Hi! Please help me!

Which of the following is the combination of 2 elements? Explain.
a) Si b) CO c) He d) Fe

Answer:

Oxygen is in group 16 in the periodic table.  All the elements in this group have in common the number of valence electrons in their outer shell (6 valence electrons).  The only reason I can see that they may be considered "mixed"  is because the group includes non metals and metalloids.

Explanation:

Chemical reactions must consists of reactants and products.

A chemical reaction is said to occur when two or more substances interact and lead to the formation of a new substance. Another name for a chemical reaction is chemical change.

Now consider the reaction;

HCl(aq) + NH3(g) -----> NH4Cl(aq)

HCl(aq) + NaOH(aq) ---->  NaCl(aq) + H2O(l)

CaCO3 + 2HCl(aq) -----> CaCl2(aq) + CO2(g) + H2O(l)

Learn more about chemical reaction: https://brainly.com/question/6876669

Answer:

Metamorphic Rock

Explanation:

Metamorphic rocks are formed because of high heat and pressure . Metamorphic rocks form from heat and pressure changing the original or parent rock into a completely new rock. The parent rock can be either sedimentary, igneous, or even another metamorphic rock

Answer:

answer is metamorphic.......

Answer:

All of the above

Explanation:

I believe all three are true. They see how the organism is similar to other organisms. They see if the organism has the characteristics of an animal or plant. They look at what makes the organism unique.

Answer: 2

Explanation:

Answer:

In the United States alone, the AKC's dog breed list currently includes 190 dog breeds. Worldwide, the FCI lists 360 officially recognized breeds.

Explanation:

Answer:

Central and South American forests.

Explanation: https://brainly.in/question/7540305

Answer:

High luster- shiny: metals

Low luster- dull: non-metals

Is Ductile- can be pulled into thin wires: metals

Not ductile: non-metals

Not malleable- is brittle: non-metals

Is malleable- elements can be hammered into thin sheets: metals

Poor conductors of heat and electricity: non-metals

Good conductors of heat and electricity: metals

Located on the left side of the periodic table: metals

Located on the right side of the periodic table: non-metals

sorry if i got something wrong but i think this is all right

hope this helps :)

Answer:

High luster shiny is the characteristic of metals while low luster and dull is a non metal.

Metals are ductile because wires are made up of metals which is due to their ductility. non metals are not ductile.

Non metals are non melliable while metals are melliable

Non metals are poor conductor while metals are good conductor of heat and electricity.

Metals are located on the left side while non metals are located on right side of periodic table.

Explanation:

Answer: D) longer wavelength.

Explanation:

Answer:

There could be several possible reasons for a small gap between rails on a railway track, such as:

1. Expansion joints: Railways are designed to allow the tracks to expand and contract with changes in temperature. To accommodate this expansion, small gaps are left between the rail ends and filled with expansion joints or plates.

2. Wear and tear: Over time, the rails may experience wear and tear due to heavy loads, weather conditions, and other factors. As a result, small gaps can appear between the rails.

3. Maintenance: During maintenance activities, rail tracks may be adjusted or replaced, which could lead to small gaps between the rails.

4. Environmental factors: Environmental factors such as soil shifts, earthquakes or other natural disasters can also affect the alignment of the rails, leading to small gaps.

These are some of the possible reasons for a small gap between the rails on a railway track.

Answer:

The small gap left between the rails in a railway track is intentional and serves a specific purpose. This gap is known as the rail joint, and it allows for the expansion and contraction of the rails due to changes in temperature. When the temperature changes, the metal rails will expand or contract, and if they were joined together tightly, they could buckle or become deformed, which could be dangerous for trains passing over them. The rail joint allows the rails to move slightly and prevent damage to the track.

Additionally, the rail joint also allows for maintenance and repairs of the track. If there were no gap between the rails, it would be challenging to replace a damaged rail or perform routine maintenance, such as tightening bolts or lubricating joints. With the rail joint, maintenance personnel can easily access and work on the track.

Overall, the small gap left between the rails in a railway track is intentional and serves a crucial function in ensuring the safety and reliability of the track.

Answer:

a

Explanation:

just needed the points, sorry

Answer:

I'm confused what is this?

Explanation:

Answer:

In carbon cycle, carbondioxide gas is present in the atmosphere. This carbondioxide gas is taken inside by the plant body through stomata and made food from it. When this food is eaten by animals, this carbon is transferred to their bodies. During breathing, carbondioxide gas is removed from animal body and the carbondioxide gas again goes to the atmosphere.

Explanation:

Answer:

The carbon cycle is similar to the water cycle!

Explanation:

The water cycle shows us that water on Earth isn't destroyed or created, it simply moves around in different forms. Carbon is like that too, but except becoming droplets and clouds it passes through stages where it can exist in the ground as things like coal and be burnt where it will then move into the atmosphere as a gas, until eventually that gas is used to grow a plant. Eventually, that plant will be eaten by an animal, and when that animal dies it goes into the ground once again. Hence, the carbon is always there, just going throughout the planet in different forms.

Answer:

Some small volcanoes only erupt once in their lives,

while other volcanoes erupt multiple times. Kilaeua volcano in Hawaii, which has been erupting continuously since 1983, is the world's most active volcano. While some volcanoes erupt at regular intervals, there are always exceptions to the rule

Answer:

small volcano's only 1 time while big volcano's mutiple times

Explanation:

Answer: The answer is A. Halogens

Explanation:

I hope this helps you :)

Answer:

Explanation: Two in reactants and two in products.

Answer:

THANK YOU

YOU TOO!

Explanation:

thank you

so much i hope you have a great day aswell

Answer:

B

Explanation:

Answer:

c

Explanation:

While standing water in the streets and sewers (option A) and poor water quality in rivers and streams (option D) may persist for some time after the flood, they are generally considered short-term changes as they can eventually be remedied through clean-up efforts and restoration programs.

Temporary displacement of organisms (option B) can also be considered a short-term change, as organisms will eventually return to their original habitats once conditions improve.

However, a permanent change in the landscape (option C) such as altered river channels, new water bodies, or changes in topography, can have lasting effects on the ecosystem and its inhabitants. These changes may alter habitat suitability, nutrient cycling, and water availability, which can impact the ecosystem for years or even decades to come.

Answer: C

Explanation:

The landscape could be flooded. Houses and buildings may be restricted.

Answer:

It is the mechanical clock, and according to many historians, it was the clock that changed everything and deserves to be called as the key factor of the industrial age. Mechanical clocks enabled people to measure time in ways that were not possible before, and because of it, our lives were changed forever.

Explanation:

Answer:

It is the mechanical clock, and according to many historians, it was the clock that changed everything and deserves to be called as the key factor of the industrial age. Mechanical clocks enabled people to measure time in ways that were not possible before, and because of it, our lives were changed forever.

Explanation:

opppsss we said the same thing sry

Answer:

I think people now are more carefull with trash they throw on the ground and stuff because there more aware of what trashing the earth can do. These days, we have more scientific research on our planet and more people care then back then in 1970, there wasn't a law on littering or on saving the planet, so definetly people are better at keeping the earth clean now days.

Explanation:

Answer:

Electrical resistance is a measure of resistance to the flow of electric current.

I Hope This Helps!

Answer:

I think b is the correct answer

Explanation:

Answer:I think maybe C? I don’t know... I am in 6th grade and I don’t know what grade science this is...

Explanation:

Answer:

Reactants contact each other, bonds between atoms in the reactants are broken, and atoms rearrange and form new bonds to make the products.RT

Explanation:

Answer:

Explanation:

Leaves changing color is a chemical change because it involves a transformation of the chemical composition of the pigments within the leaves. During this process, the green pigment chlorophyll breaks down, revealing other pigments such as carotenoids (which produce yellow, orange, and brown colors) and anthocyanins (which produce red and purple colors). These pigments undergo chemical reactions that change their molecular structures, resulting in new colors.

In a physical change, the substance itself remains the same, but its physical properties may change, such as its shape, size, or state (solid, liquid, gas). However, in the case of leaves changing color, the chemical composition of the pigments is altered, resulting in a new substance with different properties. Therefore, this process is considered a chemical change.

Answer:

Why would leaves changing color be a chemical change and not a physical change?

Well, a chemical change is when a new substance IS formed and a physical change is a type of change in which a new substance is NOT formed. So leaves changing color would be a chemical change because they involve chemical reactions to occur.

Explanation:

You're welcome

Answer:

+6.

Explanation:

So, a chromium atom here has an oxidation number of +6.

Answer:

1. Planets; movement of planets around the sun and other stars in the galaxy is kinetic energy

2. Rubber Bands; can be classified as both potential and kinetic energy, depending on the state of the band (when stretch=potential energy; when released=kinetic energy)

3. Rivers; strictly kinetic energy. the water is constantly moving creating kinetic energy.

Explanation:

Answer:

. a reference point is required to determine whether or not an object moves

Explanation:

Answer:I would say gravity, The way the object is shaped..? You'll also need a reference point to figure out if the object is moving or not. I hope I helped! <3

Explanation: