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raketka [301]
2 years ago
6

Which is correct if 15,390,000 is rounded to two significant figures?

Chemistry
1 answer:
BARSIC [14]2 years ago
7 0

Answer:

Explanation:

Remark

This is one of those questions that you need the choices. You can't tell what you should enter. For example, in scientific notation, you would get 1.5*10^7.

Or you could keep it as an integer and round to two places 150,000,000,

I would pick scientific notation if you know how to use it. Otherwise use the interger format.

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Can someone pls help me I will mark you as brain
vladimir2022 [97]

Answer:

Both Options C and D are appropriate.

But I'd go with Option D since "Direct Air Capture" would eventually lead to "Ground Injection"

OPTION D.

3 0
3 years ago
What are ionic bonds composed of?
Sonbull [250]

Answer:Ionic compounds are compounds composed of ions, charged particles that form when an atom (or group of atoms) gains or loses electrons. (A cation is a positively charged ion; an anion is a negatively charged ion.) Covalent or molecular compounds form when elements share electrons in a covalent bond to form molecules.

8 0
3 years ago
Read 2 more answers
(The radioisotope 224Ra decays by alpha emission via two paths to the ground state of its daughter 94% probability of alpha deca
pav-90 [236]

Answer:

a) ²²⁴Ra₈₈ ---> α + ²²⁰Rn₈₆ + Q

b) the Q-value of this reaction is 5.789 MeV

c) the energies (in MeV) of the two associated alpha particles are; 5.69 MeV and 5.449 Mev

       

Explanation:

a)

The decay equation for the alpha decay is expressed as;

²²⁴Ra₈₈ ---> α + ²²⁰Rn₈₆ + Q

b)

Calculate the Q-value (in MeV) of this reaction.

Q = Mparent - Mdaughter -Mg

Q = MRa - MRn -Mg

= 224.020202 - 220.011384 - 4.00260305

= 0.00621495 amu

= 5.789 MeV

therefore the Q-value of this reaction is 5.789 MeV

c)

Energy of alpha particle is expressed as;

E∝ = MQ / ( m + M)

now this is the maximum energy available for the daughter, ²²⁰Rn going to the ground state;

The energy of the alpha particle gives;

E∝  = 220(5.789) / ( 4 + 220) = 5.69 MeV

as given in the question,The other less frequent alpha occurring 5.5% of the time leaves the daughter nucleus in an excited state of 0.241 MeV above the ground state.

Therefore the energy of this alpha is

E∝ = 5.69 - 0.241 = 5.449 Mev

Therefore the energies (in MeV) of the two associated alpha particles are; 5.69 MeV and 5.449 Mev

d)

Sketch of the nuclear decay scheme have been uploaded along side this answer.

7 0
3 years ago
53. Which of the following is NOT a correct interpretation of CH2O, the formula of the compound formaldehyde?
Free_Kalibri [48]

Answer:

B There are two grams of hydrogen for each gram of carbon in this compound.

Explanation:

The second option is a wrong interpretation of this chemical representation of formaldehyde.

Formaldehyde is an organic compound with the formula CH₂O.

As this is the simplest formula of the compound, it is the empirical formula. Also, the formula is the actual one for the compound and it is the molecular formula.

Chemically, the formula shows 1 mole of carbon, 2 moles of H and 1 mole of oxygen in the compound.

  • A mole of a substance is more a less a unit of measurement in chemistry and it is the amount of substance that contains the avogadro's number of particles.

This ratio is not the mass of chemical species in the compound. You cannot tell the mass of elements in a compound by merely looking at the formula.

7 0
3 years ago
The presence of which of the following substances can allow a chain reaction to happen?
vlada-n [284]

Answer:

im not sure either B or D b is the only one with evidence

Explanation:

Most chemical chain reactions have very reactive intermediates called free radicals. The intermediate that maintains the chain reaction is called a chain carrier. These atoms or fragments are usually derived from stable molecules due to photo- or heat-dissociation

5 0
3 years ago
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