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Charra [1.4K]
2 years ago
15

What is the apparent brightness of a star?

Chemistry
1 answer:
Rzqust [24]2 years ago
3 0

Answer:

it's bright where you can see it it's not that bright compared to the sun from Earth it's really not so bright

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In the chemical reaction, calcium carbonate (CaCO3) was heated to form two new
noname [10]

Answer: 10.99

Explanation: because you take the Cao 13.9 and take CO2 which is 10.99 and it makes 24.8 . Which is CaCO3.

8 0
3 years ago
A mixture of propane and butane is fed into a furnace where it is mixed with air. the furnace exhaust leaves the furnace at 305°
IgorLugansk [536]
In this item, I supposed, that we are determine the molar fraction of oxygen and carbon dioxide in the sample. This can be done by dividing their respective partial pressures by the total pressure of the sample.

   O2 : mole fraction = (100.7 mmHg) / (763.00 mmHg)  = 0.13

   CO2 : mole fraction = (33.57 mmHg) / (763.00 mmHg) = 0.044

Answers: O2 = 0.13
               CO2 = 0.044
3 0
3 years ago
In a 0.730 M solution, a weak acid is 12.5% dissociated. Calculate Ka of the acid.
Mamont248 [21]

Answer:

Approximately 1.30 \times 10^{-2}, assuming that this acid is monoprotic.

Explanation:

Assume that this acid is monoprotic. Let \rm HA denote this acid.

\rm HA \rightleftharpoons H^{+} + A^{-}.

Initial concentration of \rm HA without any dissociation:

[{\rm HA}] = 0.730\; \rm mol \cdot L^{-1}.

After 12.5\% of that was dissociated, the concentration of both \rm H^{+} and \rm A^{-} (conjugate base of this acid) would become:

12.5\% \times 0.730\; \rm mol \cdot L^{-1} = 0.09125\; \rm mol \cdot L^{-1}.

Concentration of \rm HA in the solution after dissociation:

(1 - 12.5\%) \times 0.730\; \rm mol \cdot L^{-1} = 0.63875\; \rm mol\cdot L^{-1}.

Let [{\rm HA}], [{\rm H}^{+}], and [{\rm A}^{-}] denote the concentration (in \rm mol \cdot L^{-1} or \rm M) of the corresponding species at equilibrium. Calculate the acid dissociation constant K_{\rm a} for \rm HA, under the assumption that this acid is monoprotic:

\begin{aligned}K_{\rm a} &= \frac{[{\rm H}^{+}] \cdot [{\rm A}^{-}]}{[{\rm HA}]} \\ &= \frac{(0.09125\; \rm mol \cdot L^{-1}) \times (0.09125\; \rm mol \cdot L^{-1})}{0.63875\; \rm mol \cdot L^{-1}}\\[0.5em]&\approx 1.30 \times 10^{-2} \end{aligned}.

5 0
3 years ago
A standard hydrogen atom has how many neutrons?<br> A. 0<br> B. 3<br> C. 2<br> D. 1
Anestetic [448]

Answer:

D. 1

Explanation:

Hydrogen is the chemical element with the symbol H and atomic number 1. With a standard atomic weight of 1.008, hydrogen is the lightest element in the periodic table. Hydrogen is the most abundant chemical substance in the Universe, constituting roughly 75% of all baryonic mass.

4 0
3 years ago
Read 2 more answers
Write a balanced chemical equation for this reaction by completing the reaction below. Add the missing products and coefficients
Pie

To balance a chemical equation you must pay attention that the algebraic equation has the same number of element atoms in reactant and the product.

A chemical equation is a term to refer to the symbolic description of a chemical reaction, that is, the written representation of symbols. For example:

  • 2H₂ + O₂ ---> 2H₂O

The balance of an equation can be related to the law of conservation of matter, that is, the number of atoms of each element in the reactants is in the result.

Note: This question is incomplete, because the information some information is missing.

Learn more in: brainly.com/question/12271256

6 0
2 years ago
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