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kondor19780726 [428]
3 years ago
14

Which method is most likely used to identify what happened before the start of the paleozoic era?

Chemistry
2 answers:
vodka [1.7K]3 years ago
6 0
Scientist examine fossil evidence during the pre-time yes researching about the things at the pre-Cambrian time might help them to identify what would’ve happened before Paleozoic era
earnstyle [38]3 years ago
5 0

Answer:C

Explanation:

on edge

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Where do freshwater come from
saul85 [17]

Answer:

Fresh water is found in glaciers, lakes, reservoirs, ponds, rivers, streams, wetlands, and even groundwater.

3 0
3 years ago
Lewis structures for the perchlorate ion (ClO4−) can be drawn with all single bonds or with one, two, or three double bonds. Dra
Vanyuwa [196]

Answer:

The most important resonance structure is 4 (attached picture). Its bon order is \frac{7}{4} or 1\frac{3}{4}.

Explanation:

A picture with 4 forms of the perchlorate structure is attached. The first structure has simple bonds. The second structure contains a double bond, the third structure has two double bonds and the fourth structure has three double bonds.

Formal charge = group number of the periodic table - number of bonds (number of bonding electrons / 2) - number of non-shared electrons (lone pairs)

The formal charges in the first structure is +3 in chlorine and -1 in oxygen.

The formal charges in the second structure is +2 in chlorine, -1 in oxygen and 0 in the double bond oxygen.

The formal charges in the third structure is +1 in chlorine, -1 in the single bond oxygens and 0 in the double bond oxygens.

The formal charges in the fourth structure is 0 in chlorine, -1 in the single bond oxygen and 0 in the double bond oxygens.

The most important resonance structure is given by:

  • Most atoms have 0 formal charge.
  • Lowest magnitude of formal charges.
  • If there is a negative formal charge, it's on the most electronegative atom.

Hence, the fourth structure is the mosr important.

The bond order of the structure is:

Total number of bonds: 7

Total number of bond groups: 4

Bond order= \frac{7}{4} =1\frac{3}{4}

5 0
3 years ago
What type of claim must be supported by scientifically valid evidence for it to be approved for use on a food label? A. Health c
Lelu [443]
Option A. Health claim

Health claim must be supported by scientifically valid evidence to be approved in using  for food label.

This is also a food guide to all consumers the food content implied by manufacturers to their products.
8 0
4 years ago
Read 2 more answers
Durante 50 s un cuerpo viaja a una velocidad de 18.5 m/s, ¿Qué distancia recorrió?
weeeeeb [17]

Answer:

Distancia = 925 metros.

Explanation:

Dados los siguientes datos;

Tiempo = 50 segundos

Velocidad = 18.5 m/s

Para encontrar la distancia recorrida;

Matemáticamente, la distancia viene dada por la fórmula;

Distancia = velocidad * tiempo

Sustituyendo en la fórmula, tenemos;

Distancia = 18.5 * 50

Distancia = 925 m.

Por tanto, el cuerpo recorrió una distancia de 925 metros.

7 0
3 years ago
Automotive air bags inflate when sodium azide decomposes explosively to its constituent elements:
andrezito [222]

Answer: 1.875 moles

Explanation:

2 NaN3(s) → 2 Na(s) + 3 N2(g)

From the equation above, Sodium azide has a chemical formula of NaN3 while nitrogen gas has a chemical formula of N2.

Therefore, If on decomposition

2 moles of NaN3 produce 3 moles of N2

1.25 mol of NaN3 produce Z moles of N2

To get the value of Z, cross multiply

Z x 2 moles = 3 moles x 1.25 moles

2 moles•Z = 3.75 moles²

Divide both sides by 2 moles

2 moles•Z/2 moles = 3.75 moles²/2 moles

Z = 1.875 moles

Thus, 1.875 moles of N2 are produced by the decomposition of 1.25 mol of sodium azide

3 0
4 years ago
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