Pomocy zadanie na jutro chemia czesc 1 str 71 zadania 48 i 49

How many moles of water in 100 grams

Bond [772]

Answer:

There are approximately 5.55 moles

Explanation:

6 0

1 year ago

A metallurgist is making an alloy that consists of 325 grams of chromium (Cr) and 2.5 kg of iron (Fe). Find the total mass of th

Darya [45]

Answer:- Mass of the alloy is 2.8 kg.

Solution:- Mass of Cr in the alloy is 325 g and mass of Fe in the alloy is 2.5 kg. Mass of alloy would be the sum of masses of constituent metals.

Masses of the metals are not in the same units. So, we need to make the units equal. The want answer in kg so let's convert mass of Cr from g to kg.

Since, 1000 g = 1 kg

So, $325g\frac{1kg}{1000g}$

= 0.325 kg

Mass of alloy = mass of Cr + mass of Fe

mass of alloy = 0.325 kg + 2.5 kg = 2.825 kg

If we consider significant figures then as per the rules, the answer should not have more than one decimal place.

So, 2.825 kg is round off to 2.8 kg and hence the mass of the alloy is 2.8 kg.

5 0

2 years ago

Dissolving 5.28 g of an impure sample of calcium carbonate in hydrochloric acid produced 1.14 L of carbon dioxide at 20.0 °C and

swat32

Answer:

$\%\ mass\ of\ CaCO_3=93.37\ \%$

Explanation:

Given that:

Pressure = 791 mmHg

Temperature = 20.0°C

The conversion of T( °C) to T(K) is shown below:

T(K) = T( °C) + 273.15

So,

T = (20 + 273.15) K = 293.15 K

T = 293.15 K

Volume = 100 L

Using ideal gas equation as:

PV=nRT

where,

P is the pressure

V is the volume

n is the number of moles

T is the temperature

R is Gas constant having value = 62.3637 L.mmHg/K.mol

Applying the equation as:

791 mmHg × 1.14 L = n × 62.3637 L.mmHg/K.mol × 293.15 K

⇒n of $CO_2$ produced = 0.0493 moles

According to the reaction:-

$CaCO_3 + 2 HCl\rightarrow CaCl_2 + H_2O + CO_2$

1 mole of carbon dioxide is produced 1 mole of calcium carbonate reacts

0.0493 mole of carbon dioxide is produced 0.0493 mole of calcium carbonate reacts

Moles of calcium carbonate reacted = 0.0493 moles

Molar mass of $CaCO_3$ = 100.0869 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$0.0493\ mol= \frac{Mass}{100.0869\ g/mol}$

$Mass_{CaCO_3}=4.93\ g$

Impure sample mass = 5.28 g

Percent mass is percentage by the mass of the compound present in the sample.

$\%\ mass\ of\ CaCO_3=\frac{Mass_{CaCO_3}}{Total\ mass}\times 100$

$\%\ mass\ of\ CaCO_3=\frac{4.93}{5.28}\times 100$

$\%\ mass\ of\ CaCO_3=93.37\ \%$

3 0

2 years ago

Which of the following statements best describes why carbon can form a variety of organic compounds? Carbon atoms bond readily w

olga_2 [115]

Answer:
<span>Carbon readily forms covalent bonds with other carbon atoms.

Explanation:
As we know approximately more than 95 % compounds, either isolated, discovered or synthesized belongs to organic compounds containing carbon atoms.
This great diversity of organic compounds is due to following facts.

1) Catenation:
Carbon has a peculiar behavior of self linkage. This self linkage of one carbon with another is called as catenation. In this way carbon can form a long chain of carbon atom. A branching can also take place when one carbon is bonded further to three of four carbon atoms.

2) Isomerism:
Secondly the carbon containing compounds show isomerism. In which molecular formula is same but structural formula is different. For example molecular formula C</span>₅H₁₂ can make following compounds,

a) n-Pentane

b) 2-Methylbutane

c) 2,2-Dimethylpropane

3) Multiple Bonds:
Carbon can form multiple bonds i.e double bond like in alkenes and triple bonds like in alkyne.

Due to these factors carbon gets very high number of opportunities to form large number of compounds.

7 0

3 years ago

What are 5 physical changes in matter

Gennadij [26K]

Answer:

cutting, bending, dissolving, freezing, and boiling

Explanation:

A physical change is a change in one or more physical properties of matter without any change in chemical properties. In other words, matter doesn't change into a different substance in a physical change. Examples of physical change include but are not limited to, from solid to liquid or from liquid to gas are also physical changes.

3 0

2 years ago