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V125BC [204]
3 years ago
6

Please help, I'm confused and it's due very soon!

Chemistry
1 answer:
ryzh [129]3 years ago
3 0

Answer:

1. Lanthanum-139 atom is the stable isotope of lanthanum with relative atomic mass 138.906348, 99.9 atom percent natural abundance and nuclear spin 7/2.

2. In fact, over 80% of electric cars sold globally utilized permanent magnet-based motors in 2019. These magnets are typically made with rare-earth materials such as neodymium and dysprosium, which have a very geographically constrained supply chain.

3. It is the second most reactive of the rare-earth metals after europium. Lanthanum oxidizes in air at room temperature to form La2O3. It slowly reacts with water and quickly dissolves in diluted acids, except hydrofluoric acid (HF) because of formation of a protective fluoride (LaF3) layer on the surface of the metal.

Explanation:

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Sunita carries out an experiment to investigate diffusion. She uses water and a food dye to find out how the volume of water use
Phantasy [73]

Answer:

Sunita will change the variable water.

Explanation:

Sunita have to change the variable water to perform this experiment of diffusion.This is because she is going to predict that more water she uses longer the time needed for the dye to spread through it.

 As a result she is increasing the amount of water to observe the effect of diffusible substance on diffusion with time.

6 0
4 years ago
Which statement correctly describes protons? They have no charge and are present in the nucleus of an atom. They have a negative
Kamila [148]
AnswerD is the correct answer. for your information, A describes the neutrons and B describes the electrons. C is wrong.
5 0
3 years ago
Read 2 more answers
Which coefficients will balance the following reaction:
valentina_108 [34]

Answer:

C ) 2, 1, 2

Explanation:

The given reaction is synthesis reaction in which lithium and bromine react to form lithium bromide.

Chemical equation:

Li + Br₂    →    LiBr

Balanced chemical equation:

2Li + Br₂    →    2LiBr

Step 1:

Li + Br₂    →    LiBr

left hand side                         Right hand side

Li = 1                                        Li = 1

Br = 2                                        Br = 1

Step 2:

Li + Br₂    →    2LiBr

left hand side                         Right hand side

Li = 1                                        Li = 2

Br = 2                                        Br = 2

Step 3:

2Li + Br₂    →    2LiBr

left hand side                         Right hand side

Li = 2                                       Li = 2

Br = 2                                        Br = 2

3 0
3 years ago
What is the mass (in grams) of 9.93 Ă— 1024 molecules of methanol (CH3OH)?
WINSTONCH [101]

Answer is: mass of methanol is 528.32 grams.

N(CH₃OH) = 9.93·10²⁴; number of methanol molecules.

n(CH₃OH) = N(CH₃OH) ÷ Na (Avogadro constant).

n(CH₃OH) = 9.93·10²⁴ ÷ 6.022·10²³ 1/mol.

n(CH₃OH) = 16.49 mol; amount of substance.

m(CH₃OH) = n(CH₃OH) · M(CH₃OH).

m(CH₃OH) = 16.49 mol · 32.04 g/mol.

m(CH₃OH) = 528.32 g.

7 0
3 years ago
What is the shortest wavelength in the Balmer series
MissTica
The largest energy release will take place when the electron jumps between the greatest number of levels. In this case from infinity down to 2 

This is the emitted photon with the most energy ( in the Balmer series), the highest frequency and therefore the shortest wavelength. 

Balmer's original formula was 

Wavelength = 3645.6 . 10^–10 ( n^2 / (n^2 – 4) ) 

When n => infinity 

Wavelength = 3.6456 . 10^–7 m ( or 364.5 nm)
7 0
3 years ago
Read 2 more answers
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