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2 years ago

The heat of fusion of water is 80 cal/ g. How much energy is needed to melt 0.05 kg of ice?

1 answer:

7 0

80 cal/ g is same as 80 calories in each 1 gram. so,

80 cal= 1 gram

first, we need to convert the kg into grams. all you have to do is multiply by 1000 or move the decimal three times to the right.

0.05 kg= 50.0 grams

50.0 g (80 cal/ 1 gram)= 4000 calories

You might be interested in

(Yield Problem)

alex41 [277]

Answer:

Percent Yield Fe = 82.5%

Explanation:

The actual yield is the value produced after an experiment is conducted. The theoretical yield is the value calculated using the balanced chemical equation and atomic/molar masses.

To find the percent yield of iron (Fe), you need to (1) convert grams Al to moles Al (via atomic mass), then (2) convert moles Al to moles Fe (via mole-to-mole ratio from equation coefficients), then (3) convert moles Fe to grams Fe (via atomic mass), and then (4) calculate the percent yield. It is important to arrange the ratios in a way that allows for the cancellation of units. The final answer should have 3 sig figs to reflect the sig figs of the given values.

Atomic Mass (Mg): 24.305 g/mol

Atomic Mass (Fe): 55.845 g/mol

3 Mg + 2 FeCl₃ -----> 2 Fe + 3 MgCl₂

20.5 g Mg 1 mole 2 moles Fe 55.845 g
----------------- x ----------------- x ---------------------- x ----------------- =
24.305 g 3 moles Mg 1 mole

= 31.4 g Fe

Actual Yield
Percent Yield = ---------------------------------- x 100%
Theoretical Yield

25.9 g Fe
Percent Yield = -------------------- x 100%
31.4 g Fe

Percent Yield = 82.5%

5 0

1 year ago

Scientists need special tools to work in the laboratory. These tools are known as___________

inessss [21]

Instruments

The specific type of instruments depends on the type of laboratory that you're working in: some labs for example use electron microscopes, others use mass spectrophotometers, others use multiplex biochemical analyzers, etc. But very broadly, the specialized tools we use in the laboratory are usually referred to as "instruments"

3 0

3 years ago

PLS HELP QUICK ALOTTT OF POINTS

timofeeve [1]

Answer:

$\boxed {\boxed {\sf 0.80 \ mol\ F}}$

Explanation:

We are asked to find how many moles are in 4.8 × 10²³ fluorine atoms. We convert atoms to moles using Avogadro's Number or 6.022 × 10²³. This is the number of particles (atoms, molecules, formula units, etc.) in 1 mole of a substance. In this case, the particles are atoms of fluorine.

We will convert using dimensional analysis and set up a ratio using Avogadro's Number.

$\frac {6.022 \times 10^{23} \ atoms \ F}{ 1 \ mol \ F}$

We are converting 4.8 × 10²³ fluorine atoms to moles, so we multiply the ratio by this number.

$4.8 \times 10^{23} \ atoms \ F *\frac {6.022 \times 10^{23} \ atoms \ F}{ 1 \ mol \ F}$

Flip the ratio so the units of atoms of fluorine cancel each other out.

$4.8 \times 10^{23} \ atoms \ F *\frac { 1 \ mol \ F}{6.022 \times 10^{23} \ atoms \ F}$

$4.8 \times 10^{23} *\frac { 1 \ mol \ F}{6.022 \times 10^{23} }$

Condense into 1 fraction.

$\frac { 4.8 \times 10^{23} }{6.022 \times 10^{23} } \ mol \ F$

Divide.

$0.7970773829 \ mol \ F$

The original measurement of atoms has 2 significant figures, so our answer must have the same. For the number we found, that is the hundredths place. The 7 in the thousandths tells us to round the 9 in the hundredths place up to a 0. Then, we also have to round the 7 in the tenths place up to an 8.

$0.80 \ mol \ F$

4.8 × 10²³ fluorine atoms are equal to 0.80 moles of fluorine.

6 0

2 years ago

A piece of lithium is placed on the surface of some water in a beaker. hydrogen is given off. Lithium hydroxide is formed. What

Gala2k [10]

A piece of lithium is placed on the surface of some water in a beaker. Hydrogen is given off and Lithium hydroxide is formed. The word equation would be as follows:


lithium + water→ lithium hydroxide + hydrogen

Hope this answers the question. Have a nice day.

8 0

2 years ago

Chlorine can be prepared in the laboratory by the reaction of manganese dioxide with hydrochloric acid. HCl(aq), as described by

melisa1 [442]

Answer:

0.88 g

Explanation:

Using ideal gas equation to calculate the moles of chlorine gas produced as:-

$PV=nRT$