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2 years ago

Diseases can spread rapidly in cities. If a disease kills many people in a city but fewer in a rural area, this is an example of

Chemistry

1 answer:

Inga [223]2 years ago

5 0

Answer:

Density independent factor

Explanation:

in dense areas where people livein very close and tight spaces

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Pb(OH)Cl, one of the lead compounds used in ancient Egyptian cosmetics, was prepared from PbO according to the following recipe:

sladkih [1.3K]

Answer:

8.59 g

2.25 g

Explanation:

According to the given situation the calculation of grams of PbO and grams of NaCL is shown below:-

Moles of Pb(OH)CL is

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

$= \frac{10.0 g}{259.65g / mol}$

= 0.0385 mol

Mass of PbO needed is

$= 0.385mol Pb(OH) Cl\times \frac{1 mol PbO}{1molpb (OH) cl} \times \frac{223.2g PbO}{1mol PbO}$

After solving the above equation we will get

= 8.59 g

Mass of NaCL needed is

$= \frac{1mol\ NaCl}{1molPb\ (OH)Cl} \times \frac{58.45NaCl}{1mol NaCl}$

After solving the above equation we will get

= 2.25 g

Therefore we have applied the above formula.

7 0

2 years ago

For the homogeneous solution, consisting of kcl and h2o, indicate the type of forces that are involved.

zubka84 [21]

The pairs of substances I would expect to form homogeneous solutions when combined will form a homogeneous because both are polar and form dispersion forces, dipole-dipole and hydrogen bonding between the water molecules and ion-dipole forces between the K+ and Cl- ions and the water molecules.

4 0

3 years ago

What is the density of an object if its mass is 10 g and a volume of 2 mL?

Lilit [14]

Hi there! Let's solve this problem shall we!

⠀Volume = 10g

Mass = 2 mL

In this specific problem, they are asking us to find the density of the object. So, using the information given to us (volume and mass), let's solve the problem!

Now, if you remember, D = M ÷ V

So, let's fill in the blanks!

D = Our unknown value

M = 2mL

V = 10g

Here is the filled out formula:

D = M ÷ V

D = 2mL ÷ 10g

D = 5 g/mL

*Make sure you put the units for your final solution!*

4 0

1 year ago

One part of the cell theory states that all living things are made up of one or more cells. Scientists had to find ways to test

sergejj [24]

Answer:

A population or community research line can be carried out, wherever at a certain point in time, regardless of whether it is a cross-sectional study.

In addition, the people who would be the population to be studied or the object of study might or might not know the cause of the study (blind) while the researcher could be experimentally participatory.

Explanation:

They are prevalence studies, in which the presence of a health condition or state is determined in a well-defined population and in a determined time frame: one day, one week, a particular moment in life, even if it does not temporarily coincide in all the subjects (for example, the blood pressure figures at the time of entering the school or at the beginning of the holidays, the prevalence of diabetes in hospitalized patients on a given day, etc.).

They are like "photographs" of a state of affairs at a given moment. The simultaneous determination of what is understood by exposure and event does not allow defining causality.

5 0

2 years ago

Water is a pure substance. Which of the following is true about water? (4 points) Its compounds can only be physically separated

jonny [76]

Answer:

Water/H20 is a compound made of hydrogen and oxygen. Although water is the most abundant substance on earth, it is rarely found naturally in its pure form. Most of the time, pure water has to be created. Pure water is called distilled water or deionized water.

Explanation:

7 0

2 years ago