How many atoms in: 1. PbF3

Why do atoms of elements take part in chemical reaction?

Marina CMI [18]

Explanation:

During a chemical reaction, the atoms of the original substances gain, lose or share their electrons with those of the substances with which they are reacting. The reaction creates new substances made up of a new combination of atoms and a different configuration of electrons.

4 0

4 years ago

What happens when a solid is dissolved in a liquid

slava [35]

the solid particles take up the intermolecular spaces in the liquid.

8 0

4 years ago

The amount ofcalcium present in milk can be determined by adding oxalate to asample and measuring the massof calcium oxalate pre

Sauron [17]

Answer: The mass percent of calcium in milk is 0.107 %

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

Given mass of calcium oxalate = 0.429 g

Molar mass of calcium oxalate = 128.1 g/mol

Putting values in equation 1, we get:

$\text{Moles of calcium oxalate}=\frac{0.429g}{128.1g/mol}=0.0033mol$

The given chemical equation follows:

$Na_2C_2O_4(aq.)+Ca^{2+}(aq.)\rightarrow CaC_2O_4(s)+2Na^+(aq.)$

Sodium oxalate is present in excess. So, it is considered as an excess reagent. And, calcium ion is a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

1 mole of calcium oxalate is produced from 1 mole of calcium ion

So, 0.0033 moles of calcium oxalate is produced from = $\frac{1}{1}\times 0.0033=0.0033mol$ of calcium ions

Now, calculating the mass of calcium ions by using equation 1, we get:

Moles of calcium ions = 0.0033 moles

Molar mass of calcium ions = 40 g/mol

Putting values in equation 1, we get:

$0.0033mol=\frac{\text{Mass of calcium ions}}{40g/mol}\\\\\text{Mass of calcium ions}=(0.0033mol\times 40g/mol)=0.132g$

To calculate the mass percentage of calcium ions in milk, we use the equation:

$\text{Mass percent of calcium ions}=\frac{\text{Mass of calcium ions}}{\text{Mass of milk}}\times 100$

Mass of milk = 125 g

Mass of calcium ions = 0.132 g

Putting values in above equation, we get:

$\text{Mass percent of calcium ions}=\frac{0.132g}{125g}\times 100=0.107\%$

Hence, the mass percent of calcium in milk is 0.107 %

7 0

3 years ago

Sound waves are transverse mechanical waves. True False

allochka39001 [22]

False

Explanation:

Sound waves are longitudinal mechanical waves.

Mechanical waves are waves that requires a medium to propagate them.

A transverse wave is a wave that is propagated perpendicularly to its source.
An example is electromagnetic radiation.
A longitudinal wave is a wave that is directed parallel to their source.
Sound wave is a longitudinal wave.
It has series of rarefaction and compression along its travel path.
Rarefaction are areas of sparse particles.
Compression are areas with dense particles.

learn more:

Sound wave brainly.com/question/3619541

#learnwithBrainly

7 0

3 years ago

Deprenyl is an enzyme inhibitor that helps prevent the metabolism of dopamine in the brain. The chemical formula of Deprenyl is

mel-nik [20]

Answer:

0.007 g of deprenyl dose is required fro the patient with body mass of 70 kilograms.

Explanation:

The dose for treating Parkinson’s disease = 100 μg/kg body weight

Mass of patient's body = 70 kg

Amount of dose of deprenyl required = 100 μg/kg × 70 kg = 7,000 μg

1 μg = 0.00001 g

7,000 μg = 7,000 × 0.000001 g = 0.007 g

0.007 g of deprenyl dose is required fro the patient with body mass of 70 kilograms.

6 0

3 years ago

How many atoms in: 1. PbF3 - 2. Pb2O3 -