which is a model that shows only the valence electrons of an atom?

To find the weight of the gold bar, we need to calculate its volume and use the density of gold. The gold bar weighs approximately 467.96 ounces.

To find the weight of the gold bar in ounces, we first need to calculate its volume in cubic inches and then convert it to cubic centimeters.

Given:

The volume (V) of a rectangular prism is given by V = Length x Width x Height.

V = 7.0 in x 3.0 in x 2.0 in = 42.0 in³

Since 1 inch is equal to 2.54 centimeters, we can convert the volume to cubic centimeters:

V = 42.0 in³ x (2.54 cm/in)³ = 686.98 cm³

Now, to find the weight of the gold bar in ounces, we can use the density of gold, which is 19.3 g/cm³.

The formula for density is Density = Mass/Volume.

Since we know the density and the volume, we can rearrange the formula to solve for the mass:

Mass = Density x Volume

Mass = 19.3 g/cm³ x 686.98 cm³ = 13,257.814 g

Finally, to convert the mass from grams to ounces, we divide by 28.35 grams/ounce:

Weight in ounces = 13,257.814 g / 28.35 g/oz = 467.96 oz

Therefore, the gold bar weighs approximately 467.96 ounces.

Plasma is the most energetic state of matter and primarily consists of ionized gases. Natural examples of plasma include stars like the Sun and phenomena like lightning, which ionize gases due to their high temperature and energy.

The question asks for an example of a plasma that occurs in nature. Plasma is the most energetic state of matter and is characterized by ionized gases made up of negatively charged free electrons and positively charged ions. In nature, stars such as the Sun are perfect examples of this. Stars, including the Sun, are so hot that the material they are composed of exists in the form of an ionized gas, or plasma. All particles in this state are rapidly in motion, continuously colliding with each other, leading to the pressure of the gas.

Not only stars, but certain weather phenomena such as lightning also contain plasma. The lightning's heat ionizes the gases in the atmosphere, leading to a plasma state. Therefore, the Sun and lightning are examples of plasma occurring naturally in the universe.

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This is a chemical change as the products have very different property as compared to reactant not only physically but also chemically. Therefore option c is correct option

Chemical change is a reaction in which breaking and forming of new bonds take place. One molecule completely converted to totally different molecule. The number of atoms remains same

One famous example of chemical change is the rusting of iron. In our case tip of match is ignited  as it is struck against the matchbox, so here combustion reaction is taking place, Red phosphorous is burning in presence of oxygen. The color, odor and arrangements of atoms in products are very much different from reactant.

Therefore, the tip of the match is flammable and is set on fire is the correct one . The correct option is option C

Learn more about the chemical change, here:

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warm air rises and takes heat with it

Answer: The correct answer is Option B.

Explanation:

There are 3 subatomic particles present in an atom. They are: protons, electrons and neutrons.

Any neutral atom has equal number of protons and electrons.

Hence, the correct answer is Option B.

If your answer choices are:

It stays the same.

It doubles.

It triples.

It is reduced.

The correct answer is "It stays the same."

To extract 50.0 g of nickel from an ore that is 26.9% nickel by mass, you would need approximately 0.1859 kilograms of the ore.

To calculate the amount of ore needed to obtain 50.0 g of nickel, we use the percentage of nickel in the ore and set up a simple proportion.

Firstly, we know that the ore is 26.9% nickel by mass. This means that for every 100 g of ore, there are 26.9 g of nickel.

To get 50.0 g of nickel, we can set up the equation (26.9/100) × mass of ore = 50.0 g.

By rearranging the equation for the mass of the ore, we get the mass of the ore = (50.0 g) / (26.9/100).

Calculating the mass of the ore, we find it to be approximately 185.9 g, which we can then convert to kilograms.

To convert grams to kilograms, we divide by 1000. So, 185.9 g is equivalent to 0.1859 kg.

Therefore, to obtain 50.0 g of nickel, approximately 0.1859 kilograms of ore is required.

Answer:

Explanation:

A double repalcement reaction is a type of reaction in which there is exchange of ions between two compounds leading to the formation of new products. It is also known as double displacement reaction.

BC+DE produces BE+CD.

A double replacement reaction leads to the formation of two new compounds Be and CD.

Answer:

c

Explanation:

Goods are objects that fulfill peoples needs and wants.

Vacuum filtration is a separation technique that is used to separate a solid product from a liquid. The method involves pouring the mixture of the solid and the liquid through a filter paper that is inserted inside a funnel. The filter paper trap the solid while the liquid is drawn through the funnel into the flask by a vacuum. It is very important to ensure that there is no gap around the edges of filter paper that is inserted into the funnel so that the mixture will not escape the filter paper and be poured directly into the flask below, thus messing up the separation process.