I'm having trouble with this one​

Answer:

In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed. The distinction between physical and chemical change is not clear cut.

Answer:

The number of outermost energy level electrons ( valency electrons )

The atomic number

Answer:

an

Explanation:

It is AN because investigation starts with I ( i is a vowel). When there are vowels we use An.

Pls mark me brainliest!

Answer:

The products from the neutralization reaction are barium nitrate and water.  

The balanced chemical equation is

2 [tex]HNO_{3}[/tex] +  1 [tex]Ba(OH)_{2}[/tex]  -->  1 [tex]Ba(NO_3)_{2}[/tex] +  2 [tex]H_{2}O[/tex].  

Answer:

Copper oxide + magnesium = copper + magnesium oxide

Explanation:

When copper oxide is heated with magnesium powder, then magnesium oxide and copper are formed.. For example, magnesium is more reactive than copper. ... brown copper coats the surface of the magnesium.

Answer:

strong nuclear forces that hold them together

Answer:

wla dyan ang sagut ehh baka mali yan

Answer: 55.7 moles of [tex]H_2O[/tex] are needed to produce the given amount of [tex]H_2[/tex]

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass.

The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given values:

Moles of [tex]H_2[/tex] = 55.7 moles

The chemical equation for the decomposition of water follows:

[tex]2H_2O\rightarrow 2H_2+O_2[/tex]

By the stoichiometry of the reaction:

If 2 moles of hydrogen gas is produced from 2 moles of water

So, 55.7 moles of hydrogen gas will be produced by = [tex]\frac{2}{2}\times 55.7=55.7mol[/tex] of water

Hence, 55.7 moles of [tex]H_2O[/tex] are needed to produce the given amount of [tex]H_2[/tex]

Taking into account the reaction stoichiometry,

In first place, the balanced reaction is:

2 H₂O → 2 H₂ + O₂

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

The following rule of three can be applied: if by reaction stoichiometry 2 moles of H₂ are produced from 2 moles of H₂O, 55.7 moles of H₂ are produced from how many moles of H₂O?

[tex]moles of H_{2} O=\frac{55.7 moles of H_{2}x 2 moles of H_{2} O}{2 moles of H_{2}}[/tex]

moles of H₂O= 55.7 moles

Finally, 55.7 moles of H₂O is requiredto produce 55.7 moles of H₂.

Learn more about the reaction stoichiometry:

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Answer:

6.5 moles of Oxygen are required

Explanation:

Based on the reaction:

CH3OH + 1/2 O2 → CH2O + H2O

1 mole of methanol reacts with 1/2 moles O2 to produce 1 mole of formaldehyde and 1 mole of water.

Thus, to produe 13 moles of formaldehyde, CH2O, are needed:

13 moles CH2O * (1/2mol O2 / 1mol CH2O) =

Answer: The statement, carbon has the ability to bond with up to six other atoms is false.

Explanation:

Carbon is a group 14 element and it is a non-metal. The atomic number of carbon is 6 and its electronic distribution is 2, 4.

This means that there are 4 valence electrons present in it. Also, in order to attain stability a carbon atom forms only covalent bonds, that is, it shares its valence electrons with its own atoms or atoms of other elements.

Carbon has the capacity to form single and double bonds.

As valency of carbon is four so it can only combine to 4 other atoms vis single bond and it cannot bond with up to six other atoms.

Carbon shows the property of catenation, that is, it forms covalent bonds with its own atoms in a large number. So, carbon has the ability to bond together to form extensive branched or unbranched "carbon skeletons".

Thus, we can conclude that the statement, carbon has the ability to bond with up to six other atoms is false.

Explanation:

u can put them in order crossed are spectator ions. hope this helps:)

endothermic

requires energy to occure

Answer:

-3169

Explanation:

trust the process

-3169 kJ/mol is the enthalpy of combustion when 1 mol [tex]C_6H_6(g)[/tex] completely reacts with oxygen.

Explanation:

Given:

The reaction of combustion of [tex]C_6H_6(g)[/tex] along with enthalpies of formation of the compounds.

To find:

The enthalpy of combustion when 1 mol [tex]C_6H_6(g)[/tex]  completely reacts with oxygen.

Solution:

[tex]2C_6H_6(g) + 15O_2(g) \rightarrow 12CO_2(g) + 6H_2O(g)[/tex]

Enthalpy of the reaction:

[tex]\Delta H^o_{rxn}=\sum [\Delta H^o_{f,products}]-\sum [\Delta H^o_{f,reactants}]\\=[12mol\times \Delta H^o_{f.CO_2(g)}+6mol\times \Delta H^o_{f,H_2O(g)}]-[2 mol\times \Delta H^o_{f.C_6H_6(g)}+15\times \Delta H^o_{f,O_2(g)}]\\=[12mol\times (-393.50 kJ/mol)+6mol\times (-241.82 kJ/mol)]-[2mol\times 82.90kJ/mol+15mol\times 0 kJ/mol]\\=-6338.72 kJ[/tex]

[tex]2C_6H_6(g) + 15O_2(g) \rightarrow 12CO_2(g) + 6H_2O(g).\Delta H^o_{rxn}=-6338.72 kJ[/tex]

When 1 mole of [tex]C_6H_6(g)[/tex]  reacts with oxygen gas:

[tex]=\frac{\Delta H^o_{rxn}}{\text{2 mol of } C_6H_6}\\=\frac{-6338.72 kJ}{2 mol}\\=-3169.36 kJ/mol\approx -3169 kJ/mol[/tex]

-3169 kJ/mol is the enthalpy of combustion when 1 mol [tex]C_6H_6(g)[/tex] completely reacts with oxygen.

Learn more about enthalpy of combustion here:

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H₂ + ½O₂ → H₂O

2g → 18g

So, 18g water needs 2g H₂

So, 1g water needs 2/18g H₂

So, 180g water needs 2/18 x 180g H₂

→ 20 litres of H₂

Answer:

Explanation:

Molar mass of water, H2O = 2 + 16 = 18

So 180g of water contains 10M

H2 + O -> H2O

10M of Hydrogen is needed to produce 10M of water.

Molar volume at STP = 22.4L

So 10M of Hydrogen at STP = 224L

With Ideal Gas Law, P1V1/T1 = P2V2/T2

At STP, P1 = 1atm, T1=273K

At 0.97atm and 24c (273+24 = 297K), 10M of Hydrogen will take up:

1*224/273 = 0.97*V2/297

V2 = 224*297/273/0.97

= 251.23L

So the answer is 251.23L

Answer:

Plants ➯ Mouse ➯ Snake ➯ Hawk ➯ Sun

Explanation:

In Order As A Food Chain

The elements are arranged into food chain like plants ⇒Mouse ⇒ Snake⇒ Hawk ⇒ Sun.

A substance that could not be further decomposed according to any chemical reaction is known as a chemical element.

The flow of nutrients as well as energy through such an ecosystem is described by a food chain. Energy is first produced by plants at the most fundamental level, and then it is used by higher-level species like herbivores. Energy is then transmitted from one carnivore to the next when they eat the herbivores.

The elements are arranged into food chain like plants ⇒Mouse ⇒ Snake⇒ Hawk ⇒ Sun.

To know more about food chain and element

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Answer:

The air that is inside a ship is much less dense than water. That's what keeps it floating

Answer:

The periodic table has rows that go left to right and columns that go up and down, just like any other grid. The rows are referred to as PERIODS, while the columns are referred to as GROUPS.

Explanation:

The periodic table was invented by Russian chemist Dmitri Mendeleev in 1869.

Answer:

B. Dmitri Mendeleev

Explanation:

Answer:

A. Sodium (Na)

Explanation:

The total number of electrons in the outermost principal energy level of an element is called the valence electrons of that element.

Na (11)---→1s2 2s2 2p6 3s1

There 1 electron in the outermost principal energy level of Sodium. So, the number of valence electron of Sodium is 11.

Answer:

Na

Explanation:

I was learning about it recently, that dude's right, it's Sodium

Answer: There are [tex]2.032 \times 10^{25}[/tex] molecules [tex]S_{2}[/tex] gas are in 756.2 L.

Explanation:

It is known that 1 mole of any gas equals 22.4 L at STP. Hence, number of  moles present in 756.2 L are calculated as follows.

[tex]Mole = \frac{Volume}{22.4 L}\\= \frac{756.2 L}{22.4 L}\\= 33.76 mol[/tex]

According to mole concept, 1 mole of every substance contains [tex]6.022 \times 10^{23}[/tex] molecules.

Therefore, molecules of S present in 33.76 moles are calculated as follows.

[tex]1 mol = 6.022 \times 10^{23}\\33.76 mol = 33.76 \times 6.022 \times 10^{23}\\= 2.032 \times 10^{25}[/tex]

Thus, we can conclude that there are [tex]2.032 \times 10^{25}[/tex] molecules [tex]S_{2}[/tex] gas are in 756.2 L.

Answer:

B. Potential energy

Explanation:

It's not mechanical energy, because it is not doing work

It's not kinetic energy because it;s not moving

It's not gravitational energy because it is not above the ground

It is potential energy because it is stored energy

Answer:

The second student with mass 70kg has more momentum

Explanation:

Using the formula:

p = m × v

Where;

p = momentum (kgm/s)

m = mass (kg)

v = velocity (m/s)

According to this question, two students are running in a cross country race.

Student 1 has the following; m = 60kg, v = 7m/s

Student 2 has the following; m = 70kg, v = 7m/s

Using p = mv

Student 1, p = 60 × 7 = 420 kgm/s

Student 2, p = 70 × 7 = 490 kgm/s

From the result of the above calculations, student 2 with mass 70kg has more momentum.

Explanation:

magnesium and sodium because they are minerals and part of iron

Explanation:

Weight loss and weight maintenance.

Muscle gain.

Improved mood.

Improved heart health.

Answer:

Hi , your answer is that At impact, the cue ball stops, but transfers all of its momentum and kinetic energy to the other ball, resulting in the hit ball rolling with the initial speed of the cue ball. In an inelastic collision, momentum is conserved, but the total kinetic energy of the system is not conserved

Explanation:

i really hope i helped , pleae give me brainliest , have a nice day and thank you in advance :) .