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2 years ago

What’s the star made up of challenge?

Chemistry

1 answer:

Crank2 years ago

4 0

Answer:

Stars are made of very hot gas. This gas is mostly hydrogen and helium, which are the two lightest elements. Stars shine by burning hydrogen into helium in their cores, and later in their lives create heavier elements.Stars are huge celestial bodies made mostly of hydrogen and helium that produce light and heat from the churning nuclear forges inside their cores.

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Which of the following statements BEST describes a compound?

Oliga [24]

Answer:

A compond is made up of 2 or more elements that are both DIFFERENT so the answer is B.

Explanation:

8 0

3 years ago

J. Explain how an atom's valence electron configuration determines its place on the periodic table.

Darya [45]

Answer:

Elements having same valence electrons are placed in same group.

Explanation:

First, let's start with some basic concepts of modern periodic table:

1. Modern Periodic table : It is the arrangement of element in the increasing order of their atomic numbers

The Modern periodic table is divided into Periods and groups .

Periods : These are the horizontal rows. There are seven periods in the periodic table . Period 1 has 2 element. Period two and three has 8 elements , period 4 and 5 have 18 elements and the period 6 and 7 have 32 elements.

Same period have same number of atomic orbital(Shell)

Group : The group is the vertical columns . There are 18 groups in the modern periodic table.Those element which have same group number will also have same number of electron in their outermost shell. The number of electron in the outermost shell determines the valency of the element.

So, elements showing same valency are placed in same group.

All alkali are place in group 1 and have 1 valance electron in the outermost shell

5 0

4 years ago

What data do you need to determine the specific heat capacity of a substance?

strojnjashka [21]

Speific heat capacity is measured with the aid of determining how a whole lot warmth electricity is needed to increase one gram of a substance one digree Celsius. The Speific heat capacity of water is 4.2 joules per gram per degree Celsius or 1 calorie in step with gram per digree Celsius.

The specific heat capacity is defined as the amount of heat (J) absorbed consistent with unit mass (kg) of the substance while its temperature increases 1 ok (or 1 °C), and its units are J/(kg k) or J/(kg °C).

Factors specific heat capacity relate to are temperature and strength.

The Speific heat capacity C can be measured as q = mC∆T

Or, C = q/m∆T

where,

C is the specific heat capacity

q is the quantity of heat required

m is the mass

∆T is the change in temperature

As a consequence so as to degree the specific heat capacity we need to recognize mass of the substance, quantity of heat lost or gain by the substance and the exchange in temperature.

Lear more about Speific heat capacity here: brainly.com/question/17162473

#SPJ4

6 0

2 years ago

2.A calibration curve requires the preparation of a set of known concentrations of CV, which are usually prepared by dieting a s

Aleks04 [339]

Answer:

In order to prepare 10 mL, 5 μM; 2 mL of the 25 μM stock solution will be taken and diluted with water up to 10 mL mark.

In order to prepare 10 mL, 10 μM; 4 mL of the 25 μM stock solution will be taken and diluted up to 10 mL mark.

In order to prepare 10 mL, 15 μM; 6 mL of the 25 μM stock solution will be taken and diluted up to 10 mL mark.

In order to prepare 10 mL, 20 μM; 8 mL of the 25 μM stock solution will be taken and diluted up to 10 mL mark.

Explanation:

Using the dilution equation:

no of moles before dilution = no of moles after dilution.

Molarity x volume (initial)= Molarity x volume (final).

In order to prepare 10 mL, 5 μM from 25 μM solution,

Final molarity = 5 μM, final volume = 10 mL, initial molarity = 25 μM, initial volume = ?

25 x initial volume = 5 x 10

Initial volume = 50/25

= 2 mL

2 mL of the 25 μM stock solution will be taken and diluted up to 10 mL mark.

In order to prepare 10 mL, 10 μM from 25 μM stock,

25 x initial volume = 10 x 10

Initial volume = 100/25 = 4 mL

4 mL of the 25 μM stock solution will be taken and diluted up to 10 mL mark.

In order to prepare 10 mL, 15 μM from 25 μM stock,

25 x initial volume = 15 x 10

initial volume = 150/25 = 6 mL

6 mL of the 25 μM stock solution will be taken and diluted up to 10 mL mark.

In order to prepare 10 mL, 20 μM from 25 μM stock,

25 x initial volume = 20 x 10

initial volume = 200/25 = 8 mL

8 mL of the 25 μM stock solution will be taken and diluted up to 10 mL mark.

6 0

3 years ago

Is frictional force desirable?

gavmur [86]

Answer: Friction is a force that resists relative motion between two surfaces in contact. Depending on the application, friction may be desirable or undesirable.

6 0

3 years ago