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Gwar [14]
3 years ago
5

How are the sizes of stars measured? I just need a simple answer

Chemistry
1 answer:
S_A_V [24]3 years ago
7 0
They are determined by the length of time it takes for light to travel from the Earth to the desired star
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If you have a sample of honey that has a mass of 20 grams what is the volume
tino4ka555 [31]
Not enough information to find the volume, unless the density of the substance was given or some container of honey with a measure in centimeters cube.
8 0
4 years ago
If a weak acid is 25 deprotonated at ph 4 what would the pka be
elena-s [515]

4.48

pH=pKa+log([A-/HA])

25% deprotonated tells us that A- is .25 and that the rest (75% is protonated) thats .75.

4 = pKa + log \frac{.25}{.75}

4 - log \frac{.25}{.75}  = pKa

4.48=pKa

6 0
3 years ago
Becky wants to model an ecosystem. Which of the following modeling tools would best help her illustrate an ecosystem?
Firdavs [7]

Answer:

c

Explanation:

5 0
3 years ago
if 1.386 g of mg ribbon combusts to form 2.309 g of oxide product, calculate the experimental mass percent of oxygen from this d
Pavlova-9 [17]

1.386 g of Mg ribbon combusts to form 2.309 g of oxide product. The mass percent of oxygen in the oxide is 40.0 %.

Let's consider the reaction for the combustion of Mg.

Mg + 1/2 O₂ ⇒ MgO

1.386 g of Mg combusts to form 2.309 g of MgO. We want to determine the mass of oxygen in MgO. According to Lavoisier's law of conservation of mass, matter is not created nor destroyed over the course of a chemical reaction. Then, the mass of Mg in the reactants is equal to the mass of Mg in MgO. The mass of the magnesium oxide is the sum of the masses of magnesium and oxygen. The <u>mass of oxygen in the oxide</u> is:

mMgO = mMg + mO\\mO = mMgO - mMg = 2.309 g - 1.386 g = 0.923 g

We can calculate the mass percent of O in MgO using the following expression.

\% O = \frac{mO}{mMgO} \times 100\% = \frac{0.923 g}{2.309g} \times 100\%  = 40.0 \%

You can learn more about mass percent here: brainly.com/question/14990953

3 0
2 years ago
Which best defines partial pressure in a mixture of gases?
VladimirAG [237]

Answer:

Pressure that is exerted by one gas as if it occupied a container by itself.

7 0
3 years ago
Read 2 more answers
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