I need help on these two questions please!!!

Answer:

A.'C

Explanation:

Please answer my question

Answer:

the answer would be a

Explanation:

Answer:

Explanation:

The last number in a measured number is always an estimated digit.

Answer:

Presence of impurities in the product.

Explanation:

Laboratory experience has shown that the percent yield obtained from a reaction may be greater than 100% if the product obtained from the reaction contains impurities that causes its mass to be greater than it actually would be if the product was pure.

A typical impurity that may be present in a product is the solvent used. This can be removed by evaporation of the solvent or by washing the product thoroughly.

Reaction of solid products with gases may also increase the percentage yield above 100%.

Answer:

2.6 g

Explanation:

Percent concentration = 5%

Volume of water = 50ml

Since 1ml of water = 1g of water

Mass of water= 50g

Let the mass of sucrose be x

Mass% = mass of solute/mass of solute + mass of solvent × 100

5= x/x+ 50 ×100

5/100 = x/x + 50

0.05 = x/x + 50

0.05(x + 50) = x

0.05x + 2.5 = x

2.5 = x - 0.05x

2.5 = 0.95x

x= 2.5/0.95

x=2.6 g

Answer:

The mass of  Mg  and the mass of  Cl  in the sample

Explanation:

We have that the sample's is purity is simply the mass of Mg and the mass of Cl in the sample

From the Question we are told that

Mass of MgCl2 =5g

Therefore

What we need to  determine that the sample's is purity is simply the mass of Mg and the mass of Cl in the sample because

the mass of MgCl should be equal to mass of Mg and mas of Cl

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Answer:

A. 2 protons, 2 electrons, and 1 neutron .

Answer:

A 2 protons, 2electrons,1 neutron

Answer:

It was just on a way and scienticts cant really "delete" it from galaxy so they descided accepting it and study it.

Explanation:

Answer:

In 1543 he further developed the heliocentric model. Copernicus was able to work out the arrangement of the known planets and how they move around the sun.

Explanation:

hope this helps:)

Answer:

28.705 cm

Explanation:

Hello,

In this case, for rounding the number to five significant figures we must "cut" it at 5 so we hide the 3, therefore it turns out:

28.705 cm.

Moreover, we must realize that since such 3 is less than five, we do not modify the previous five to six, case which would happen if that three has changed to five or more.

Regards.

Answer: 65%

Explanation:

When in probability and the outcome is mutually exclusive which means that either one or the other will happen then the probabilities of the events should be added up.

P(A or B) = P(A) + P(B)

P(Rain or Hail) = P(Rain) + P(Hail)

P(Rain or Hail) = 30% + 35%

P(Rain or Hail) = 65%

Answer:

ΔH = 87.8kJ

Explanation:

You can determine ΔH of a reaction from the sum of similar reactions (Hess's law). In the problem with the given ΔH:

1. C5H12(l)+8O2(g)→ 5CO2(g)+6H2O(g) ΔH= -3505.8 kJ

2. C(s)+O2(g)→CO2(g) ΔH= -393.5 kJ

3. 2H2(g)+O2(g)→ 2H2O(g) ΔH= -483.5 kJ

5 times 2. + 3 times 3:

5C(s) + 8O2(g) + 6H2(g) → 5CO2(g) + 6H2O(g)  

ΔH= 5*(-393.5 kJ) +  3*(-483.5 kJ) = -3418kJ

Now, this reaction - 1:

5C(s)+6H2(g) → C5H12(l) ΔH= -3418kJ - (-3505.8kJ)

Answer:

B

Explanation:

Explanation:

You are suppose to use sig figs.

Answer: 0.05

Explanation:Divide the length (1.5 cm) by the number of turns (30)

The direct proportion rule allows you to find that the correct answer for the result of the thickness of the copper wire is:

            0.05 cm

Copper is a strong material with which the cross section is constant, therefore the copper wire has a constant thickness, which is why when making a full turn it advances the same amount

When Jade wound thirty times (n = 30) it has the same diameter each time, therefore with a direct rule of proportions we can find the thickness of the wire.

If in 30 laps we have 1.5 cm, in one lap we have?

            [tex]x= 1 turn ( \frac{1.5 cm}{30 turn} )[/tex]  

            x = 0.05 cm

In conclusion using a direct rule of proportions we can that the correct answer for the result of the thickness of the copper wire is:

             0.05 cm

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Answer:

the density increases

Explanation:

Coz high temperature makes water less dense. As water gets warmer, its molecules spread out, so it becomes less dense. As it gets colder, it becomes denser

The heat from the oven heats up the metal pan, and the metal pan transfers the heat to the brownies.

Heat conduction is defined as the transfer of heat in an object from the area of hotter region to the area of cooler region through microscopic particles and movement of electrons within the body.

All the objects such as metal brownie pan that is capable of conducting heat is called the term thermal conductivity.

Examples of metals that are good conductors of heat include the following Gold, Silver, Copper, Aluminium, Iron.

Therefore, is can be concluded that the oven heats up the metal pan, and the metal pan transfers the heat to the brownies.

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Answer:

2.33×10¯¹⁶ g of forsterite

Explanation:

From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ atoms. This equally means that 1 mole of forsterite (Mg2SiO4) contains 6.02×10²³ atoms.

1 mole of forsterite (Mg2SiO4) = (24×2) + 28 + (16×4)

= 48 + 28 + 64

= 140 g

Finally, we shall determine the mass of forsterite that contains a million oxygen atoms.

140 g of forsterite (Mg2SiO4) contains 6.02×10²³ atoms.

Therefore, Xg of forsterite (Mg2SiO4) will contain 1×10⁶ atoms of oxygen i.e

Xg of forsterite (Mg2SiO4) =

(140 × 1×10⁶) /6.02×10²³

= 2.33×10¯¹⁶ g

Therefore, 2.33×10¯¹⁶ g of forsterite contains a million oxygen atoms..

The  mass of forsterite that contains a million oxygen atoms is 5.67 × 10^-17 g.

The chemical formula of forsterite is Mg2SiO4. Now, molar mass of forsterite is; 2(24) + 28 + 4(16) = 140 g/mol

Next, we have to obtain the number of oxygen atoms that are found in 1 mole of forsterite  as follows;

Number of oxygen atoms in 1 mole = 1 × 4 × 6.02 × 10^23 = 24.08  × 10^23 atoms

Now;

If 1 mole of forsterite  contains 24.08  × 10^23 atoms oxygen atoms

x moles of  forsterite  contains 1 × `10^6 atoms

x =  1 mole × 1 × `10^6 atoms/24.08  × 10^23 atoms

x = 4 × 10^-19 moles

Mass of forsterite that  contains  a million oxygen atoms = 4 × 10^-19 moles

×  140 g/mol = 5.67 × 10^-17 g

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Answer:

For 1 hour 75w light bulb requires 270 kj  for burning

for 3 hours 75 w light bulb requires 270*3 = 810kj for burning

Explanation:

Answer:

Protons: 26

Neutrons: 30

Explanation:

Explanation:

Each carbon atom is covalently bonded to four other carbon atoms in diamond. A lot of energy is needed to separate the atoms. This is because covalent bonds are strong. This is the reason why diamond has a high melting point.

Answer:

d. I and II only

Explanation:

Evaporation is the breakaway of liquid molecules through the surface of a liquid, into the surrounding atmosphere in the form of a gas. Evaporation increases with temperature, since the molecules posses more kinetic energy to break through the liquid surface barrier at a higher temperature. Also, an increase in the surface area puts more of the molecules of the liquid close to the interface of the liquid and the surrounding atmosphere, increasing their chances of breaking away. An increase in the intermolecular forces between the molecules of the liquid will only decrease the rate of evaporation, since more energy will be required by the liquid molecules to break free from the bond between them and their neighboring molecules.

Answer: She needs to divide the mass by the volume to find the density of the object.

Explanation:

Answer:

4320 inches

Explanation:

math

A football field is supposed to be exactly 120yd long, including the end zones is 4320 inches.

Zones are defined as a space that is physically or artificially isolated from other spaces. There are numerous sorts and sizes of zones.

Zones are also defined as a region that is designated as having a specific average annual minimum temperature, which is important for many plants to survive.

There are four types of zones.

The Torrid Zone, Temperate Zone, and Frigid Zone are the three temperature-based regions of the Earth.

Planting zones are predetermined areas based on the types of plants that thrive there.

Thus, a football field is supposed to be exactly 120yd long, including the end zones is 4320 inches.

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Answer:

No because the sugar that went to it dissolved and the fruits are very blended in. It depends what smoothie it is because you can evaporate a strawberry smoothie and have only the strawberry mix instead of the water or milk.

Explanation:

Answer:

Calculate the unknown variable in the equation for gravitational potential energy, where potential energy is equal to mass multiplied by gravity and height; PE = mgh. Calculate for different gravity of different enviornments - Earth, the Moon, Jupiter, or specify your own. Free online physics calculators, mechanics, energy, calculators.

Explanation:

Answer: Sí

Explanation: ya que una mascota es inofensiva, pero para fotografiar a un animal salvaje, debes esperar pacientemente el momento perfecto

Answer:

See explanation

Explanation:

In this question, we have to remember that in all combustion reactions we will have Oxygen as reactive ([tex]O_2[/tex]) and the products are Carbon dioxide ([tex]CO_2[/tex]) and Water ([tex]H_2O[/tex]). Additionally, for the states, we will have (l) for the liquid state and (g) for the gas state. So, we can analyze each reaction:

Part A.

The formula for nonane is [tex]C_9H_2_0[/tex], with this in mind we can write the combustion reaction:

[tex]C_9H_2_0_(_I_)~ +~ O_2~->~CO_2_(_g_)~ +~H_2O_(_g_) [/tex]

When we balance the reaction we will obtain:

[tex]C_9H_2_0_(_I_)~ +~14 O_2_(_g_)~->~9CO_2_(_g_)~ +~10H_2O_(_g_) [/tex]

Part B.

The formula for 2-methylbutane is [tex]C_5H_1_2[/tex], with this in mind we can write the combustion reaction:

[tex]C5H12_(_I_)~ +~O_2_(_g_)~->~CO_2_(_g_)~ +~H2O_(_g_) [/tex]

When we balance the reaction we will obtain:

[tex]C5H12_(_I_)~ +~8O_2_(_g_)~->~5 CO_2_(_g_)~ +~6 H2O_(_g_) [/tex]

Part C.

The formula for 3-ethyltoluene is [tex]C_9H_1_2[/tex], with this in mind we can write the combustion reaction:

[tex]C_9H_1_2_(_I_)~+~O_2_(_g_)~->~CO_2_(_g_)~+~H2O_(_g_)[/tex]

When we balance the reaction we will obtain:

[tex]C9H12_(_I_)~ +~12O_2_(_g_)~->~9CO_2_(_g_)~ +~6H2O_(_g_)[/tex]

See figure 1 for further explanations.

I hope it helps!

Answer:

B) The molecular orbital formed is lower in energy than a hydrogen 1s atomic orbital.

Explanation:

When two atoms of hydrogen come close to each other , there is formation of molecular orbital . Due to overlap of 1 s orbital of one and 1 s orbital of another atom , two molecular orbitals are formed . One of these molecular orbital has energy less than 1 s atomic orbital . It is called 1 s sigma bonding molecular orbital . The other molecular orbital has energy more than 1 s atomic orbital . It is called antibonding molecular orbital . Two electrons occupy bonding sigma molecular orbital .

So , the statement that "the molecular orbital formed is lower in energy than a hydrogen 1s atomic orbital " is wrong .