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3 years ago

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What are some signs that a chemical change takes place when a firework explodes? Matter is destroyed Light is produced Heat is p

roduced The chemical composition is not changed

1 answer:

Radda [10]3 years ago

4 0

Well, the answer relies on all four factors, I mean on all options. So, the answer is A, B, C, and D.

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PLEASE HELP!!!!!<br><br> Calcium hydroxide is _____.<br><br> an acid<br> a base<br> a neutral

Bingel [31]

I believe it is a base!

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3 years ago

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How many grams of sodium are in<br> 1.000 mole of sodium?

jolli1 [7]

Answer:

Explanation:

How many atoms are in a 3.5 g sample of sodium (Na)? In this example, multiply the grams of Na by the conversion factor 1 mol Na/ 22.98 g Na, with 22.98g being the molar mass of one mole of Na, which then allows cancelation of grams, leaving moles of Na.

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A 250 mL sample of gas is collected over water at 35°C and at a total pressure of 735 mm Hg. If the vapor pressure of water at 3

ELEN [110]

Answer:

The volume of the gas sample at standard pressure is <u>819.5ml</u>

Explanation:

Solution Given:

let volume be V and temperature be T and pressure be P.

$V_1=250ml$

$V_2=?$

$P_{total}=735 mmhg$

1 torr= 1 mmhg

42.2 torr=42.2 mmhg

so,

$P_{water}=42.2mmhg$

$T_1=35°C=35+273=308 K$

Now

firstly we need to find the pressure due to gas along by subtracting the vapor pressure of water.

$P_{gas}=P_{total}-P_{water}$

=735-42.2=692.8 mmhg

Now

By using combined gas law equation:

$\frac{P_1*V_1}{T_1} =\frac{P_2*V_2}{T_2}$

$V_2=\frac{P_1*}{P_2}*\frac{T_2}{T_1} *V_1$

$V_2=\frac{P_gas}{P_2}*\frac{T_2}{T_1} *V_1$

Here $P_2 \:and\: T_2$ are standard pressure and temperature respectively.

we have

$P_2=750mmhg \:and\: T_2=273K$

Substituting value, we get

$V_2=\frac{692.8}{750}*\frac{273}{308} *250$

$V_2= 819.51 ml$

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2 years ago

Atoms of elements that are in group 15 with what charge

liq [111]

Answer:

The elements in group 13 and group 15 form a cation with a -3 charge each.

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3 years ago

Fill in the blanks: when an atom absorbs energy, the electrons move from their _________________ state to an _________________ s

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<span>Fill in the blanks: when an atom absorbs energy, the electrons move from their (ground) state to an (excited) state. when an atom emits energy, the electrons move from a(n) (excited) state to their (ground) state and give off (energy)</span>

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3 years ago