Can someone help me on this

Answer:

Four seasons occur on Earth

Explanation:

When the Earth has completely one revolution around the Sun, then it has completed 1 year, and four seasons have occurred in the meantime.

Four seasons occur on Earth when the Earth completes a revolution around the Sun.

The following points can be considered:

Therefore the correct answer is Four seasons occur on Earth.

Learn more about Earth:

https://brainly.com/question/18203196

Answer:

1.. Lanthanides and actinides are kept separately in the modern periodic table Why?

Lanthanides and actinides are kept separately in the modern periodic table because of following reason:

Explanation:

2. Differentiate between long period and short period in any two points.

Long period:

short period:

Answer:

b.troposphere

Explanation:

pls mark me brainliest

The number of moles of reactants and products can be used to obtain the mass of products formed. The results obtained are as follows;

The question says that HCl was in excess. It means that after the reaction, we will have unreacted HCl(aq) and  ZnCl2(aq) in the remaining solution.

Hence;

Mass of ZnCl2(aq) formed = 36.309g - 35.123g  = 1.186g

Number of moles ZnCl2(aq) formed = [tex]\frac{mass of ZnCl2(aq) formed}{molar mass of ZnCl2}[/tex]

[tex]\frac{1.186g}{136.286 g/mol}[/tex] = 0.0087 moles

From the reaction equation;

[tex]Zn (s) + 2HCl(aq) - > H2(g) + ZnCl2 (aq)[/tex]

To obtain the amount of Zn reacted

1 mole of Zn yields 1 mole of ZnCl2

x moles of Zn yields 0.0087 moles of ZnCl2

x = 0.0087 moles of Zn

a) 1 mole of Zn yields 1 mole of H2

0.0087 moles of Zn yields 0.0087 moles of H2

Mass of H2 = 0.0087 moles of H2 * 2 g/mol = 0.0174 grams

b)

Mass of Zn reacted =  0.0087 moles of Zn * 65.38 grams/mole = 0.5688 grams

c)

Percentage of Zn in the alloy = 0.5688 grams/1.203g * 100 = 47.3 %

https://brainly.com/question/14595258

Answer:

Density=mass/volume

= 570/2280

=0.25g/ml

Answer:

It's C. Ethanol produces hydrogen when it burns

When burned, ethanol produces water and CO2.

Answer:

Explanation:

Data are the facts, figures, and other evidence gathered through observations.

Answer:

13.8g

Explanation:

Remember that density is equal to mass over volume

d=m/v

rearrange the problem and you get dv=m

(0.92g/mL)(15mL)=13.8g

Answer:

this answer is b no u can it very easy

Explanation:

because solid and liquid can compress easily

plz support me

Answer:

A. move very little, so it cannot easily change its shape.

Answer:

~58.3 mL

Explanation:

m1*v1=m2*v2 --> (12.0 M HCL) * v1 = 350mL * 2.0M HCL

--> 350*2.0 = 700

--> 700/12.0 M HCL = 58.3 mL repeating

Answer:

2

Explanation:

2×2

2O

soooo

2H2O means 4H2O

Answer:

you tilt the cylinder at a slight angle so that the metal slides down the sides, rather than drops all it`s weight to the bottom

Answer:

1.23x10^24 atoms/6.022x10^23 atom/mol = 2.04 mol H20

Explanation:

Answer:

The empirical formula is the formula with a minimum whole number ratio of the constituent atoms present in a molecule. While the molecular formula has the actual number of atoms of various elements present in the molecule of the substance.

Empirical formula is C₃H₄O₃

Molecular formula is C₆H₈O₆

[tex]C_{x}[/tex][tex]H_{y} O_{z}[/tex] + O₂ ⟶ xCO₂ + [tex]\frac{y}{z} H_{2} O[/tex]

From online sources, molar mass of CO₂ = 44 g/mol

number of moles of CO₂ = 12.81/44 = 0.291m mol

Mass of carbon in it is; C = 12 × 0.291 = 3.492 mg

molar mass of water = 18 g/mol

number of moles of water in it = 3.5/18 = 0.194m mol

Hydrogen has 2 nos in water and so;

number of moles of hydrogen = 2 × 0.194 = 0.388m mol

Mass of hydrogen = 1 × 0.388 = 0.388 mg

Oxygen mass = 8.544 - (3.492 + 0.388) = 4.664 mg

Similarly, moles of oxygen that has molar mass of 16 is;

no of moles of oxygen = 4.664/16 = 0.2915m mol

Ratio of C:H:O is; 0.291:0.388;0.2915

Simplifying this gives us the empirical formula ratio as;

3:4:3

Thus;

Empirical formula is C₃H₄O₃

We are told that the molar mass of the compound is 176.1 g/mol.

Thus;

Molecular formula is; (176.1/88)C₃H₄O₃ = C₆H₈O₆

Read more at; brainly.com/question/14853529

Answer:

density is the sum of the mass and volume of an object

Answer:

7500000cm/hr

Explanation:

6km=600000cm

24min=24/60hr=0.4hr

so, according to the question

6k/24km=600000cm÷0.4hr

=1500000cm/hr

therefore in 5 hours we can run:

5×1500000cm/Hr

=7500000cm/hr

A person can run "7,500,000 cm" in 5 hours.

According to the question,

A person can run 6 km in 24 minutes, i.e.,

= [tex]\frac{6}{24} \ km/min[/tex]

and,

5 hours = 300 minutes

then,

→  A person can run in 5 hours:

= [tex]\frac{6}{24}\times 300[/tex]

= [tex]\frac{1800}{24}[/tex]

= [tex]75 \ km[/tex]

By converting km into cm, we get

= [tex]7500000 \ cm[/tex]

So the above is the right answer.

Learn more:

https://brainly.com/question/19035673

It causes the particles to vibrate and this causes the neighbouring particles to vibrate.

this process is continued until particles at the other vibrates.hence heat is transmitted from one place to another .Also it causes electrons to collide with the atoms of the metal.

Answer:

1, just I) color.

Explanation:

Physical properties are the properties that can be observed without changing the composition of a substance, such as color, temperature, density, and boiling point.

A physical change is a change in the substance that only modifies its aggregation state, such as solidification, and boiling.

Chemical properties are the properties that need a reaction to being observed, such as combustibility, which needs a combustion reaction to being quantified.

When a chemical reaction occurs, and the composition of the substance change, it's a chemical change.

So, heating copper with carbon is a chemical reaction, and purification by electrolysis is too. Color is the only physical property.

The product of a chemical reaction is what is remaining at the end of the reaction. The combination between reactant to form products can happen in a variety of ways including combination of ions in a solution to form new compounds

The correct compounds representing the variables and the net ionic equations are as follows:

a) A = NaCl

B = H₂O

Balanced net ionic equation: OH⁻(aq) + H⁺(aq) → H₂O (l)

ΔHrxn = Negative

b) C = NH₃

D = NaCl(aq)

E = H₂O(l)

Balanced net ionic equation: OH⁻(aq) + NH₄⁺(aq) → NH₃(aq) + H₂O(l)

ΔHrxn = Negative

c) F = NH₄Cl(aq)

Balanced net ionic equation: H⁺(aq) + NH₃(aq) → NH₄⁺(aq)

ΔHrxn = Negative

The reason the above values are correct are as follows:

a) Part (i)

The given chemical equation is

NaOH(aq) + HCl(aq) → A(aq) + B(l)

The chemical equation is the reaction between sodium hydroxide NaOH (aq) and hydrochloric acid HCl (aq), the product of the reaction is sodium chloride and water as follows;

NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O(l) + Heat

Therefore, we have;

A = NaCl, and B = H₂O

Part (ii)

The ionic equation is given as follows;

Na⁺(aq) + OH⁻(aq) + H⁺(aq) + Cl⁻(aq) → Na⁺(aq) + Cl⁻(aq) + H₂O (l)

Given that Na⁺(aq) and Cl⁻(aq) are spectator ions in the reaction, we have the balanced net ionic equation given as follows;

Balanced net ionic equation: OH⁻(aq) + H⁺(aq) → H₂O (l)

Part (iii)

ΔHrxn = Negative

b) Part (i)

The given chemical equation is NaOH(aq) + NH₄Cl(aq) → C(aq) + D(aq) + E(l)

The given reaction is between sodium hydroxide, NaOH(aq) and ammonium chloride, NH₄Cl(aq) and the products of the reaction are dissolved ammonia NH₃(aq), sodium chloride NaCl(aq), and water H₂O(l)

Therefore, we have;

NaOH(aq) + NH₄Cl(aq) → NH₃(aq) + NaCl (aq) + H₂O(l) + Heat

Therefore;

C = NH₃, D = NaCl(aq), E = H₂O(l)

Part (ii)

The ionic equation for the reaction is given as follows;

Na⁺(aq) + OH⁻(aq) + NH₄⁺(aq) + Cl⁻(aq) → NH₃(aq) + Na⁺(aq) + Cl⁻(aq) + H₂O(l)

The Na⁺(aq) and Cl⁻(aq) occur in both the reactants and products, therefore, they cancel out as spectator ions and we have;

Balanced net ionic equation: OH⁻(aq) + NH₄⁺(aq) → NH₃(aq) + H₂O(l)

Part (iii)

ΔHrxn = Negative

c) Part (i)

HCl(aq) + NH₃(aq) → F(l)

The given reaction is between hydrochloric acid and aqueous ammonia which has the product as ammonium chloride, NH₄Cl

Therefore, the reaction is given as follows;

HCl(aq) + NH₃(aq) → NH₄Cl(aq) + Heat

∴ F = NH₄Cl(aq)

Part (ii)

The ionic equation is given as follows;

H⁺(aq) + Cl⁻(aq) + NH₃(aq) → NH₄⁺(aq) + Cl⁻(aq)

Therefore, the chlorine ion Cl⁻(aq) occurs in both the reactant and product and can therefore, can be canceled out, and we have;

Balanced net ionic equation: H⁺(aq) + NH₃(aq) → NH₄⁺(aq)

Part (iii)

ΔHrxn = Negative

Learn more about balanced net ionic equation here:

https://brainly.com/question/2525785

Explanation:

Volume = FL - SL

= 39 - 33

= 6

Answer:

2C2H2 + 5O2 → 4CO2 + 2H2O

Explanation:

Answer:  132 liters. or 130 liters with 2 sig figs.

Explanation:  Use the ideal gas law:  PV = nRT

We want V, so rewrite and plug in data:

Temperture must be in Kelvin (add 273.15 to

V = (nRT)/P

V = (4.9 moles)*(0.0821 L*atm/molK)*(328.2K)/(1atm)

V = 132 liters (3 sig figs).  130 liters with 2 sig figs

Answer:

It would take sound 104.998 seconds to travel across lake tahoe.

Explanation:

First let's convert the miles to meters, so, 21.6 miles = 34754.4 meters

Now, we will divide this number in meters by 331. So, 34754.4 / 331 = 104.998

And what will the unit be? Seconds will be the unit for time here so 104.998 seconds.

Answer:

white

Explanation:

Answer:

it's yellowish in color plz Mark me as brainliest

Answer:

It's a yellowish color like copper

Its B) Boron and Oxygen

The correct answer is B.

boron and oxygen have the same number of energy levels with electrons in them.

The energy level of an element is the region around the nucleus where its electron is likely to be, this corresponds to the period of the element in the periodic table.

Elements found in period 1, have one energy level.

Elements found in period 2, have two energy level.

Examples of elements found in period 2 include:

In the given options, only option B contains two elements with 2 energy level.

Thus, boron and oxygen have the same number of energy levels with electrons in them.

Learn more here: https://brainly.com/question/18616411

Answer:

15000000

Explanation:

30000 x 500=15000000. I believe... lemme know if I was wrong, hope this helps <3.