Write the isotope notation for an element with 12 protons and 14 neutrons.

The noble-gas notation for tin (Sn) will contain the symbol

Tanzania [10]

The noble gas notation is as follows- you must start with the noble gas that is before the element which in this case is Krypton and then from there you continue the electron configuration as follows- [Kr] 5s^2 4d^10 5p^2

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3 years ago

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Which two ions have the same electron configuration?

djverab [1.8K]

Answer: A) Na+ and O2-

Explanation:

To know the electronic configuration, one has to determine the numbers of electrons present in each atom.

Na+ means a sodium atom that has lost one valence electron. A Sodium atom initially has 11 electrons, but having lost an electron making it 10 electrons remaining with electron configuration of 1s2 2s2 2p6.

O2- means oxygen atom that has gained two valence electrons. An oxygen atom initially has 8 electrons, having gained two electrons makes it 10 electrons with electron configuration of 1s2 2s2 2p6. same as Na+

The purpose of gaining or losing electrons is to attain a stable duplet or octet structure.

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3 years ago

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You need to prepare an acetate buffer of pH 5.36 from a 0.900 M acetic acid solution and a 2.62 M KOH solution. If you have 680

Alexus [3.1K]

Answer:

Explanation:

pH = pKa + log [ CH₃COO⁻ ] / [CH₃COOH ]

5.36 = 4.86 + log [ CH₃COO⁻ ] / [CH₃COOH ]

log [ CH₃COO⁻ ] / [CH₃COOH ] = .5

[ CH₃COO⁻ ] / [CH₃COOH ] = 3.16

moles of CH₃COOH = .680 x .9 = .612 M

Let x mole of KOH is required

x /( .612 - x ) = 3.16

x = 1.933 - 3.16 x

x = .46488

.46488 moles of KOH will be required

volume required be V

v x 2.62 = .46488

v = .1774 L

= 177.4 mL

177.4 mL of 2.62 M KOH will be required .

6 0

3 years ago

If you need to reverse the following reaction in order for it to be an intermediate reaction in a Hess's law problem, what would

Olin [163]

When reversing a given reaction, we simply change the sign of the standard enthalpy change value. Therefore, the reaction will become:
H₂O → H₂ + 0.5O₂, ΔH = 286kJ
This is because if a certain amount of energy is released when a reaction occurs, the same amount of energy must be supplied for the reaction to occur in the reverse direction.

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3 years ago

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Please helpp neep asap ik its late at night but i just need this one page and i can rest

stich3 [128]

Answer:

15. Velocity = 3 X 10^8

Distance = 1580 m

time = distance / velocity

t = 1580 / 3 * 10^8

t = 1580 * 10^-8 / 3

t = 158 * 10^-7/3

t = 5.26 * 10^-8 seconds

16. Converting the distance to 'm'

Given distance (in miles), multiplying by 1.609 to convert to km and also multiplying by 1000 to convert to 'm'

s= 4.8 * 1.609 * 10^7 * 1000

v = 3 * 10^8

t = 4.8 * 1609 * 10^7 / 3 * 10^8

t = 1.6 * 1609 * 10^-1

t = 2574.4 * 10^ -1

t = 2.5744 * 10^-4 s

17. Mass in 1 tsp of medicine = 5 mL at a density of 25 mg/mL

Mass in 1 tsp of medicine = 5 * 25 = 125 mg

Mass prescribed by the doctor = 375 mg

Number of table spoons required = Mass prescribed / Mass in 1 tsp

N = 375/125 = 3 table spoons of the medicine

18. Density of medicine = 400g/ 5mL = 80g / mL

Medicine required = 1500 g

Volume of medicine required = Medicine Required / Density of medicine

Volume = 1500 / 80 = 18.75 mL of medicine is required

Hence, the volume of the suspension should be at least 18.75 mL

19. Volume of 10 drops = 1 mL

Volume of 5 drops = 1/2 mL

The faucet is leaking 5 drops or 1/2 mL water per minute

Number of minutes in a day = 60 * 24 = 1440 minutes in a day

Water leaked in 1440 minutes = 1440 * 1/2 = 720

0.720 L (720 mL) Water leaked from the faucet in a day

Kindly mark Brainliest, Thanks

8 0

4 years ago