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1 year ago

What is the best definition

Chemistry

2 answers:

Ann [662]1 year ago

7 0

Answer:

Explanation:

thermal expansion♡

Sav [38]1 year ago

5 0

answer:

I think is B. Thermal expansion is when an object's volume

decreases due to heat increase.

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PLEASE HELP ASAP FOR 25 POINTS!! :D

kondaur [170]

the x y axis is tipped so the earth is flat

3 0

2 years ago

Another gas was used for many years to float transportation balloons.

Alja [10]

Another gas that was used to fill balloons was hydrogen. The reason why hydrogen is not used today is because it use to cause many fires when it was used to fill balloons up.

Hope I helped you! :)

6 0

3 years ago

When 6.040 grams of a hydrocarbon, CxHy, were burned in a combustion analysis apparatus, 18.95 grams of CO2 and 7.759 grams of H

algol [13]

Answer: The empirical formula is $CH_2$ and molecular formula is $C_4H_8$

Explanation:

We are given:

Mass of $CO_2$ = 18.95 g

Mass of $H_2O$ = 7.759 g

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

In 44g of carbon dioxide, 12 g of carbon is contained.

So, in 18.59 g of carbon dioxide, = $\frac{12}{44}\times 18.59=5.07g$ of carbon will be contained.

For calculating the mass of hydrogen:

In 18g of water, 2 g of hydrogen is contained.

So, in 7.759 g of water, = $\frac{2}{18}\times 7.759=0.862g$ of hydrogen will be contained.

Mass of C = 5.07 g

Mass of H = 0.862 g

Step 1 : convert given masses into moles.

Moles of C = $\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{5.07g}{12g/mole}=0.422moles$

Moles of H= $\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{0.862g}{1g/mole}=0.862moles$

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C = $\frac{0.422}{0.422}=1$

For H = $\frac{0.862}{0.422}=2$

The ratio of C : H = 1: 2

Hence the empirical formula is $CH_2$ .

The empirical weight of $CH_2$ = 1(12)+2(1)= 14 g.

The molecular weight = 56.1 g/mole

Now we have to calculate the molecular formula.

$n=\frac{\text{Molecular weight }}{\text{Equivalent weight}}=\frac{56.1}{14}=4$

The molecular formula will be= $4\times CH_2=C_4H_8$

6 0

2 years ago

What is the name of an immune system response to a substance in food?

poizon [28]

Answer:

The adaptive (also called humoral or specific) immune system is typically only involved in immune responses to bacteria, bacterial toxins and virus antigens. It involves the production of antibodies (also called immunoglobulins) against a specific target. The target of an antibody is called an antigen.

3 0

3 years ago

An arrow is moving at 35m/sand travels for 5 seconds.how far did the arrow travel?

docker41 [41]

Answer:

175 meters

Explanation:

As it's velocity is 35m/s

so,

by formula

35 *5

175 meters

8 0

3 years ago