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3 years ago

6

By studying a star's spectrum, scientists can work out its chemical make-up and temperature. What instrument do astronomers' use

to carry out this task?
A) space probe
B) spectroscope
C) radio telescope
D) light telescope

2 answers:

vredina [299]3 years ago

8 0

The answer is -
B) Spectroscope

Bess [88]3 years ago

5 0

B is the answer you are looking for

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Why is mining for coal a long-term concern?

Delvig [45]

Answer:

B

Explanation:

Coal is a non-renewable resource, so the supply can't produce faster than we can mine it.

8 0

2 years ago

Read 2 more answers

Aqueous potassium phosphate was mixed with aqueous magnesium chloride, and a crystallized magnesium phosphate product was formed

scoray [572]

<u>Answer:</u> The other product formed is potassium chloride.

<u>Explanation:</u>

Precipitation reaction is defined as the chemical reaction in which an insoluble salt is formed when two solutions are mixed containing soluble substances. The insoluble salt settles down at the bottom of the reaction mixture.

The chemical equation for the reaction of potassium phosphate and magnesium chloride follows:

$2K_3PO_4(aq.)+3MgCl_2(aq.)\rightarrow Mg_3(PO_4)_2(s)+6KCl(aq.)$

By Stoichiometry of the reaction:

2 moles of aqueous solution of potassium phosphate reacts with 3 moles of aqueous solution of magnesium chloride to produce 1 mole of solid magnesium phosphate and 6 moles of aqueous solution of potassium chloride.

Hence, the other product formed is potassium chloride.

4 0

4 years ago

Distinguish between the terms "insoluble" and "unsaturated." Give an example to illustrate each term.

Serjik [45]

Insoluble means that a substance does not dissociate in another, like mixing water and oil.

In an unsaturated solution, the solute does dissociate into solution but there is more "room" in the solution to hold more. Say if you have an amount of water that can dissolve 20g of salt but you only have 15g dissolved in it, that solution is unsaturated.

4 0

3 years ago

For the reaction of hydrogen with iodine

fenix001 [56]

Answer:

$r_{H_2} = \frac{-1}{2} r_{HI}$

Explanation:

Hello!

In this case, considering the given chemical reaction:

$H_2(g) + I_2(g) \rightarrow 2HI(g)$

Thus, by applying the law of rate proportions, we can write:

$\frac{1}{-1} r_{H_2} = \frac{1}{-1}r_{i_2} = \frac{1}{2} r_{HI}$

Whereas the stoichiometric coefficients of reactants are negative due their disappearance and that of the product is positive due to its appearance. In such a way, when we relate the rate of disappearance of hydrogen gas to the rate of formation of hydrogen iodide, we obtain:

$r_{H_2} = \frac{-1}{2} r_{HI}$

Best regards!

8 0

3 years ago

Determine the number of moles of the anhydrous salt present after heating, assuming that the contents of the aluminum cup after

lara31 [8.8K]

Answer:

0.2 moles, assuming weight of dried salt

Explanation:

In order to determine the number of moles, we need to be aware of the mass of the substance in question.

Assuming the mass of the dehydrated $KAl(SO_{4} )_{2}.H_{2} O$ is 50g.

No. of moles = mass of substance/ molar mass of the substance.

= $\frac{50g}{39+27+32*2+16*4*2\\)g/mol}$

= 0.2 moles moles.

6 0

3 years ago