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lions [1.4K]
3 years ago
12

Which two of these are also pure substances? Silicon Brass Gold Steel Rubber​

Chemistry
2 answers:
bija089 [108]3 years ago
5 0
Silicon and gold, both are elements on the periodic table. the rest are alloids or compounds.
meriva3 years ago
4 0
The answers is rubber and gold
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how much heat is released when 70.9g of water at 66C cools to 25C? The specific heat of water is 1 cal/gC
Serga [27]

Answer:

-12162.47 joules (or -12000 joules when accounting for significant figures)

Explanation (btw I used 1 cal as 4.184 joules because SI units are better):

q = m c delta T

q = (70.9) (4.184) (25 - 66)  

q = (70.9) (4.184) (-41)

q = -12162.47 joules

7 0
3 years ago
Which statement describes the use of a flowchart?
castortr0y [4]

Answer: I believe it is B

5 0
3 years ago
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The reaction below demonstrates which characteristic of a base?
svlad2 [7]

Answer: option D. the ability of a base to react with a soluble metal salt.


Justification:


NaOH is a strong base, which means that in water it will dissociate according to this reaction:


  • NaOH(aq) → Na⁺ (aq) + OH⁻ (aq)

On the other hand, CuSO₄ is a soluble ionic salt which in water will dissociate into its ions according to this other reaction:

  • CuSO₄(aq) → Cu²⁺ + SO₄²⁻

Hence, in solution, the sodium ion (Na⁺) will  react with the metal salt in a double replacement reaction, where the highly reactive sodium ion (Na⁺) will substitute the Cu²⁺ in the CuSO₄ to form the sodium sulfate salt, Na₂SO₄ (water soluble), and the copper(II) hydroxide, Cu(OH)₂ (insoluble).


That is what the given reaction represents:


  CuSO₄ (aq)     +     2NaOH(aq)    →    Cu(OH)₂(s)       +     Na₂SO₄(aq)

         ↑                                ↑                         ↑                            ↑

soluble metal salt       strong base       insoluble base       solube salt



5 0
4 years ago
Read 2 more answers
Which is false HCI + CaCO3
tekilochka [14]

Answer:

CaCO3 is false

Explanation:

Because HCl is hydrongen chloride

7 0
3 years ago
For the reaction 2 H2S(g) D 2 H2 (g) + S2 (g), Kp = 1.5 × 10−5 at 800.0°C. If the initial partial pressures of H2 and S2 in a cl
Usimov [2.4K]

Answer: The approximate equilibrium partial pressure of H_2S is 3.92  atm

Explanation:

Equilibrium constant is the ratio of the concentration of products to the concentration of reactants each term raised to its stochiometric coefficients.

The given balanced equilibrium reaction is,

      2H_2S(g)\rightleftharpoons 2H_2(g)+S_2(g)

K_p=\frac{[H_2]^2\times [S_2]}{[H_2S]^2}

1.5\times 10^{-5}=\frac{[H_2]^2\times [S_2]}{[H_2S]^2}

On reversing the reaction:

     2H_2(g)+S_2(g)\rightleftharpoons 2H_2S(g)

initial pressure  4.00atm    2.00 atm       0

eqm          (4.00-2x)atm      (2.00-x) atm      2x atm

K_p=\frac{[H_2S]^2}{[H_2]^2\times [S_2]}

K_p'=\frac{1}{K_p}=0.67\times 10^5

2H_2(g)+S_2(g)\rightleftharpoons 2H_2S(g)

0.67\times 10^5=\frac{2x]^2}{[4.00-2x]^2\times [2.00-x]}

x=1.96

[H_2S]=2x=2\times 1.96=3.92 atm

Thus approximate equilibrium partial pressure of H_2S is 3.92 atm

3 0
3 years ago
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