How do the scientist know that cells exist

Answer Quick

kow [346]

Answer:

20.9%

Explanation:

The percentage by mass of solution is given by dividing the mass of solute in grams by the mass of solution in grams then multiplying it by 100%.

% Mass of solution = mass of solute/mass of solution × 100%

= (27.0 g/ 129.0 g) × 100%

= 20.93%

= 20.9%

7 0

3 years ago

Read 2 more answers

I need to know the answers

suter [353]

If you notice in the graph for antibiotic A, the number of bacteria actually INCREASES as time increases after the antibiotic was given. In the second graph, the amount of bacteria increases just a little bit (likely as the antibiotic sets in) and then decreases until no bacteria is left at all. This means that the antibiotic was the most successful because not only did the amount of bacteria decrease over time, but also all of the bacteria were eventually killed.

The last graph is shown as no antibiotic given. This is a graph showing the control group. There is always a control group in an experiment where nothing is done to the group. This is used to compare the results in the end of the experiment.

3 0

3 years ago

A certain liquid X has a normal freezing point of 7.60 °C and a freezing point depression constant K= 6.90 °C-kg-mol. Calculate

Dmitry [639]

<u>Answer:</u> The freezing point of solution is -5.11°C

<u>Explanation:</u>

Vant hoff factor for ionic solute is the number of ions that are present in a solution. The equation for the ionization of sodium chloride follows:

$NaCl(aq.)\rightarrow Na^{+}(aq.)+Cl^-(aq.)$

The total number of ions present in the solution are 2.

To calculate the molality of solution, we use the equation:

$Molality=\frac{m_{solute}\times 1000}{M_{solute}\times W_{solvent}\text{ in grams}}$

Where,

$m_{solute}$ = Given mass of solute (NaCl) = 7.57 g

$M_{solute}$ = Molar mass of solute (NaCl) = 58.44 g/mol

$W_{solvent}$ = Mass of solvent (liquid X) = 350.0 g

Putting values in above equation, we get:

$\text{Molality of }NaCl=\frac{7.57\times 1000}{58.44\times 350.0}\\\\\text{Molality of }NaCl=0.370m$

To calculate the depression in freezing point, we use the equation:

$\Delta T=iK_fm$

where,

i = Vant hoff factor = 2

$K_f$ = molal freezing point depression constant = 6.90°C/m

m = molality of solution = 0.370 m

Putting values in above equation, we get:

$\Delta T=2\times 6.90^oC/m.g\times 0.370m\\\\\Delta T=5.11^oC$

Depression in freezing point is defined as the difference in the freezing point of water and freezing point of solution.

$\Delta T=\text{freezing point of water}-\text{freezing point of solution}$

$\Delta T$ = 5.11 °C

Freezing point of water = 0°C

Freezing point of solution = ?

Putting values in above equation, we get:

$5.106^oC=0^oC-\text{Freezing point of solution}\\\\\text{Freezing point of solution}=-5.11^oC$

Hence, the freezing point of solution is -5.11°C

7 0

4 years ago

Why is the structure of atom important to scientist?

ss7ja [257]

Becauze were made of LOTS of atoms actually ECERYTHING EVEN AIR is made of atoms

3 0

3 years ago

What would be your reaction to a claim that a new element had been discovered, and it fit between tin (Sn) and antimony (Sb) in

Anton [14]

Answer:

As explained

Explanation:

My reaction will be positive and I will feel elated that a new elements has been discovered as this will be a modification of the earlier claim by berzelius and the likes that there are over 106 known elements ; Metal, Non Metals and Metalloids.

However, fitting the new discovered element in between Tin and antimony may be an issue, as the physical properties of the new elements has to be known, its melting point, metals or non metals as this is paramount to be able to classify the elements. if the elements fits in between tin and antimony, it is an indication that the elements is mot likely a metal or non-mental and may belong to group IVB or VB. Another issue is, the discoverer will have to create his own periodic table to be able to stand in with the discovery of Dimitriy Mendelev.

8 0

4 years ago