aq) → H₂O(l) + KCl(aq) (10.3)

We need to add reaction 10.2 to the reverse of reaction 10.1

KOH(s) + HCl(aq) + KOH(aq) → H₂O(l) + KCl(aq) + KOH(s)

Canceling the KOH(s) from both sides, we get reaction 10.3:

KOH(aq) + HCl(aq) → H₂O(l) + KCl(aq) (10.3)

2) The change in enthalpy for reaction 10.3 can be calculated as the sum of the enthalpies ΔHsoln and ΔHneut:

$\Delta H = \Delta H_{soln} + \Delta H_{neut}$

The enthalpy of reaction 10.1 (ΔHsoln) changed its sign when we reversed reaction 10.1, so:

$\Delta H = \Delta H_{neut} - \Delta H_{soln}$

Therefore, the ΔHsoln must be subtracted from ΔHneut to get the total change in enthalpy ΔH.

Learn more here:

brainly.com/question/2082986?referrer=searchResults

brainly.com/question/1657608?referrer=searchResults

I hope it helps you!

6 0

2 years ago

1. How is the modern periodic table organized?

Dimas [21]

1. How is the modern periodic table organized? Increasing atomic number

2. What information about an atom's properties can you read from the periodic table? Metal or not metal. Does it want to gain or lose electrons

3. How are the relationships of elements in a group different from the relationships of elements in a period? a group will have similar properties A period will have different properties

4. Would you expect Strontium (Sr) to be more like potassium (K) or bromine (Br)?

potassium

5. Barium (Ba) is in Group 2. Recall that atoms in Group 1 lose one electron to form ions with a 1+ charge. What type of ion does barium form? Ba+2

3 0

3 years ago

What is the total number of moles represented by 20 grams of CACO3

Nutka1998 [239]

Answer:

B. 0.2.

Explanation:

We can use the relation:

n = mass/molar mass

mass of CaCO₃ = 20 g, molar mass of CaCO₃ = 100.0869 g/mol.

∴ n = mass/molar mass = (20 g)/(100.0869 g/mol) = 0.1998 ≅ 0.2 mol.

So, the right choice is: B. 0.2.

8 0

3 years ago