Which of the following metals would be the best to choose for making jewellery? Aluminium, iron, copper or gold?

Answer:

The acid will absolutely remove the hard water deposits that are trapping the stains. The longer it soaks, the less you have to scrub. It works for hard water stains, limescale, and rust!

Explanation:

hope this helped you out.

Answer:

-205.7kj

Explanation:

Now adding reaction 2 and twice of reaction 3 and reverse of reaction 1, we get the enthalpy of the reaction.

The expression for enthalpy for the following reaction will be,

where,

n = number of moles

Now put all the given values in the above expression, we get:

Therefore, the enthalpy of the following reaction is,  -205.7kj

Answer:

B. Moderately active metal

Explanation:

Answer:

The answer copper carbonate

Answer:

The limiting reactant is copper (II) chloride

Explanation:

here you go

Answer:

12.1-M requires less volume of stock solution.

Explanation:

Hello there!

In this case, according to the foundations of dilution processes, it turns out convenient to remember that the moles of the solute before and after the dilution remains the same; for that reason we use the following equation:

[tex]M_1V_1=M_2V_2[/tex]

Relating the initial and final molarities and volumes. Now, it is seen that V2 is 10.0 mL and M2 is 1.0 M, which means that if we solve for V1 for 12.1 M and 6.0 M, we obtain the following volumes:

[tex]V_1=\frac{M_2V_2}{M_1} \\\\V_1^{12.1M}=\frac{1.0M*10.0 mL}{12.1M}=0.826mL\\\\V_1^{6.0M}=\frac{1.0M*10.0 mL}{6.0M}=1.67mL[/tex]

Therefore, since the 12.1-M solution requires less volume of stock solution, it makes sense to use this one as the initial solution.

Best regards!

Answer:

Explanation:When silver Ag metal is added to copper sulphate CuSO4 solution, no reaction takes place as silver is less reactive than that of copper and cannot displace copper from its solution. Hence, when a piece of silver metal is added to copper sulphate solution there will be no reaction.

Answer:

There will be no reaction

Explanation:

Therefore, when silver Ag metal is added to copper sulphate CuSO4 solution, no reaction takes place as silver is less reactive than that of copper and cannot displace copper from its solution. Hence, when a piece of silver metal is added to copper sulphate solution there will be no reaction.

Answer:

82.04g

Explanation:

To solve this problem, you need to find the molar mass of HCl, which is the sum of the molar mass of H plus the molar mass of Cl. The molar mass of H is 1.008g/mol while the molar mass of Cl is 35.45g/mol. Thusly the molar mass of HCl is 36.458g/mol. You have 2.25 moles of HCl, so multiply the number of moles by the molar mass to get the mass in g. In this case it is 2.25mol * 36.458g/mol = 82.04g.

If I helped, a brainliest would be greatly appreciated!

Answer:

When you exercise and your muscles work harder, your body uses more oxygen and produces more carbon dioxide.

Explanation:

Because your muscles are working harder when you exercise, your body requires more oxygen and produces more carbon dioxide.

Exercise is characterized as a physiological movement that maintains or enhances total physical wellness. People who exercise are less likely to get diseases and to maintain a healthy weight. Type 2 diabetes, heart disease, high blood pressure, and weight gain can all be warded off with regular exercise. Leaping, jogging, or lifting weights are examples of exercises that can support bone health.

The lungs both provide the body with oxygen, which gives you energy, and remove carbon dioxide from the system, which is a byproduct of energy production. The heart pumps oxygen-rich blood to the working muscles. Because your muscles are working harder when you exercise, your body requires more oxygen and produces more carbon dioxide.

Thus, because your muscles are working harder when you exercise, your body requires more oxygen and produces more carbon dioxide.

To learn more about exercise, refer to the link below:

https://brainly.com/question/13128077

#SPJ2

Answer:

density= mass/volume

hence density of gold rock

= 386/20

=19.3 g/cc

Answer: The percent by mass concentration is 33.3 %

Explanation:

Mass percent is the ratio of mass of solute to the mass of solution in terms of percentage.

mass of solute = 50 g

mass of solution = [tex]{\text {density of solution}}\times {\text {volume of solution}}=1.5g/ml\times 1000ml=1500g[/tex]

Mass percentage = [tex]\frac{50g}{1500g}\times 100\%=33.3\%[/tex]

Thus percent by mass concentration of 1000 ml of a solution (d=1.5 g/ml) that contains 50 g of solute in it is 33.3 %

Answer:

pH = 9.37

Explanation:

The reaction of HZ with NaOH occurs as follows:

HZ + NaOH → H₂O + Na⁺ + Z⁻

When the reaction is in the equivalence point, the moles added of HZ = Moles of NaOH.

At equivalence point, you will have in solution just NaZ that is in equilibrium with water as follows:

Z⁻(aq) + H₂O(l) ⇄ OH⁻(aq) + HZ(aq)

Where K of equilibrium is Kw / Ka = 1x10⁻¹⁴ / 2.4x10⁻⁶ = 4.17x10⁻⁹

And K is defined as:

K = 4.17x10⁻⁹ = [OH⁻] [HZ] / [Z⁻]

To solve this question we must find  [Z⁻] and as [OH⁻] and [HZ] comes from the same equilibrium, both are equal and we can find [OH⁻] in order to solve pH:

Moles NaOH added = Moles HZ:

0.010L * (0.39mol / L) = 3.9x10⁻³ moles HZ = Moles NaOH added

The volume of 0.200M NaOH must be:

3.9x10⁻³ moles * (1L / 0.200moles) = 0.0195L.

The moles of HZ = Moles Z⁻ after the reaction and the volume is 0.010L + 0.0195L = 0.0295L. Thus, [Z⁻] is:

[Z⁻] = 3.9x10⁻³ moles / 0.0295L

[Z⁻] = 0.132M

Replacing in K expression:

4.17x10⁻⁹ = [OH⁻] [HZ] / [Z⁻]

4.17x10⁻⁹ = [X] [X] / [0.132]

5.51x10⁻¹⁰ = X²

X = 2.35x10⁻⁵M = [OH⁻]

As pOH = -log [OH⁻]

pOH = 4.63

And pH is

pH = 14 -pOH

Answer:

For an electron they start at the first level (n=1) In order to move up to the next level (n=2) the amount of quantom energy to move to this next level the energy must be perfect in order to move. If the quantom energy is to small the electron it doesn't try.

Answer:

ye but sdfajkd tryng to play me

Explanation:

Answer:

Vapor is released out of the lemonade because when you place it in a hot it will increase.

Explanation:

Answer:

The correct answer is - increased the global average temperature.

Explanation:

Combustion is the process that increases the carbon dioxide in the atmosphere, which results in entering more energy into the Earth system than existed from it.  Therefore, the amount of energy increased in the system of the earth or surface of the earth.

The reason behind it is that carbon dioxide trapped and redirects energy back toward the Earth's surface, which is absorbed by Earth's surface and surface increased, and global average temperature increased.

Combustion process increases the global average temperature of the earth by absorbing and emitting the energy revert back to earth.

Combustion is a process exothermic process in which organic molecules burns in the presence of oxygen to produce energy in the form of heat and light and CO₂ gas.

CO₂ gas is a green house gas which traps the energy of the atmosphere and revert back it into the earth surface, due to which temperature of the earth surface and atmosphere increases which results in the elevation of global average temperature.

Hence, combustion increases the global average temperature.

To know more about combustion, visit the below link:

https://brainly.com/question/15246277

Answer:

M = 12.0M

Explanation:

Hello there!

In this case, according to the given by-mass percent of HCl, which can be set up in terms of mass of HCl over mass of solution, we can calculate the molarity, by multiplying by the density to get the mL's of solution and further convert to liters. Moreover, the molar mass of HCl (36.46 g/mol) must be also used to calculate the moles, since molar units requires moles of solute and liters of solution as shown below:

[tex]M=\frac{37.0gHCl}{100g\ sln}*\frac{1.18g\ sln}{1mL\ sln}*\frac{1000mL\ sln}{1L \ sln}*\frac{1molHCl}{36.46gHCl}\\\\M= 12.0M[/tex]

Best regards!

Answer: Trust me 100% plz its loss of habitat wat they said

Explanation:

Answer:

60g or 61.28g

Explanation:

Trust me on this I had the same problem as you

Answer: 9. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

10. The reasons for the differences in the surface temperature of terrestrial planets are due to their distance from the sun and the composition of their atmosphere.

11. 93.48 million miles

12. Iron core

Explanation: Hope this helped!! :)

Answer:

2H+(aq) + CaCO3(s) → Ca2+(aq) + H2O(l) +. CO2(g). [ 2]. Award [1] for correct reactants and products. Award [1] if the ... Exercises. 1 Reaction gives off a gas: change in volume could be measured.

Most of the matter making up earth is composed of compounds. I think

Answer:

67.5 gm H2O

Explanation:

2 H2   = 4 gm

O2 = 32 gm

2 H20 = 36 gm

so   32 gm O2   results in 36 gm H20

32/36  = 60/x     x = 67.5 gm

Answer:

1. Graphite rod (cathode)

2. Positive terminal

3. Solid zinc layer (anode)

4. Paste (reduction takes place here)

5. Negative terminal

Explanation:

This was the only thing i could find on it. hope this helps.

Answer:

Explanation:

• Label all parts.

1. Cathode or Graphite Rod

2. Positive terminal  

3. Anode or Solid Zinc layer  

4. Electrolyte Paste (reduction takes place here)

5. Negative Terminal (maybe this could also be the Zinc casing)  

• Label the cathode and the anode, including the charges on each.

The anode is the zinc layer is negatively charged and the cathode is the graphite rod is positively charged.  

• Show the flow of electrons.

The zinc casing is oxidized and the electrons flow along the zinc layer, into the negative terminal, and then out the negative terminal. The electrons move from the wire to the graphite rod. Then from the rod the electrons move to the paste, then the past goes through reduction. The anode gets a negative charge as electrons are released, and the cathode gets a positive charge as the electrons, which are negatively charged, are consumed.

• Explain how the cell works. Include the oxidation and reduction half-reactions in your explanation.

Alkaline dry cells use spontaneous oxidation-reduction reactions to convert chemical energy to electrical energy. According to the lesson ‘’Half-reactions are combined in a small casing, but still separated into half-cells.’’

4) H+ions is your answer , good morning , have a great day ahead.

Answer:

An earthquake

Explanation:

Answer:

Negative, because the potential energy of the reactants is higher than the potential energy of the products

Explanation:

Exothermic reaction is a reaction in which heat is released to surrounding. This is due to the fact that the heat content of the reactant is higher than the heat content of product thus producing a negative enthalpy change (ΔH) i.e

Enthalpy change = Heat of product – Heat of reactant

ΔH = Hp – Hr = negative

Considering the options given in the question above, the correct answer is:

Negative, because the potential energy of the reactants is higher than the potential energy of the products