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3 years ago

HELP ASAP PLEASE!!!! 30 POINTS

Chemistry

2 answers:

valentina_108 [34]3 years ago

5 0

Answer:

it's option c

Explanation:

because if I'm not wrong I have learned these type of questions back 11 and I remember that rutherfords observation was few alpha particles were deflected by small angles.

BabaBlast [244]3 years ago

5 0

C. I use the other guys answer

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Zinc metal reacts with hydrochloric acid to produce zinc(II) chloride and hydrogen gas. How many liters of hydrogen gas will be

AleksAgata [21]

Answer:

0.120 L of hydrogen gas will be produced

Explanation:

Step 1: Data given

Mass of zinc = 10.0 grams

Volume of hydrochloric acid = 23.8 mL

Molarity of hydrochloric acid = 0.45 M

Molar mass of zinc =65.38 g/mol

Step 2: The balanced equation

Zn + 2HCl → ZnCl2 + H2

Step 3: Calculate moles Zinc

Moles Zn = mass Zn / molar mass Zn

Moles Zn = 10.0 grams / 65.38 g/mol

Moles Zn = 0.153 moles

Step 4: Calculate moles HCl

Moles HCl = molarity * volume

Moles HCl = 0.45 M * 0.0238 L

Moles HCl = 0.01071 moles

Step 5: Calculate limiting reactant

For 1 mol Zn, we need 2 moles HCl to produce 1 mol ZnCl2 and 1 mol H2

HCl is the limiting reactant. It will completely be consumed (0.01071 moles)

Zn is in excess. There will react 0.01071/2 = 0.005355 moles

There will remain 0.153 - 0.005355 = 0.147645 moles

Step 6: Calculate moles H2

For 1 mol Zn, we need 2 moles HCl to produce 1 mol ZnCl2 and 1 mol H2

For 0.01071 moles HCl we'll have 0.005355 moles H2

Step 7: Calculate volume H2

1 mol at STP = 22.4 L

0.005355 moles = 22.4 * 0.005355 = 0.120 L = 120 mL

0.120 L of hydrogen gas will be produced

4 0

4 years ago

When an electron moves from a lower energy level to a higher energy level, the atom:

Ede4ka [16]

Answer:

A. absorbs light

Explanation:

For an electron to move from a lower energy level to a higher energy level, energy needs to be added to the atom.

In most cases this required energy will be light: The electron of the atom will absorb the energy of the light and move to a higher energy level.

When said electron comes back to the lower energy level, the atom will conversely give off light.

5 0

3 years ago

Acetone is one of the most important solvents in organic chemistry. It is used to dissolve everything from fats and waxes to air

Yanka [14]

Answer: a. 79.6 s

b. 44.3 s

c. 191 s

Explanation:

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant

t = age of sample

a = let initial amount of the reactant

a - x = amount left after decay process

a) for completion of half life:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

$t_{\frac{1}{2}}=\frac{0.693}{k}$

$t_{\frac{1}{2}}=\frac{0.693}{8.7\times 10^{-3}s^{-1}}=79.6s$

b) for completion of 32% of reaction

$t=\frac{2.303}{k}\log\frac{100}{100-32}$

$t=\frac{2.303}{8.7\times 10^{-3}}\log\frac{100}{68}$

$t=44.3s$

c) for completion of 81 % of reaction

$t=\frac{2.303}{k}\log\frac{100}{100-81}$

$t=\frac{2.303}{8.7\times 10^{-3}}\log\frac{100}{19}$

$t=191s$

4 0

3 years ago

Compounds have the same properties as the elements they are made up of. Is it true or false

hodyreva [135]

( False ) this the answer

6 0

3 years ago

Butane (C4 H10(g), mc031-1.jpgHf = –125.6 kJ/mol) reacts with oxygen to produce carbon dioxide (CO2 , mc031-2.jpgHf = –393.5 kJ/

ankoles [38]

The balanced chemical equation for the combustion of butane is:

$2C_{4}H_{10}(g) +13 O_{2}(g)-->8CO_{2}(g)+10H_{2}O(g)$

Δ $H_{reaction}^{0}$ = Σ $n_{products}$ Δ $H_{f}^{0}_{(products)}$ -Σ $n_{reactants}$ Δ $H_{f}^{0}_{(reactants)}$

= $[{8*(-393.5kJ/mol)}+{10*(-241.82kJ/mol)}]-[{2*(-125.6kJ/mol)}+13*(0 kJ/mol)}]$ =[-3148kJ/mol+(-2418.2kJ/mol)]-[(-251.2kJ/mol)+0]

= -5315 kJ/mol

Calculating the enthalpy of combustion per mole of butane:

$1mol C_{4}H_{10}*( \frac{-5315kJ}{2mol C_{4}H_{10} })=-2657.5 \frac{kJ}{molC_{4}H_{10}}$

Therefore the heat of combustion per one mole butane is -2657.5 kJ/mol

Correct answer: -2657.5 kJ/mol

6 0

3 years ago