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Chemistry

1 answer:

shutvik [7]3 years ago

6 0

Answer:

i guess its the red wave so A

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A procedure calls for 0.250 kg of sugar. Your balance is in ounces. What mass in ounces should be weighed out on this balance?

Elena-2011 [213]

Answer:

8.81849

Explanation:

i believe the whole number would be this but usually i round to the second decimal point, i dont know if you could do that in chemistry tho

5 0

2 years ago

I need help and it for my science class

stealth61 [152]

They have energy.
If something is moving, it must have kinetic energy.
Let me know if you have any questions

5 0

2 years ago

For the reaction represented by the equation cl2 + 2kbr ® 2kcl + br2, calculate the percentage yield if 200. g of chlorine react

alexgriva [62]

The % yield if 200g of chlorine react with excess Potassium bromide to produce 410g of bromine is calculated as below

% yield = actual yield/theoretical yield x100
the actual yield = 410 grams

calculate the theoretical yield
by first calculate the moles of chlorine used

mole= mass/molar mass
molar mass of Cl2 = 35.5 x2= 71 g/mol

moles= 200g/71g/mol = 2.82 moles

cl2 +2 KBr = 2KCl +Br2

by use of mole ratio between Cl2 to Br2 which is 1:1 the moles of Br2 is also = 2.82 moles

theoretical mass = moles x molar mass
molar mass of Br2= 79.9 x2= 159.8 g/mol

moles= 2.82g x 159.8 g/mol = 450.64 grams

% yield is therefore = 410g/450.64 x100 = 90.98 %

5 0

2 years ago

A scientist fills a large, tightly sealed balloon with 75,000 mL of helium at STP.

pav-90 [236]

Considering the definition of STP conditions, 3.35 moles of helium are contained within the balloon.

<h3>Definition of STP condition</h3>

The STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C are used and are reference values for gases. And in these conditions 1 mole of any gas occupies an approximate volume of 22.4 liters.

<h3>Amount of moles of helium within the balloon</h3>

In this case, you know that scientist fills a large, tightly sealed balloon with 75,000 mL of helium at STP.

So, you can apply the following rule of three: if by definition of STP conditions 22.4 liters are occupied by 1 mole of helium, 75 L (75 L= 75000 mL, being 1 L= 1000 L) are occupied by how many moles of helium?

$amount of moles of helium=\frac{75 Lx1 mole}{22.4 L}$