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3 years ago

4. The blood vessels, heart and the blood make up

Chemistry

2 answers:

Ratling [72]3 years ago

8 0

Answer:

D, the cardiovascular system

Explanation:

The Cardiovascular System is the system at which blood circulates through our body

andrew-mc [135]3 years ago

3 0

D): the cardiovascular system because the blood vessels, heart and blood make up that system

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A piece of metal with a mass of 611 g is placed into a graduated cylinder that contains 25.1 ml of water, raising the water leve

jeka94

Mass of metal piece is 611 g and volume of graduated cylinder is 25.1 mL. When metal piece is placed in the graduated cylinder water level increases to 56.7 mL. The increase in volume is due to volume of metal piece that gets added to the volume of water.

Thus, volume of metal piece can be calculated by subtracting initial volume from the final one.

$V_{metal}=V_{final}-V_{initial}=(56.7-25.1)mL=31.6 mL$

Thus, volume of metal piece will be 31.6 mL. The mass of metal piece is given 611 g, density of metal can be calculated as follows:

$d=\frac{m}{V}=\frac{611 g}{31.6 mL}=19.33 g/mL$

Therefore, density of metal is 19.33 g/mL.

3 0

4 years ago

If 16.9 kg of Al2O3(s), 57.4 kg of NaOH(l), and 57.4 kg of HF(g) react completely, how many kilograms of cryolite will be produc

hodyreva [135]

Answer: 69.72 kg of cryolite will be produced.

Explanation:

The balanced chemical equation is:

$Al_2O_3(s)+6NaOH(l)+12HF(g)\rightarrow 2Na_3AlF_6+9H_2O$

To calculate the moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}$

moles of $Al_2O_3$ = $\frac{16.9\times 1000g}{102g/mol}=165.7moles$

moles of $NaOH$ = $\frac{57.4\times 1000g}{40g/mol}=1435moles$

moles of $HF$ = $\frac{57.4\times 1000g}{20g/mol}=2870moles$

As 1 mole of $Al_2O_3$ reacts with 6 moles of $NaOH$

166 moles of $Al_2O_3$ reacts with = $\frac{6}{1}\times 166=996$ moles of $NaOH$

As 1 mole of $Al_2O_3$ reacts with 12 moles of $HF$

166 moles of $Al_2O_3$ reacts with = $\frac{12}{1}\times 166=1992$ moles of $HF$

Thus $Al_2O_3$ is the limiting reagent.

As 1 mole of $Al_2O_3$ produces = 2 moles of cryolite

166 moles of $Al_2O_3$ reacts with = $\frac{2}{1}\times 166=332$ moles of cryolite

Mass of cryolite $(Na_3AlF_6)$ = $moles\times {\text {molar mass}}=332mol\times 210g/mol=69720g=69.72kg$

Thus 69.72 kg of cryolite will be produced.

8 0

3 years ago

24-Complete the following sentence:

docker41 [41]

Answer:

B. Solvent

Explanation:

In osmosis, water always moves from low solute concentration to high solute concentration. SOLUTE NEVER MOVES AS IT CANNOT PASS THE SELECTIVELY PERMEABLE MEMBRANE. alot of caps but need to stress this concept cuz otherwise this concept gets very confusing

8 0

3 years ago

Explain the Sun's role in the water cycle

timama [110]

It causes the water to evaporate from the earths surface so that it can cycle through again

3 0

3 years ago

The magnitude of an earthquake, measured on the Richter Scale, is M log1o T where / is the amplitude registered on a seismograph

just olya [345]

<u>Answer:</u> The magnitude rating for an earthquake causing an amplitude 10,000,000 times $I_o$ is 7.

<u>Explanation:</u>

Richter scale is defined as the scale which expresses the magnitude of earthquake on the basis of the seismograph oscillations.

The equation used to measure the magnitude of an earthquake on Richter scale is:

$M=log_{10}\frac{I}{I_o}$

where

I = amplitude registered on seismograph 100 km away from seismic center = $10,000,000I_o$

$I_o$ = small amplitude

Putting values in above equation, we get:

$M=\log_{10}(\frac{10000000I_o}{I_o})\\\\M=7$

Hence, the magnitude rating for an earthquake causing an amplitude 10,000,000 times $I_o$ is 7.

8 0

3 years ago