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4 years ago

Which age range would you expect to find a higher mortality rate in a typical disease?

1 answer:

8 0

A., because the infants are more susceptible to the disease and their resistance to any disease is still being refined and built

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If you hold a jar over a lit candle,a dark residue forms on the inside of the jar. This residue is

ollegr [7]

Answer:

carbon

Explanation:

6 0

3 years ago

A solution is made using 200.0 mL of methanol (density 0.792 g/mL) and 985.1 mL of water (density 1.000 g/mL). What is the mass

DaniilM [7]

Answer: The mass percent of methanol in solution is 13.85 %

Explanation:

To calculate the mass of water, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

For water:

Density of water = 1.000 g/mL

Volume of water = 985.1 mL

Putting values in above equation, we get:

$1.000g/mL=\frac{\text{Mass of water}}{985.1mL}\\\\\text{Mass of water}=(1.000g/mL\times 985.1mL)=985.1g$

For methanol:

Density of methanol = 0.792 g/mL

Volume of methanol = 200.0 mL

Putting values in above equation, we get:

$0.792g/mL=\frac{\text{Mass of methanol}}{200.0mL}\\\\\text{Mass of methanol}=(0.792g/mL\times 200.0mL)=158.4g$

To calculate the mass percent of methanol, we use the equation:

$\text{Mass percent of methanol}=\frac{\text{Mass of methanol}}{\text{Mass of solution}}\times 100$

Mass of solution = [158.4 + 985.1] g = 1143.5 g

Mass of methanol = 158.4 g

Putting values in above equation, we get:

$\text{Mass percent of methanol}=\frac{158.4g}{1143.5g}\times 100=13.85\%$

Hence, the mass percent of methanol in solution is 13.85 %

3 0

3 years ago

A student observes the chemical process described by this equation:

choli [55]

Answer:

Both are equal

Explanation:

Mass of starting material i.e Aluminium is $4.480 * 10^{-23}$ grams

The weight of oxygen is $2.65 * 10^{-23}$

There are 4 atoms of aluminium and 3 atoms of oxygen

Thus, the total mass of starting material is

$4 *$ mass of one atom of aluminium $+ 6 *$ mass of one atom of oxygen

$4 * 4.480 * 10^{-23} + 6* 2.65 * 10^{-23}$

$35.1 * 10^{-23}$ grams

Mass of new substance is also equal to

$4 *$ mass of one atom of aluminium $+ 6 *$ mass of one atom of oxygen

$4 * 4.480 * 10^{-23} + 6* 2.65 * 10^{-23}$

$35.1 * 10^{-23}$ grams

5 0

3 years ago

Do all comets have tails? Explain

Bad White [126]

Answer:

Some (most) has two tails.You can see the tails when the comets go near the sun.There are two types of comet tails,dust and gas ion. Comet tails can be over 600,000 miles (1 million km) long.Because the comet dust particles are so small, they are pushed away from the Sun into a long tail.They are made of ices, such as water, carbon dioxide, ammonia and methane, mixed with dust.There are so much more to discover about comets (which I might not know).

Hope that was helpful.Thank you!!!

5 0

3 years ago

According to the VSEPR theory, a molecule or ion of NH₃ will have a _____ shape.

Elan Coil [88]

Answer:

B) flat trigonal

Explanation:

All the Hydrogen atoms are arranged symmetrically around the Nitrogen atom which forms the base, and the two nonbonding electrons form the tip

4 0

3 years ago

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