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Anni [7]
3 years ago
5

Each element has three number listed under it which value represent the atomic

Chemistry
1 answer:
Natasha_Volkova [10]3 years ago
8 0

The atomic number is the number at the top.


The atomic number is equal to the number of protons in an atom's nucleus. The atomic number determines which element an atom is. For example, any atom that contains exactly 47 protons in its nucleus is an atom of silver.

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What do proteins act as?
Tresset [83]

Proteins are made from long chains of smaller molecules called amino acids. These long chains are folded into particular shapes. This is important in relation to how antibodies and enzymes work.

Enzymes are biological catalysts. There are optimum temperatures and pH values at which their activity is greatest. Enzymes are also proteins. If the shape of an enzyme changes, it may no longer work (it is said to have been 'denatured'). maybe right?


8 0
3 years ago
Why do you think some of the indicators used in experiment 2 were different than the ones used in experiment 1?
pentagon [3]

During selection of indicator. We choose an indicator which have pH range equivalent to the pH change of reaction to give better result and better observation.

So there are some different indicator are used in table 2 as compared to the table 1. 

- Alizarin and phenolphthalein are basic indicator and their pH range is more than 8 so they are used in table 2

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6 0
3 years ago
What is the mass of a rectangular cube with dimensions of 3 cm x 2 cm x to 10 cm and a density of 10 g/cm^3
marta [7]

d=m/V so m=Vd

m=60cm^3 * 10g/cm^3=600g

3 0
3 years ago
Read 2 more answers
What is the molar solubility of marble (i.e., [ca2 ] in a saturated solution in normal rainwater, for which ph=5.60? express you
Brut [27]
Missing in your question :

Ksp of(CaCO3)= 4.5 x 10 -9

Ka1 for (H2CO3) =  4.7 x 10^-7

Ka2 for (H2CO3) = 5.6 x 10 ^-11

1) equation 1 for Ksp = 4.5 x 10^-9 

CaCO3(s)→ Ca +2(aq)    +  CO3-2(aq)  

2) equation 2 for Ka1 = 4.7 x 10^-7

 H2CO3 + H2O → HCO3- + H3O+

3) equation 3 for Ka2 = 5.6 x 10^-11

 HCO3-(aq) + H2O(l) → CO3-2 (aq)  + H3O+(aq)

so, form equation 1& 2&3 we can get the overall equation:
CaCO3(s)  +  H+(aq)  → Ca2+(aq)   + HCO3-(aq)

note: you could get the overall equation by adding equation 1 to the inverse of equation 3 as the following:
when the inverse of equation 3 is :

CO3-2 (aq) + H3O+ (aq) ↔ HCO3- (aq) + H2O(l)  Ka2^-1 = 1.79 x 10^10
when we add it to equation 1
CaCO3(s) ↔ Ca2+(aq)  +  CO3-2(aq)   Ksp = 4.5 x 10^-9

∴ the overall equation will be as we have mentioned before:
when H3O+ = H+

CaCO3(s) + H+(aq)  ↔ Ca2+ (aq) + HCO3-(aq)   K= 80.55

from the overall equation:

∴K = [Ca2+][HCO3-] / [H+]

when we have [Ca2+] = [HCO3-] so we can assume both = X

∴K = X^2 / [H+]

when we have the PH = 5.6 so we can get [H+]

PH = - ㏒[H+]
5.6 = -㏒[H]
∴[H] = 2.5 x 10^-6

so, by substitution on K expression:

∴ 80.55 = X^2 / (2.5 x10^-6)

∴X = 0.0142

∴[Ca2+] = X = 0.0142 
6 0
3 years ago
How does a sample of hydrogen at 10 °C compare to a sample of hydrogen at 350 K?
Andrej [43]

Answer: -

C. The hydrogen at 10 °C has slower-moving molecules than the sample at 350 K.

Explanation: -

The kinetic energy of gas molecules increase with the increase in the temperature of the gas. With the increase in kinetic energy, the gas molecules also move faster. Thus with the increase of temperature, the speed of the molecules increase.

Temperature of first hydrogen gas sample is 10 °C.

10 °C means 273+10 = 283 K

Thus first sample temperature = 283 K

The second sample temperature of the hydrogen gas  is 350 K.

Thus the temperature is increased.

So both the kinetic energy and speed of molecules is more for the hydrogen gas sample at 350 K.

Thus the hydrogen at 10 °C has slower-moving molecules than the sample at 350 K.

Hence the answer is C.

7 0
3 years ago
Read 2 more answers
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