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2 years ago

Bronze contains 90 to 95 percent copper and 5 to 10 percent tin. Because these percentages can vary, bronze is classified as

2 answers:

8 0

Answer: a mixture.

Justification:

1) Pure substances have a definite chemical formula: the same kind of atoms with the same fixed ratios and chemical bonds. Therefore, the percents of each element do not varye.


2) Elements and compounds are pure substaces. For example, Fe, Mg, Ti, are elements, and CO₂, CO, H₂CO₃ are compounds. Each of them will have always the same kind of atoms, in the same ratio and with the same chemcial bonds. Therefore the percents of the elements do not varye.


3) Mixtures are formed by the physical combination (not chemical bonds) of different elements or compounds in variable proportions. As indicated, this describes the material bronze, in virtue of the variation of its composition. Other examples of mixtures are solutions (like brines), air, ocean water, and milk: different brines, different oceans and different milk have different contents of elements or compounds.

san4es73 [151]2 years ago

4 0

Answer:

it is a mixture

Explanation:

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A sample of gas occupies 10 L at STP. What

puteri [66]

Pressure is 5.7 atm

Explanation:

P1 = Standard pressure = 1 atm

P2 = ?

V1 = Volume = 10L

V2= 2.4L

T1 = 0°C + 273 K = 273 K

T2 = 100°C + 273 K = 373 K

We have to find the pressure of the gas, by using the gas formula as,

$$\frac{P 1 V 1}{T 1}=\frac{P 2 V 2}{T 2}$

P2 can be found by rewriting the above expression as,

$$P 2=\frac{P 1 \times V 1 \times T 2}{T 1 \times V 2}$

Plugin the above values as,

$$P 2=\frac{1 \text {atm} \times 10 L \times 373 \mathrm{K}}{273 \mathrm{K} \times 2.4 \mathrm{L}}=5.7 \text { atm }$

4 0

1 year ago

The easiest way to determine whether a process is exothermic or endothermic is to note the change in temperature in a calorimete

Kryger [21]

Answer:

In the calorimeter, water is the exothermic. The salt LiCI, which will dissolve, is the endothermic. The final temperature of the water after the dissolution of LiCI was lower than the initial temperature, meaning the process is exothermic. In the microscopic view of the disspolution of LiCI, water molecules were seen to move slowly as they gained energy.

Explanation:

Exothermic is a process in which heat is released during the process. Endothermic reactions absorbs heat from surrounding during a chemical process. The dissolution of salt into water is an exothermic reaction. During this process heat is release and water molecules are broken down which are surrounded by salt ions.

5 0

1 year ago

A sample of copper with a mass of 63.5g contains 6.02 x10^23 atoms calculate the mass of an average copper atom

m_a_m_a [10]

Answer:

The mass of an average copper atom is $1.0548\times 10^{-22}\ g$

Explanation:

Given:

The total mass of copper atoms, $m = 63.5\ g$

Number of atoms, $N=6.02\times 10^{23}$

Now, we are asked to find the mass of 1 copper atom.

We use unitary method to find the mass of 1 copper atom.

Mass of $N$ atoms = m

∴ Mass of 1 atom = $\frac{m}{N}$

Plug in 63.5 for 'm', $6.02\times 10^{23}$ for 'N' and simply.

Mass of 1 atom = $\dfrac{63.5}{6.02\times 10^{23}}=1.0548\times 10^{-22}\ g$

Therefore, the mass of an average copper atom is $1.0548\times 10^{-22}\ g$

5 0

1 year ago

Which pairs of reactants will result in a chemical reaction? Refer to the activity series as needed. Pb ( s ) + MgCl 2 ( aq ) Pb

GrogVix [38]

Answer:

Al (s) + AgClO3 (aq) will result in a chemical reaction.

Al(s) + 3AgClO₃(aq) -----> Al(ClO₃)₃(aq) + 3Ag(s)

Cd(s) + CuNO3(aq) will also result in a chemical reaction.

Cd(s) + 2CuNO₃ -----> Cd(NO₃)₂ + 2Cu

Explanation:

For chemical reactions, metals lower on the activity series cannot normally displace ions of metals higher than them in the activity series.

Metals at the lower end of the activity series are not easily oxidized.

The activity series is attached to this solution. (Note: Cadmium is not on the attached chart, but Cadmium is between Iron (Fe) & Cobalt (Co) on the activity series)

- Pb is way lower Mg in the activity series, hence, it cannot become oxidized by displacing Mg2+ ion in solution.

- Al is way higher than Ag in the activity series. Hence it will easily be oxidized and displace displace Ag from it's solution easily.

- Cadmium will displace Copper in solution too because Cd is higher than Cu on the activity series.

- Platinum cannot displace Cobalt from solution as Pt is lower than Co on the activity series.

4 0

1 year ago

How many pints of a 30% sugar solution must be added to a 5 pint of a 5% sugar solution to obtain a 20% sugar solution?

ser-zykov [4K]

You must add 7.5 pt of the 30 % sugar to the 5 % sugar to get a 20 % solution.

You can use a modified dilution formula to calculate the volume of 30 % sugar.

V_1×C_1 + V_2×C_2 = V_3×C_3

Let the volume of 30 % sugar = x pt. Then the volume of the final 20 % sugar = (5 + x ) pt

(x pt×30 % sugar) + (5 pt×5 % sugar) = (x + 5) pt × 20 % sugar

30x + 25 = 20x + 100

10x = 75

x = 75/10 = 7.5

5 0

1 year ago