Can someone help me please?!!!!!

Answer:

Simply identify what elements are in a compound

Explanation:

For example in NaCl we have sodium (Na) and Chlorine (Cl)

In order to do this you would need to recognise the symbols for a certain element: O for oxygen; N for nitrogen; H for hydrogen etc.

Answer:

Explanation: Mg(s) + CuSO4 (aq) -> Cu(s) + MgSO4 (aq)

Answer:

76

Explanation:

Mass number = number of protons plus the number of neutrons

So, 36 + 40 = 76

Answer:

C.

Explanation:

Slightly negative near the oxygen atom and slightly positive near the hydrogen atoms

Answer:

The correct answer is - An envelope of plasma surrounding the sun.

Explanation:

In the provided diagram the C labeled part of the sun is an envelope of plasma surrounding the sun which is called Solar Corona which makes the outermost layer of the atmosphere of the sun. Solar Corona is hotter in comparison to the surface of the sun itself.

Solar Corona is made up of the fourth state of matter known as plasma that has its magnetic field that determined its structural characteristics. Thus, the correct answer is an envelope of plasma surrounding the sun.

Answer:

person above is correct

Explanation:

I took the quiz and got it right.

Answer:

98.8g (3 s.f.)

Explanation:

Use the mole = mass/mr equation to find the moles of CaO, then use the molar ratio to find the moles of Fe2O3, which is the same as CaO, (assuming the ratio is 1:1, as you haven't stated it clearly in the question). Then use the equation and input to find Mass, which is 98.8g to 3 s.f.

Answer:

1.) protons or electrons 2.) ion

Explanation:

Answer:

A

Explanation:

because need more number to complete the balance equation

Answer:

78 ml

Explanation:

Answer:

10.57% of N in acetanilide

Explanation:

All nitrogen in the sample is converted in NH₃ in the Kjeldahl determination. The NH₃ reacts with H₂SO₄ as follows:

2NH₃ + H₂SO₄ → 2NH₄⁺ + SO₄²⁻

The acid in excess in titrated with Na₂CO₃ as follows:

Na₂CO₃ + H₂SO₄ → Na₂SO₄ + H₂O + CO₂

To solve this question we must find the moles of sodium carbonate = Moles of H₂SO₄ in excess. The added moles - Moles in excess = Moles of sulfuric acid that reacts:

Moles Na₂CO₃ anf Moles H₂SO₄ in excess:

0.025L * (0.05mol / L) = 1.25x10⁻³ moles Na₂CO₃ / 0.01360L =

0.09191M * 0.250L = 0.0230 moles H₂SO₄ in excess.

Moles H₂SO₄ added:

0.050L * (0.50mol / L) = 0.0250 moles H₂SO₄ added

Moles that react:

0.0250 moles - 0.0230 moles = 0.0020 moles H₂SO₄

Moles of NH₃ = Moles N:

0.0020 moles H₂SO₄ * (2mol NH₃ / 1mol H₂SO₄) = 0.0040 moles NH₃ = Moles N

mass N and mass percent:

0.0040 moles N * (14g / mol) = 0.056gN / 0.53g * 100 =

Answer:

Option A

Explanation:

As we know  

Percent yield is the ratio of actual yield/theoretical yield

a) Percent yield  - Theoretical yield 52.3 g; actual yield 50.7g = 0.97 = 97%

b) Percent Yield - Theoretical yield 17.1 g; actual yield 15.7g = 92%

c) Percent Yield - Theoretical yield 38.8 g; actual yield 36.2 g = 93%

d) Percent Yield - Theoretical yield 24.6 g; actual yield 22.5 g = 91%

Hence option A is correct

Answer:

3.60X10^-12 is equal to 0.360X10^-11 (move decimal one place left)

Now you can add 3.60X10^-11 and 0.360X10^-11:

3.60X10^-11 + 0.360X10^-11 = 3.96X10^-11

You're really just adding 3.60 to 0.36 since the "X10^-11" is the same for both.

Answer:

I think c.............

Answer:

C4H10 + 502 -> CO2 + 5H20

......

.......

Answer:

1. an educated guess

2. data

3. what changes in experiment

4. what stays the same in both groups

5. the group where nothing changes, normal

6. group with independent variable, what's being tested

Answer:

The warm exhaust from the natural gas heater

is the result of taking usable energy (in the

natural gas), using some of it, then releasing

the less usable form (exhaust). or you can write -> Electricity is a usable form of energy, but heat is not. Heat is simply dissipated to the surroundings as a result of temperature gradient. Thus, energy is transformed from usable to non-usable form.

Answer:

The mass of carbon dioxide formed is 12g.

Answer:

D

Explanation:

Answer:

Substances that absorb energy in the form of heat are

b)endothermic.

hope it helps :)

Answer:

K

Explanation:

Ionisation energy is the energy required for electron loss and the higher the occupied energy levels=higher atomic radius=the lower the ionisation energy thus k=2.8.8.1

Na=2.8.1

Li=2.1

Answer:

Henry Moseley was an English physicist whose contribution to the science of physics was the justification from physical laws of the previous empirical and chemical concept of the atomic number.

Answer:

90% of people marry there 7th grade love. since u have read this, u will be told good news tonight. if u don't pass this on eight comments your worst week starts now this isn't fake. apparently if u copy and paste this on ten comments in the next ten minutes you will have the best day of your life tomorrow. you will either get kissed or asked out in the next 53 minutes someone will say i love you.!Explanation:

Ammonia acts as a weak base in aqueous solution. Water is the acid that reacts with this base when ammonia is dissolved in water.

According to the Arrhenius concept, base is defined as a substance which yields hydroxyl ions on dissociation.These ions react with the hydrogen ions of acids to produce salt in an acid-base reaction.

Bases have a pH higher than seven as they yield hydroxyl ions on dissociation.They are soapy in touch and have a bitter taste.According to the Lowry-Bronsted concept, base is defined as a substance which accepts protons .Base react violently with acids to produce salts .Aqueous solutions of bases can be used to conduct electricity .They can also be used as indicators in acid-base titrations.

They are used in the manufacture of soaps,paper, bleaching powder.Calcium hydroxide ,a base is used to clean sulfur dioxide gas while magnesium hydroxide can be used as an antacid to cure acidity.

Learn more about base,here:

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