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3 years ago

Help me pretty please

Chemistry

1 answer:

drek231 [11]3 years ago

5 0

Answer:

Light demonstrates wave-like and particle-like characteristics

Explanation:

Light itself is a wave but under circumstance it will present particle-like charcteristics. This is called wave-particle duality :)

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A square chunk of plastic has a length of 5 cm, width of 5 cm and height of 5 cm. It has a mass of 200 g. What is it’s density

vichka [17]

Answer:

1.6g/mL

Explanation:

Density equation is D=m/v

Density = g/mL

m=mass of sample in grams

v = volume of sample in mL

The volume of a square can be calculated by V=l*w*h.

In this case it is 5cm*5cm*5cm = 125cm^3

Since we know that 1cm^3 ~ 1mL we can convert the volume to mL as so:

125cm^3 (1mL/(1cm^3)) = 125mL

Then simply plug into the density equation:

D=200g/125mL = 1.6g/mL

3 0

3 years ago

The image shows the representation of an unknown element in the periodic table. A square is shown. Inside the square twelve is w

Ludmilka [50]

Answer: The correct answer is the mass number of the most common isotope of the element is 24.

Explanation:

We are given:

An element having atomic number 12 is magnesium and atomic mass of the element is 24.305

The image corresponding will be $_{24.305}\textrm{Mg}^{12}\\\text{Magnesium}$

The number '24.305' is the average atomic mass of magnesium element.

Average atomic mass is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.

Formula used to calculate average atomic mass follows:

$\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i$

Average atomic mass of magnesium = 24.305 amu

As, the average atomic mass of magnesium lies closer to the mass of Mg-24 isotope. This means that the relative abundance of this isotope is the highest of all the other isotopes.

The 'Mg-24' isotope is the most common isotope of the given element.

Hence, the correct answer is the mass number of the most common isotope of the element is 24.

4 0

3 years ago

With a force of 5 newtons, Amanda pushes the stack of books to the right. At the same time, Jeremy, her little brother, pushes t

Allisa [31]

Answer:

A. 5 N to the left

Note: The question is incomplete. The complete question is given below:

With a force of 5 newtons, Amanda pushes the stack of books to the right. At the same time, Jeremy, her little brother, pushes the stack of books to the left with a force of 10 newtons.

What is the direction and magnitude of the resulting force?

A. 5 N to the left

B. 5 N to the right

C. 10 N to the right

D. 10 N to the left

Explanation:

Forces are vector quantities.

Vector quantities are quantities that can be represented both in magnitude and direction.

Forces have both magnitude and direction. Forces can be directed positively or negatively.

For example, in the question above, if forces acting to the right are considered to be in the positive direction, forces acting to the left are considered to be acting in a negative direction.

In the addition of forces, both their magnitude and direction are taken into consideration.

In the example above, taking forces acting to the right as positive and to the left as negative, the sum of the forces is:

Resultant force, F = (5 N) + (-10N)

F = -5 N

Therefore, the net force is 5 N and is directed towards the left

5 0

3 years ago

Read 2 more answers

1. Which of the following is a correctly written thermochemical equation?

WITCHER [35]

Explanation:

1. Thermochemical equation is balance stoichiometric chemical equation written with the phases of the reactants and products in the brackets along with the enthalpy change of the reaction.

The given correct thermochemical reactions are:

$Fe(s)+O_2(g)\rightarrow Fe_2O_3(s),\Delta H = 3,926 kJ
$

$C_3H_8(g)+5O_2 (g)\rightarrow 3CO_2 (g)+4H_2O(l),\Delta H= 2,220 kJ/mol$

2. Phase change affect the value of the enthalpy change of the thermochemical equation. This is because change in phase is accompanied by change in energy. For example:

$H_2O(s)\rightarrow H_2O(g),\Delta H_{s}=51.1 kJ/mol$

$H_2O(l)\rightarrow H_2O(g),\Delta H_{v}=40.65 kJ/mol$

In both reaction phase of water is changing with change in energy of enthalpy of reaction.

7 0

3 years ago

Read 2 more answers

How many moles are there in 7.5 L Of H2

True [87]

So multiply number of moles x number of atoms/mole = 1.8066 x 10^24 atoms of H2. One mole of any gas at STP has a volume of 22.4 L. So first determine the number of moles of gas you have.
for example do 7
$7.5 \div 22.4$
that 's what I think

3 0

3 years ago