The millions of fossils that scientists have collected are called the fossil __.

Answer:

The block is made up of aluminum.

density = 2.7 g/cm³

Explanation:

Given data:

Dimension of metal block = 2.0 cm×2.5 cm× 3.0 cm

Mass of block = 40.05 g

Density of block = ?

Which metal is this = ?

Solution:

Density:

Density is equal to the mass of substance divided by its volume.

The symbol used for density is called rho. It is represented by ρ. However letter D can also be used to represent the density.

Units:

SI unit of density is Kg/m3.

Other units are given below,

g/cm3, g/mL , kg/L

Formula:

D=m/v

D= density

m=mass

V=volume

Volume of block = 2.0 cm×2.5 cm× 3.0 cm = 15 cm³

d = m/v

d = 40.5 g/ 15 cm³

d = 2.7 g/cm³

The block is made up of aluminum.

Answer:

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\ [/tex]

So we have

[tex]density = \frac{25}{90} = \frac{5}{18} \\ = 0.277777...[/tex]

We have the final answer as

Hope this helps you

Answer:

Salt

Explanation:

It has all -

Answer:

Orange

Explanation:

I used google my b

Answer:

ORANGE

explanation:

Small pieces of sodium burn in air with often little more than an orange glow. Using larger amounts of sodium or burning it in oxygen gives a strong orange flame.

Answer:

Only about 1% of the freshwater on Earth is easily accessible.

Explanation:

Freshwater accounts for a minimal proportion of water resources on planet earth. About 70 percent of the world surface area  is covered by water, but only  about 2.5 percent of this mass of water is fresh. The remaining are marine or salt water. Amazingly, just about 1 percent of this  freshwater is easily accessible. The other 1.5% is trapped in glaciers and snowfields.

This underscore the need for water conservation on the planet since fresh water is a scarce resource and people living in many areas have no access to fresh water.

Answer:

1. Both metals and nonmetals are types of elements and can be involved in chemical reactions. Some of their differences are highlighted in the chart below.

  Metals:    

Appearance; Shiny.    

Conduct heat or electricity; Yes.  

Malleable or ductile; Yes, both and has great mechanical strength.    

Form stable compounds; Forms stable compounds with acids; also forms oxides; replaces hydrogen in acids or water; combine with nonmetals; often becomes positive.

  Nonmetals :  

Appearance; Not shiny .  

Conduct heat or electricity; Not well .  

Malleable or ductile; Brittle and not easily molded into shapes .  

Form stable compounds; Oxides usually give acid reactions in water; often becomes negative

2. The electrochemical series is an arrangement of metals in such order that any metal in the list is displaced from its compounds by any metal above it, but displaces any metal below it. The higher up the list a metal is, the greater its activity. Knowing a metal’s placement on this chart can help you understand the activity of the metal, especially in regard to its ability to displace hydrogen in acids. Any items on the list far above hydrogen will do a good job at displacing it, those near it won’t do such a good job, and those below it won’t displace it from acids at all.

3. When placed in water, acids dissociate and form free hydrogen ions, which determine the properties of acids. The number of hydrogen ions determines the strength of an acid. Strong acids dissociate to a large degree and produce a large number of hydrogen ions. Weak acids dissociate to only a slight degree.

When placed in water, bases dissociate and form free hydroxyl ions, which determine the properties of bases. Strong bases dissociate to a great degree and produce a large number of hydroxyl ions. Weak bases dissociate to only a slight degree.

When free hydrogen ions and free hydroxyl ions are removed from solutions of acids and bases, then the acidic and basic properties disappear. This is what happens when acids and bases are mixed together in proper proportion; the hydroxyl ion will unite with the hydrogen ion to form water. The resulting salt product is neutral.

4. Indicators are used to help determine the pH value of an unknown solution. These are often papers that turn a certain color at certain pH values.

Metals are good conductors of heat and electricity but the non-metals are not.

Metals are good conductors of electricity and heat whereas non-metals are poor conductors of heat and electricity. Metals have high density while on the other hand, non-metals have low density. Metals are malleable and ductile whereas non-metals are brittle.

So we can conclude that metals are good conductors of heat and electricity but the non-metals are not.

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Answer:

Na + CaSO4 = Na2SO4 + Ca

Explanation:

single displacement (substitution)

Answer:

P.E. = mgh, where m is the mass in kilograms,

Answer:

[tex]m = \frac{PE}{gh} [/tex]

Explanation:

[tex]if \: PE = mgh \\ then \to \\ m = \frac{PE}{gh} [/tex]

♨Rage♨

Answer:

34.611g

Explanation:

mass of metal = ?

density of metal = 1.39/cm³

volume = 24.9 cm³

density = mass/volume

mass = density × volume

= 1.39g/cm³ × 24.9 cm³

= 34.611g

The density of the wood : 1.45 g/cm³

Density is a quantity derived from the mass and volume  

Density is the ratio of mass per unit volume  

With the same mass, the volume of objects that have a high density will be smaller than objects with a smaller type of density  

The unit of density can be expressed in g/cm³ or kg/m³  

Density formula:  

[tex]\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}[/tex]

ρ = density  

m = mass  

v = volume  

[tex]\tt V=2.7\times 5.5\times 3.9=57.915~cm^3[/tex]

[tex]\tt \rho=\dfrac{m}{V}\\\\\rho=\dfrac{84~g}{57.915~cm^3}=\boxed{\bold{1.45`g/cm^3}}[/tex]

Answer:

easier and pollution

Explanation:

I just had this question and got it right

Answer:

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\ [/tex]

From the question

mass = 30.5 g

volume = 2.2 cm³

We have

[tex]density = \frac{30.5}{2.2} \\ = 13.863...[/tex]

We have the final answer as

Hope this helps you

Answer: Yes.

Explanation:

the number of protons in the nucleus determines an element's identity. Chemical changes do not affect the nucleus, so chemical changes cannot change one type of atom into another. The number of protons in a nucleus does change sometimes, however. The identity of the atom, therefore, changes.

Answer:

A. Potential energy is stored energy

Explanation:

Answer:

A

Explanation:

i have the same question

The speed of a wave can be calculated using this formula:

v = f x λ

Where:

v is the wave speed in metres per second, m/s

f is the frequency in hertz, Hz

λ (lambda) is the wavelength in metres, m

Calculation:

Given:

f = 20 Hz

λ = 100m

Using the equation:

v = f x λ

v = 20 x 100

v = 2000 m/s

Therfore, the speed of the wave is 2000 m/s

A sound wave has a wavelength of 100 m and a frequency of 20 Hz. The wave's speed is 2× 10^3 m/s.

assuming frequency = 20 Hz and wavelength = 100 m

utilized concept: v= = 20×100 = 2×10³ m/s

The frequency in physics is the quantity of waves passing a fixed location in a unit of time. It also indicates how many cycles or vibrations a body in periodic motion experiences in a given unit of time.

A sort of energy created by vibrations is sound. The molecules of the air surrounding an item vibrate as a result.. These molecules vibrate because they collide with nearby molecules, which also vibrate as a result.

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Answer:

the volume will expand

Explanation:

gas under pressure contracts, and expands with a lesser pressure

The volume of the hydrogen gas at 25 kPa is 8 Liters.

Explanation:

Given:

At constant temperature, 2 liters of hydrogen gas at 100kPa pressure.

To find:

The volume of the hydrogen gas at 25kPa.

Solution:

The initial pressure of the hydrogen gas =[tex]P_1=100 kPa[/tex]

The initial volume of the hydrogen gas at 100 kPa =[tex]V_1=2 L[/tex]

The final pressure of the hydrogen gas =[tex]P_2=25 kPa[/tex]

The final volume of the hydrogen gas at 25kPa = [tex]V_2=?[/tex]

Using Boyles law:

[tex]P_1V_1=P_2V_2\\100kPa\times 2 L=25 kPa\times V_2\\V_2=\frac{100 kPa\times 2L}{25 kPa}=8L[/tex]

The volume of the hydrogen gas at 25 kPa is 8 Liters.

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Answer:

true

Explanation:

please mark BRAINLIEST

Alkanes are saturated hydrocarbons that have single bonds in chains

General formula for alkanes :

[tex]\tt \large{\bold{C_nH_{2n+2}}[/tex]

Hydrocarbon combustion reactions (specifically alkanes)

[tex]\large {\box {\bold{C_nH _ (_2_n _ + _ 2_) + \dfrac {3n + 1} {2} O_2 \Rightarrow nCO_2 + (n + 1) H_2O}}}[/tex]

So that the burning of ethane with air (oxygen):

[tex]\tt C_2H_6+\dfrac{7}{2}O_2\rightarrow 2CO_2+3H_2O[/tex]

2C₂H₆ (g) + 7O₂ (g) ⟶ 4CO₂ (g) + 6H₂O (ℓ)

or we can use mathematical equations to solve equilibrium chemical equations by giving the coefficients for each compound involved in the reaction

C₂H₆ (g) + aO₂ (g) ⟶ bCO₂ (g) + cH₂O (ℓ)

C : left 2, right b ⇒ b=2

H: left 6, right 2c⇒ 2c=6⇒ c= 3

O : left 2a, right 2b+c⇒ 2a=2b+c⇒2a=2.2+3⇒2a=7⇒a=7/2

Answer:

boiling point

Explanation:

Option B

Answer:

the answer is water.Hope this helps

Answer:

V = 34.55 L

Explanation:

Given that,

No of moles, n = 1.4

Temperature, T = 20°C = 20 + 273 = 293 K

Pressure, P = 0.974 atm

We need to find the volume of the gas. It can be calculated using Ideal gas equation which is :

PV=nRT

R is gas constant, [tex]R=0.08206\ L-atm/mol-K[/tex]

Finding for V,

[tex]V=\dfrac{nRT}{P}\\\\V=\dfrac{1.4\times 0.08206\times 293}{0.974 }\\\\V=34.55\ L[/tex]

So, the volume of the gas is 34.55 L.

Answer:

i dont get the equation sorry wish i can help

Answer:carbon-14 levels in the atmosphere

Explanation:

When carrying out radiocarbon dating, the level of carbon-14 in a sample is compared with the level of carbon 14 in the atmosphere because, objects exchange carbon-14 with the atmosphere.

Comparison of the activities of carbon-14 in the atmosphere and in the sample gives the age of the sample since the half-life of carbon-14 is a constant.